Moonglow The forgotten magic of our heavenly satelllite

Discussion in 'The Lounge' started by Fishers of Men, Nov 25, 2007.

  1. Fishers of Men

    Fishers of Men Senior Member

    THIS IS REAL LONG, IT TURNED INTO A CONTINUING EDUCATION ABOUT SEAMANSHIP AND WILL TRANSFORM AT THE END TO APPLYING FISHING TACTICS.
    A COMPILATION BY CAPTAIN AARON VAN BURNETT

    Hope these links work, probably have to enlarge a lil to read. I am going to try to get a post as often as possible that is going to continue from this topic ie: navigation, seamanship, gps, loran, radar navigation, lines of position, lat/long, minutes/degrees, elements of piloting, time, weather, fog situations, current sailing, buoyage system, mariners maps, earths magnetism, compass, deviations/corrections, moons gravity effects, dead reckoning, and I probably forgot to list something but it will come. probably those that don't follow from the beginning will be lost. Questions will be fine, but if you wait a lil bit they most likely will be answered. I figure that this coverage you can only get from expensive schooling and/or a life time of learning will help a bunch of people and refresh some of ours memories. Every new post will move forward and cover more depth. I am going to start with the moon. I wont get into tides much unless someone wants it.

    Moonglow The forgotten magic of our heavenly satelllite

    phases of the moon and much more. Key words: new moon, night sky, lunar cycle, lunar phases, crescent, synodic month, orbit, rotation, axis, waxing, waning, gibbous. The forgotten magic of our heavenly satellite.

    http://i202.photobucket.com/albums/aa305/FishersofMen/1moon.jpg
    http://i202.photobucket.com/albums/aa305/FishersofMen/2moon.jpg
    http://i202.photobucket.com/albums/aa305/FishersofMen/3moon.jpg
    http://i202.photobucket.com/albums/aa305/FishersofMen/4moon.jpg

    ZERO HOUR
    Over the years run many stories of men who have taken to the boats and found their way over a trackless ocean to land. In these years of many missions, few of those who go down to the sea in ships are without personal knowledge of sane brave man who likewise
    guided men to safety. From such men of the seven seas a few suggestions have been gathered that may be useful to others who face the zero hour. The result is far from complete, but it is from the sea, and of the sea, and not from the books, but from a almighty God, the celestial heavens and experience.
    The suns apparent motion is caused by the two motions of the earth. The resulting position of the sun over the earth is the greatest factor
    affecting the character and mode of existance of the human race. It determines the heat of the tropics, the cold and long artic nights, the calendar, the seasons, and day and night throughout the world. Also it is the most important element of nautical astronomy because its average position measures mean time and because it is most often observed by navigators.
    The moons apparent motion westward principally caused by the earths rotation is somewhat slower than that of the other navigational bodies, is characterized by it’s extremely rapid change of position among the stars. On an average the moon will rise about 51 mm. later each day, in NY’ s latitude, this retardation varies from 13 m to 8O mm. The fact for a navigator to remember is that the rate of increase of the moons GHA ( greenwitch hour angle) may be changing rapidly. The moon is easy to observe, and it’s observation often gives a much needed line of position obtainable from no other body.
    The solar day is the period of the earth’s rotation relative to the sun. The solar year is based on the period of the earths revolution about the sun, which requires approx. 365-1/4 days. The other units of time, month, week, hour, min, and second have origins deep in mans history. The ancient Egyptians used the rising of certain stars or star groups to divide their calendar into ten day periods. Such stars or star groups, rose successfully at intervals of roughly 40 mm, and so approximately 12 of them could be seen on any night. From this the night was divided into 12 hours and the entire day became 24 hours. The division of hours into 60 mm of 60 seconds each was a development of the ancient babylonian culture. The sun changes longitude at an almost uniform rate of 1511 an hour or 900’.
    "He appointed the moon for seasons" Psalms 104:19
    "The moon and stars to rule by night" Psalms 136:9
     
    Last edited by a moderator: Apr 30, 2015
  2. Fishers of Men

    Fishers of Men Senior Member

    Some of you might think that whats this all got to do with me and fishing?
    Well believe me it will all show a picture when we get thru this, just like pieces of a jig saw puzzle. I don't want some of you to think it's too confusing and give up, hang in there it will get easier. Might take me all winter, who knows but it's what we all have in common and like. I dont have time in the summer, so I figured with all the GPS questions and such on here that this would help with a lot of issues and making decisions ourselves about where to go, when to go and so on some of us have. All material shown you can follow along if you go to the library and get the "Primer of Navigation" and Duttons Navigation and Piloting " by Elbert S Maloney. I am only going to hit on certain things to an extent because it should be enough understanding to move on your own from there. This information being brought forward is my understanding and 50 yrs of experience on the water are going to be straight from these books and of my opinion only. Debatable issues from these facts can be taken to another thread. And with all the talent I see on this site, I welcome any comments or oversites feel free to chime in.

    Today we are going to clarify "time" issues. I know there are confused people over how distance/time/degrees work. You will see how minutes for example shown on gps and lorans, charts, works with distance. I will constantly throughout all of this, remind you to ask yourself "where am I?" That will be very clear before long as to why.

    TIME
    THE subject of time, always difficult for students of navigation, has been greatly simplified since 1933. Today, with the same kind of time used in civil life, the position of the sun, the moon, or any of the navigational stars or planets may be taken from the Almanacs without the use of apparent or side real time. This simplification does not eliminate the necessity for determining the exact instant of an observation; chronometers and timekeeping are discussed in the next chapter.
    2101. The natural measure of time is the sun’s apparent motion over the earth which causes the periods of darkness and light, as well as the seasons. It does not provide a practical measure, however, because the apparent motion of the true sun is not uniform ( and units of time measured thereby are of varying duration. The variation is slight but clocks cannot be regulated by apparent time)
    To retain the advantage of a time based on the sun, an imaginary sun, called the mean sun, is used. The mean sun. is an imaginary body which would appear to move westward around the earth at a uniform rate equal to the average rate of the true sun. If both suns were seen in the sky, following the same track, their positions would coincide at only four instants during the year but would never appear far apart.
    2102. Mean time, sometimes called civil mean time or civil time, is time as measured by the motion of the mean sun. Under various names, it is the time we live by and is the only kind of time essential to present- day navigation.
    A civil day is the interval of time required for the mean sun to make one revolution about the earth. It is divided into 24 hours of 60 minutes of 60 seconds always of the same duration. The day begins at midnight (Oh) at the instant the mean sun crosses the lower meridian of the observer. As the sun moves westward around the earth, the time increases, The instant of the upper transit of the mean sun across the meridian marks noon (12h) mean time for that meridian. The sun then continues westward until it again crosses the lower meridian, and a civil day of 24 hours, always of the same duration, is ended never to return.

    For most purposes of civil life the day is divided into two periods of 12 hours each. Time before noon is marked A which means at or before the sun has crossed the meridian. After noon, time to midnight is marked P.M. indicating time post or after the sun crosses the meridian. In the Almanacs the hours are numbered from 0 to 24 without special designations.
    Although the duration of a civil day is the same for all places, the time of day is common only to points on the meridian of longitude from which the momentary east-west position of the mean sun is measured. The sun’s transit westward over that meridian marks the instant of noon, 12h, mean time, but the sun already will have crossed meridians to the eastward where time is therefore after noon or later; for points westward the time is before noon or earlier.
    Listeners to international broadcasts know that standard time at London (75° to the eastward) is five hours later than New York standard time, just as the football fan knows that time on our Pacific Coast (450 to the westward) is three hours earlier than at New York. Minor differences in exact civil time are less well understood. If one walks across Manhattan Island on 42nd Street, New York City, the exact local time will have changed about 9 seconds. To the eastward of New York at Boston, local time is about 12.5 minutes faster; westward, at Philadelphia, the local time is about 5 minutes slower than at New York.
    Local Mean Time (L.M.T.). An infinite number of different mean times is possible, each being L.M.T. for the meridian on which the time is based. Comparatively few are in standard use and these are given special designations, the most important to navigators being Greenwich mean time (G.M.T.).
    The term L.M.T. as used in navigation generally means local mean time for the meridian of longitude of the ship, although it may mean local time at any place.
    Greenwich mean time is the local mean time for all points on the meridian of Greenwich, England. The reason for its importance is that some place had to be chosen as a base for the tabulations in the almanacs. Since Greenwich historically is on the prime meridian for the measurement of longitude, the Greenwich meridian became also the meridian of reference for the predicted time of occurrence of astronomical events.
    Greenwich mean time, sometimes called Coordinated Universal Time (UTC), is the standard for civil time keeping and for navigation. It is not strictly uniform, but when corrected by a few milliseconds for variations in the earth’s motion, it gives UT1 for use by geophysicists and others requiring a more uniform measure of time.
    Greenwich mean time is the same throughout the world. Hence, activities of world-wide scope keep their clocks and watches set to Greenwich mean time.
    244 Primer of Navigation
    Military communications and other operations are regulated by this time.
    The lower, circular drawing of Fig. 2103 is the sphere of the earth as viewed from above its south pole. Around it is shown the apparent progress of the mean sun around the earth and how its position measures
    G.M.T. The upper, rectangular diagram illustrates the same facts by plotting succeeding geographic positions of the mean sun on a map of the world. For convenience the sun is shown as moving westward along the equator (00 Dec l.), a permissible assumption because the westward motion of the mean sun, which is the measure of civil time, is not affected by the sun’s varying declination.
    As always in the measurement of mean time, the day begins at mid night (Oh), the instant the center of the mean sun, marked (0) in the drawing, crosses the lower meridian, 180 degrees E or W, at the time of its lower transit. As the mean sun moves westward at the rate of 15° per hour the time grows later and at (3), having moved westward 45° to the meridian 135° E of Greenwich, G.M.T. is 3h OOm A.M. or simply 0300 when stated in accordance with Navy practice. When the mean sun crosses the meridian of Greenwich at the time of upper transit, or simply transit, G.M.T. is 12M or 1200. For reasons stated later, this instant is almost never the exact time of transit of the true sun. After noon the mean sun continues to travel westward, always at a constant rate of 150 of longitude per hour. When it is 45° west of Greenwich it is 3 P.M. or 1500 G.M.T. and thus onward until its succeeding lower transit marks the end of the day (24b) and a new day begins.
    In a similar manner, local mean time for any meridian is measured by the relative position of the mean sun to that meridian.
    Time and longitude.
    Either quantity may be expressed in units of arc or in units of time. Understanding this relation between time and longitude is facilitated by the following considerations:
    Longitude is measured in degrees (°) and minutes (‘) of angular measure. Arcs representing time, however, are often expressed in units of time as a measure of arc. As 24 hours of time are required for the mean sun to traverse a circle of 360° at a uniform rate of 150 per hour, the circle may be divided into 24 hours with each arc further divided into minutes and seconds of time. When an arc is so divided time units may be used as a measure of arc. Useful equivalents of identical arcs measured in degrees and minutes of arc or by units of time may be expressed in these ways:
    3600 = 24 hours
    15° 1 hour
    1° 4 minutes
    15’ = 1 minute
    1’ = 4 seconds
    (I am telling you that it is a different time on opposite sides of the street in NY city at any given time!)
    Here is a diagram:
    http://i202.photobucket.com/albums/aa305/FishersofMen/timediagram.png
     

  3. Fishers of Men

    Fishers of Men Senior Member

    I will go to the compass now, later on we will incorporate every thing we have discussed into a quiz when I get the time to compile it. We have all winter and these are my favorite topics. The quiz will incorporate all kinds of real life instances on the water ie: conditions, safety, fire, getting home in adverse conditions and so on. Stuff that experience gives, that you can’t get in any class. I am still learning and appreciate any input. I cant change the title, maybe a mod can. I think it should say “seamanship”. Probably gain more interest. Please point out any errors or typos, I get burned out eyeballs lookin at this thing. I hope the links are readable, might have to use the magnifing glass or enlarge.

    THE MAGNETIC COMPASS
    The magnetic compass is one of the oldest of the navigator’s instruments. Its origin is unknown, but apparently the Vikings were familiar with it in the eleventh century. Although records are scanty and inexact, it is probable that the magnetic compass was independently developed by the Chinese at about the same time. The earliest compasses probably consisted of an elongated piece of lodestone, iron ore having magnetic properties, placed on a wood chip and floated in a bowl of water. Rather quickly, this developed into an iron needle thrust through a straw and floated on the surface of a container of water; the lodestone had to be applied to the needle each time the “compass” was to be used.
    Initially, a compass was used only to indicate north, but soon the concept of marking other directions around the rim of the bowl was introduced. The directions were given the names of the various winds, now known as North, East, South, and West; these are the cardinal directions. Next are the intercardinal directions: NE, SE, SW, and NW. (comment, the cardinal directions are not used here, they are over seas in countrys not using our system. You will see it mentioned again when we do the bouy system.) Still finer subdivisions are the combination directions: NNE, ENE, ESE, etc.; and the by-points: NxE, NNExN, NNExE, etc. This system results in a complete circle divided into 2 points (1 point = 11-1/4°) and there are half-points and quarter points. The point system was widely used until relatively modern times, but is now obsolete except for some minor use on sailing craft.
    Because of the difficulty at sea in using a needle floating freely in an open bowl of water, the next development was that of using a pivot at the center of a dry bowl. Not for some centuries was the liquid put back in, this time in an enclosed chamber, as now is the case in modern magnetic compasses.
    The magnetic compass still retains its importance, despite the invention of the gyrocompass. While the latter is an extremely accurate instrument, it is highly complex, dependent on an electrical power supply, and subject to mechanical damage. The magnetic compass, on the other hand, is entirely self-contained, simple, comparatively rugged, and not easily damaged.
    Standard and Most vessels of any size carry at least two magnetic compasses; these steering are the standard compass and the steering compass. The standard compass, whenever possible, is located on the ship’s centerline…
    For clarification purposes:
    http://i202.photobucket.com/albums/aa305/FishersofMen/compass2.png
    I can’t seem to make anything with pics or diagrams post here, so I have to do the link thing.
    http://i202.photobucket.com/albums/aa305/FishersofMen/compass3.png
    http://i202.photobucket.com/albums/aa305/FishersofMen/comp4.png
    (pay real attention to this magnetic field link)
    continued from the link:
    76.1° N, longitude 100.0° W and the south magnetic pole is near 65.8° S, 139.4° E; these locations are somewhat indefinite and change irregularly over a period of years. Some studies have shown that the poles appear to move in daily, cycles over an elliptical path having a major axis of about 50 miles; such movement is, of course, too slight to affect practical navigation in nonpolar latitudes.
    Magnetic meridian
    At the surface of the earth, the lines of force become magnetic meridians. These are irregular lines which cannot be printed on charts covering large areas; their irregularity is primarily caused by the non uniform distribution of magnetic material in the earth.
    The magnetic lines of force can be divided into components. For the navigator, the horizontal and vertical components are important, and are discussed as variation and dip in subsequent articles.
    Variation
    Magnetic meridians indicate the direction of the earth’s magnetic field; but only in a very few places do the magnetic and true meridians coincide. The difference at any location between the directions of the magnetic and true meridians is the variation, sometimes called magnetic declination. It is called easterly (E) if the compass needle, aligned with the magnetic meridian, points eastward or to the right of true north, and westerly (W), if it points to the left. Variation results from the horizontal component of the earth’s magnetic field.
    Variation is important to the navigator because the magnetic com pass, responding to the earth’s magnetic field, is in error in measuring true geographic direction by the amount of the variation (Var. or V). The magnetic variation and its annual change are shown on charts, so that directions indicated by the magnetic compass can be corrected to true directions. Since variation is caused by the earth’s magnetic field, its value changes with the geographic location of the ship, but is the same for all headings of the ship.
    Secular change
    The earth’s magnetic field is not constant in either intensity or direction. The changes are diurnal (daily),yearly, and secular (occurring over a longer period of time). The changes in intensity are too small to have any effect in navigation. The same is true of diurnal changes in direction, except in polar regions, where diurnal changes of 7° have been observed.
    The secular change in direction, however, is a real factor in navigation. Although it has been under observation for more than 300 years, the length of its period has not been fully established. The change generally consists of a reasonably steady increase or decrease in the variation, which is the inclination of the magnetic meridian to the true meridian at a given place. This change may continue for many years, sometimes reaching large values, remain nearly stationary for a few years, and then reverse its trend.
    http://i202.photobucket.com/albums/aa305/FishersofMen/comp6.png
    http://i202.photobucket.com/albums/aa305/FishersofMen/comp7.png
    http://i202.photobucket.com/albums/aa305/FishersofMen/comp7-1.png
    http://i202.photobucket.com/albums/aa305/FishersofMen/comp8.png
    continued from the link:
    dination (dip) and for intensity of field, horizontal, vertical, and total; they are revised when required by changes in the earth’s magnetic field. Of greatest interest to a navigator is DMAHC Chart 42, Magnetic Variation Chart of the World for the Year 1975, a simplified which is shown in Figure 406.
    While these charts are useful for planning purposes, the large-scale chart of the area involved should always be consulted in setting a course by magnetic compass or converting a magnetic compass bearing to a true bearing for plotting, since there are many small irregularities in variation that cannot be shown on the small-scale world charts. In addition, there are very small areas of local magnetic disturbance that may or may not be indicated on the chart. At one place off the coast of Australia, near Cossack, the variation changes from 56° E to 26° W in a distance of about 180 yards, less than the length of a ship; areas of local disturbance of lesser magnitude extend over nearly three miles of navigable water. There are many others of less extreme nature, but still of a magnitude and extent that must be taken into account by a navigator.
    Modern compass
    The basic mechanism of modern magnetic compasses is exactly construction the same as that of the very earliest ones used, a small bar magnet freely suspended in the magnetic field of the earth. Refinements have been added for greater accuracy, steadiness of indication, and ease of reading, but the basic mechanism remains unchanged.
    Compass components
    The modern marine magnetic compass is contained in a glass-topped bowl made of nonmagnetic material. The letters in the following description refer to the corresponding components in this illustration. At the forward side of the bowl is the lubber’s line, which indicates the direction of the ship’s head). At the center of the bottom of the bowl is a vertical pin, the pivot, upon which the compass card (B) rests. To the bottom of this card are attached two or more magnets (A) aligned with the north-south axis of the compass card. The card is marked around its outer edge with graduations at suitable intervals, 1°, 2°, or 5°, from 000° at the point where the card indicates compass north clockwise through 360°; cardinal and intercardinal directions may also be shown on the card in some designs.
    In order to reduce friction on the pivot and to dampen vibration, the compass bowl is filled with a clear fluid (D) which is not subject to freezing at normal temperatures. The card has afloat or air chamber (E), designed so that it will support all but a minute percentage of the weight of the card with the attached magnets. Lastly, the bowl is fitted with an expansion bellows (F) which permits the bowl to remain filled as the liquid expands and contracts with temperature changes.
    Operation of the magnetic compass:
    Deviation

    When a compass is mounted on a vessel, its magnets align them selves with the magnetic field in which they exist. Assuming for the moment that there are no local influences (objects of magnetic material or electrical currents), this alignment will be parallel to the horizontal component of the earth’s magnetic field. The compass card will maintain this alignment regardless of the vessel’s heading.
    As the compass card is attached to the magnets, the 0000 mark on the card always points in the direction of compass north, and the ship’s compass heading is indicated by the lubber’s line. If there are no local disturbing influences, no deviation (see Article below), then this is also the magnetic heading. When a compass is installed, great care must be taken to align the lubber’s line exactly parallel to the center line of the ship. The compass bowl and lubber’s line are constrained to turn with the ship, thus the direction of the lubber’s line from the center of the compass always represents the direction of the ship’s head. Since the 0000 mark on the card is always toward the magnetic north, the direction indicated on the compass card opposite the lubber’s line is the ship’s heading. As the ship turns, the lubber’s line turns with it, while the compass card remains aligned with compass north, so that the heading at any moment is indicated at the lubber’s line. Remember that it is the lubber’s line, and not the compass card, that turns.
    As stated above, a compass needle free to turn horizontally tends to align itself with the earth’s magnetic lines of force. Unfortunately, it is not free to do so in a steel ship; such ships have marked magnetic properties of their own, and these tend to deflect the compass from the magnetic meridian. The divergence thus caused between the north-south axis of the compass card and the magnetic meridian is called deviation (Dev. or D). Even in a vessel made of wood or fiber glass there is enough magnetic material on board, engines, fuel and water tanks, rigging, etc. to cause deviation.
    The possibility of deviation from electrical circuits must not be overlooked. Direct currents flowing in straight wires establish magnetic fields. Care must be taken that all wiring in the vicinity of a compass is properly installed to eliminate or reduce any effect on the compass; checks must be made for deviation with the circuits turned on and off.
    Although deviation differs from variation in that the latter is caused by the earths magnetism, the two are designated in the same manner.
    Thus, if no deviation is present, the compass card lies with its axis in the magnetic meridian and its north point indicates the direction of magnetic north. If deviation is present and the north point of the compass points eastward of magnetic north, the deviation is named easterly and marked E. If it points westward of magnetic north, the deviation is named westerly and marked W.
    The navigator can easily find the correct variation by referring to the chart of his locality. Deviation, however, is not so simple to ascertain. It varies not only on different ships, but on any particular ship it varies with changes in the ship’s heading. Also, it often changes with large changes in the ship’s latitude.
    Compass error
    The algebraic sum of variation and deviation is compass error. The navigator must understand thoroughly how to apply variation, deviation, and compass error, as he is frequently required to use them in converting one kind of direction to another.
    From the foregoing it should be apparent that there are three ways in which a direction can be expressed:
    As true, when referred to the true (geographic) meridian as the reference of measurement.
    As magnetic, when referred to the magnetic meridian as the reference of measurement.
    As compass, when referred to the axis of the compass card as the reference of measurement.
    Any given direction may be expressed in all three of these ways, if it is understood that:
    True differs from magnetic by variation.
    Magnetic differs from compass by deviation.
    Compass differs from true by compass error.

    Figure 412a
    http://i202.photobucket.com/albums/aa305/FishersofMen/412a.png
    This seems complicated from the Duttons book. I will simplify it afterwords.
    Outlines a ship in which is shown the card of the standard compass. OC is the direction of the compass needle. OM is the magnetic meridian, and OT the true meridian. The two outer circles, concentric with the standard compass card, represent magnetic and true compass roses, thus indicating magnetic and true directions. The observer is at 0. The magnetic meridian is 12° eastward (right) of the true meridian; therefore, the variation of the locality is 12° E. It is added to the magnetic direction of M (0° on magnetic rose) to obtain the true direction of M (12° on true rose). The compass needle is 8° eastward (right) of the magnetic meridian; therefore, the deviation is 8° E on the ship’s heading shown. It is added to the compass direction of C (0 degrees on compass card) to obtain the magnetic direction of C
    (8° on magnetic rose). The compass error is the algebraic sum of the
    variation and deviation or CE= 20° E. It is added to the compass
    direction of C (0° on compass card) to obtain the true direction of C
    (20° on true rose). The bearing of object A from the ship is shown as
    20° psc, (per ships compass) 30° magnetic, and 40° true. In practice, bearings are expressed
    in three-numeral groups e.g., 0200, 0300 and 040°. The ship’s heading is 300° psc (note lubber’s line LL), 3080 magnetic, and 3200 true.
    As already noted, easterly deviation is added (+) to compass in converting to magnetic, easterly variation is added (+) to magnetic in converting to true, and easterly compass error is added (+) to compass in converting to true. Conversely, they are subtracted (—) when converting in the reverse order.
    Figures 412b and c will show westerly variation and deviation and demonstrate that the above rules of application should be reversed for westerly errors.
    http://i202.photobucket.com/albums/aa305/FishersofMen/412b.png
    Westerly variation, but easterly deviation.
    Correcting and uncorrecting
    Compass direction to a magnetic or true direction or of converting a magnetic direction to a true direction is one of “correcting,” or removing errors. If easterly errors are added, it is obvious that westerly errors are subtracted, and no separate rule is needed.
    The opposite of correcting is called uncorrecting. The process of Un- correcting is one of converting a true direction to a magnetic or com pass direction or a magnetic direction to a compass direction by applying errors. If easterly errors are added and westerly errors subtracted when correcting, then the reverse is true when uncorrecting. Hence, the one rule, correcting add east, is sufficient to cover all four possible situations:
    Correcting, add east, subtract west.
    Uncorrecting, add west, subtract east.
    Rules for applying compass errors:
    Figure 412c. Westerly variation, but easterly deviation.
    http://i202.photobucket.com/albums/aa305/FishersofMen/412c.png
    T REEL just asked a good question: "Why is the ship center not in the middle of the compass rose center ?" Very good question. It should be in the center since it is supposed to be under a perfect condition, not that the compass should be as close to center as possible deal. I never noticed that. These drawings are right out of the book, I didn't make them. Thank you for noticing the detail. I will make a note on the page.


    It is convenient to have a thumb rule to serve as an aid to the memory applying the above principles. The following will serve: When correcting, easterly errors are added, or simply, correcting add east. When applying this rule, it is necessary to consider a compass direction as the “least correct” expression of direction as it contains two errors, variation and deviation. Magnetic direction is thus “more correct” than compass as it contains only one error, variation. This is so even when the axis of the compass card is closer to the true meridian than is the magnetic meridian. Magnetic direction is, however, “less correct” than true direction, which contains no errors.
    Correcting and uncorrecting
    Hence the process of converting a compass direction to a magnetic or true direction or of converting a magnetic direction to a true direction is one of “correcting,” or removing errors. If easterly errors are added, it is obvious that westerly errors are subtracted, and no separate rule is needed.
    The opposite of correcting is called uncorrecting. The process of Un- correcting is one of converting a true direction to a magnetic or com pass direction or a magnetic direction to a compass direction by applying errors. If easterly errors are added and westerly errors subtracted when correcting, then the reverse is true when uncorrecting. Hence, the one rule, correcting add east, is sufficient to cover all four possible situations:
    Correcting, add east, subtract west.
    Uncorrecting, add west, subtract east.
    C-A-E Now to simplify
    Note that to get the other three forms from the basic statement “correcting add east (which can be memorized as “C-A-E”), you must change two, but only two, of the three words. If “correcting” is changed to “uncorrecting,” then either add must be changed to subtract, or east to west. If correcting is not changed to uncorrecting but “east” is changed to “west,” then “add” must be changed to “subtract.” The basic phrase, C-A-E, and the rules to change only two words will suffice to meet all problems of correcting and uncorrecting.
    C-D-M-V-T An alternative method for remembering the rules of correcting and uncorrecting involves using the first letters of the following words:
    Compass, Deviation, Magnetic, Variation, and True and letting these be the initial letters of words that form an easy-to-remember sentence. A convenient one to use is Can Dead Men Vote Twice? Using this sentence to remember the order, write down just the initial letters and arrange them vertically: (To do it in reverse order you can go TVMDC remembered by: true virgins make dull companions. by which you add W going down and add E going up with the formula. From the + in the middle draw a arrow up and one down.)
    w C ___
    D __
    + M ___
    V __
    E T __

    To the left of the column, draw a double-ended arrow, placing a W at the top, and E at the bottom and a plus sign in the center as illustrated. The addition of “At Elections” to the sentence above will assist in remembering that in the direction C-D-M-V-T the procedure is to Add East. The arrow heads have nothing to do with actual direction but apply only to the direction of proceeding through the initial letters of the memory phrase, whether correcting from compass to true or uncorrecting from true to compass.
    Now, by placing the given information in the corresponding
    blanks, the unknown values can easily be computed following the rule of the form.
    Examples of Example 1: A ship is heading 127° per standard compass. For this heading the deviation is 16° E and the variation is 4° W in the area.
    Required: (1) The magnetic heading. (2) The true heading.
    Solution: The problem is one of correcting. Since the deviation is easterly, it must be added. Hence, the magnetic heading is 127° + 16° = 143°. To find the true direction we are again correcting, and since the variation is westerly, it is subtracted. Hence, the true heading is 143° — 4° = 139°. In this case the compass error is 16° E — 4° W = 12° E. Applying this directly to the compass heading, we find the true heading is 127° + 12° = 139°, as previously determined.
    Answers: (1) MH 143°, (2) TH 139°.
    Example 2: A ship’s course is 347° psc. The deviation is 4° W and the
    variation is 12° E.
    Required: (1) The magnetic course. (2) The true course.
    Solution: Again the problem is one of correcting. The deviation is subtracted and the magnetic course is 347° — 4° = 343°. The variation is added and the true course is 343° + 12° = 355°.
    Answers: (1) MC 343°, (2) TC 355°.
    Example 3: A ship’s course is 009° psc. The deviation is 2° W and the variation is 19° W.
    Required: (1) The magnetic course. (2) The true course.
    Solution: The problem is one of correcting and since both errors are
    west they are subtracted. The magnetic course is 009° — 2° = 007°.
    The true course is 007° — 19° = 348°. Since 000° is also 360°, this is the
    same as 367° — 19° = 348°.
    Answers: (1) MC 007°, (2) TC 348°.
    Example 4: From a chart the true course between two places is found to be 22 1°. The variation is 9° E and the deviation is 2°W.
    Required: (1) The magnetic course. (2) The compass course.
    Solution: It is necessary to uncorrect; the easterly variation is sub tracted and the westerly deviation is added. The magnetic course is 221° — 9° 212°. The compass course is 212° + 2° = 2 14°.
    Answers: (1) MC 2 12°, (2) CC 2 14°.
    Naming variation, Another problem that can arise is that of assigning a “name” east or deviation, or west—to variation, deviation, or compass error when the numerical compass error value has been found by subtraction between two directions. Here, the simple phrase rhymes as follows:
    Compass least, error east.
    Compass best, error west.
    “Least” means lesser numerically, and “best” means greater numerically. For variation from true directions, “magnetic” can be substituted for “compass” in the rhyme.
    Example 5: A navigator sets up a compass at a spot on shore near the ship’s anchorage. This compass, not being affected by the iron and steel of the ship, is free from deviation and indicates magnetic direction. From the chart the navigator determines the true bearing of a distant mountain peak to be 320°. By compass it bears 337°. The ship bears 076° by compass from the observation spot ashore.
    Required: (1) The variation. (2) The true bearing of the ship.
    Solution: The numerical difference between the true and magnetic bearings is 17°; since the magnetic bearing is greater—”best” by the rhyme—the variation is westerly, 17° W. To find the true bearing of the ship is “correcting,” and we use the previous rule—correcting, subtract west; thus, the true bearing of the ship is 076° — 17° = 0590.
    Answers: (1) V 17° W, (2) TB 0590.
    Example 6: Two beacons are so placed ashore that when seen in line from seaward they mark the direction of a channel, 161° T. Seen in line from a ship heading up the channel, they bear 157.5° by compass. The chart shows the variation for the locality to be 2.5° E.
    Required: (1) The compass error. (2) The deviation.
    Solution: The numerical difference is 161° — 157.50 = 3.5°. Since “compass is least” the “error is east.” The compass error is the alge braic um of the variation and deviation. Hence, the deviation is the algebraic difference or 3•50 — 2.5° = 1.0° E.
    The table below summarizes the six examples; answers that were
    determined in each problem are underscored. A line for compass error (CE) has been added.
    http://i202.photobucket.com/albums/aa305/FishersofMen/13apic.png
    Deviation table
    Deviation changes with a change in the ship’s heading. The deviation is determined by comparing a direction shown on the compass with the known magnetic direction. Several methods of accomplishing this will be explained later. The deviation on various headings is tabulated on a form called a deviation table, or magnetic compass table, and posted near the compass. A copy of the table should also be kept posted in the chart house.
    It provides blanks for filling in certain information regarding the compass and the correctors used to reduce the deviation. Two different columns of deviation are shown, one marked “DC OFF” and the other “DG ON.” “DG” refers to the ship’s degaussing coils. Since the deviation may be somewhat different when the degaussing coils are energized, it is necessary to determine the deviation under both conditions. A deviation table for a vessel without degaussing coils would be simpler by half.
    The deviations shown in this illustration are somewhat larger than would be acceptable under normal conditions of a properly adjusted compass. Such larger values are given here to provide practice in calculation and interpolation, the procedure for determining an intermediate value between two tabular listings.

    Comment: Every vessel has a different deviation, no two are the same. So a table must be made up for every vessel. Also, any thing you put close to the compass will change the deviation, weather it be a watch, powercord, cigarette wrapper, cell phone etc…”wonder why were off course? Shoulda seen the bouy by now, got enough gas?”
    COMPASSES
    A) Theory
    Earth is huge magnetic field.
    Magnetized pointer lines up with force fields.
    North pole is off-center in northern Canada and changing.
    All compasses point to that area (boat rotates around it.)
    B) Installing
    Make sure new compass in correct N-S and S-W.
    Line up N-S/E-W with 2 books.
    Put compass on one book, line up N-S reverse one with compass if not 180 degrees
    adjust to 1/2 with no magnetic tool (if 4 degrees error, adjust by 2 degrees) do again until correct repeat for EW
    Install on center line of vessel
    string a line from bow to center of stern
    measure equal distance from line to install
    C) Make deviation card
    Run several courses and record compass reading (better to line up 2 fixed points in front of you) work compass corrections for deviation card
    Test for electrical interference by observing for changes when you turn on wipers, radio. If changes remove and twist wires.
    Compasses are not really accurate due to off-center poles and electrical interference on your vessel but the “repeatability” us extremely accurate.
    Always check your compass on leaving the dock and starting your day.
    What does it read at the dock or on the first leg of your daily routine?
    Does it agree with your GPS?
    Remember it’s the most important piece of navigation equipment:
    Stations don’t go off air, doesn’t break down and doesn’t need electricity to run.
    And finally, ONLY HEADINGS HAVE DEVIATION. and charts are in TRUE you MUST convert when plotting a course.
     
    Last edited by a moderator: Apr 30, 2015
  4. Fishers of Men

    Fishers of Men Senior Member

    Here are links to the Coast Guard Navigational Rules. The definitions are going to be needed to follow along and naturally the rules of the road along with some other needed info.

    http://www.navcen.uscg.gov/mwv/navrules/rotr_online.htm

    http://boatsafe.com/nauticalknowhow/boating/colregs.html

    A partial list of
    NAUTICAL TERMS:
    ABAFT Any direction between the beam and astern.
    ABEAM Relative bearing of 270 deg or 090 deg.
    ADRIFT Loose; not secured to a stationary object.
    AGROUND When any part of the ship is resting on the bottom.
    ALOFT Above the decks; on the mast or rigging.
    ANEMOMETER Instrument for measuring WIND velocity
    ANEROID BAROMETER DRY method to measure AIR PRESSURE.
    BEAM Measurement of GREATEST WIDTH of a vessel.
    BELAY Act of securing line to cleat; also means to disregard.
    BOLLARD Large round upright to TIE UP (ON DOCK.)
    CLEAT Device to tie up to like a pair of horns.
    COCKLE Kink in a rope or line.
    DEAD RECKONING Method of navigating from known position with out taking SET and DRIFT into account.
    DEVIATION Compass error caused by the VESSEL (correct with Deviation card.)
    DRAFT The vertical distance from waterline to the keel.
    DRIFT The SPEED that the current is taking you.
    DROGUE Sea anchor; any device to hold you into the wind.
    EBB The time the tide is flowing OUTWARD.
    FLOOD The time that the water is flowing INWARD.
    FREEBOARD The distance from the deck to the waterline.
    HEAVE TO The act of stopping or slowing the vessel.
    HEAD REACH The distance from when the prop stops and vessel stops.
    LATITUDE The distance NORTH (and SOUTH) of the equator measured in degrees and minutes (a degree is 60 miles; a minute a mile.)
    LINE Rope that has been assigned a specific job.
    LONGITUDE Measurement EAST and WEST of PRIME MERIDIAN. (GMT)
    MEAN HIGH WATER Average high tide; used to measure things above.
    MEAN LOW WATER Average low water; used to measure DEPTH.
    MEAN SEA LEVEL Average of low and high water.
    NEAP TIDE That tide that has the least RANGE.
    PAY OUT Expresses the idea “to feed out.”
    PELORUS A hand held compass to take bearings. (A HAND HELD HAS NO DEVIATION)
    RANGE Distance; two aids to navigation used to line up a narrow approach; the difference between the HIGH and LOW tide.
    RIGHT HAND Rope that is twisted to the right; a prop that twists to the RIGHT to move vessel FORWARD
    RUNNING LIGHTS Sidelights and stern lights COMBINED.
    SEA ANCHOR Any device used to keep vessel into the sea.
    SET The direction that natural forces take you.
    SIDE LIGHTS Colored lights on the front (RED to PORT.)
    SPRING LINE A mooring line that goes at an angle.
    SPRING TIDE A tide that is higher or lower than normal.
    STEERAGE WAY That speed that a vessel may be steered.
    TIDE The RISE and FALL of the water VERTICALLY.
    VARIATION Compass error caused by the off-center poles.
    VEER Allow a line to run out freely.
    YAW A vessel moving sideways violently.
    A partial list of
    MISCELLANEOUS:
    1) Lee side = that side sheltered from the wind.
    2) Fathom =6 feet.
    3) Heave to = stop the vessel
    4) Approach a dock or mooring against the wind and tide.
    5) Shallow water = a) sluggish rudder.
    b) trim is changed. (fore and aft balancing.) c) vessel will squat more.
    6) To stop cavitation (prop turning too fast), decrease speed.
    7) A V-shaped ripple pointing upstream can be caused by a snag.
    8) Pivot point of a vessel:
    a) 1/3 distance aft of the bow when going ahead.
    b) 1/3 the distance ahead of the stem when backing.
    9) Muddy water shows deeper on a depth sounder - two readings are caused by a muddy bottom.
    10) Patent log measures the distance traveled through the water.
    11) Protect a compass by covering it.
    12) Gunwale - the top edge of a hull.
    13) Caulk - a temporary patch on a hull leak.
    14) Man overboard - approach from leeward. Besides proper maneuvering throw a floating object, turn toward the side he fell off and post a lookout. Make a Williamson Turn (60 degrees from course, hard over then 180° from original course.)
    15) The water is deepest at the outside of the curve of a river bend.
    16) Bow cushion - effects of navigation in a narrow, steep-sided channel. Bow will be pushed away and stern sucked in.
    17) Stern suction - same. (These will cause the bow to be pushed away from the channel side.)
    18) Steering, signaling and communications shall be checked before getting underway.
    19) Pyrotechnic devices (flares) are good for 3 years.
    20) EPIRB (Emergency Position Indicating Beacon) is operating properly when light comes on and ocillating tone heard.
    21) Life rafts are equipped with orange smoke signals.

    VESSEL HANDLING
    Single screw - turns clockwise in forward if right-hand; wheel backs to port. Left-hand wheel backs to starboard
    Twin screw - to clear the inboard wheel using the outboard engine, use after bow spring line with outboard engine ahead.
    In forward gear, the bow will always swing toward the drag (engine that is stopped.)
    Note: a) if a question about twin screw vessels use a paper or book to simulate the action of the vessel. b) also a twin screw has less or little paddle wheel effect.
    A partial list of
    CPR AND ARTIFICIAL RESPIRATION
    1) NORMAL BREATHING RATE IS 12 PER MiNUTE FOR ADULTS
    20 PER MINUTE FOR CHILDREN
    2) CPR MUST BE CONTINUED. AS LONG AS POSSIBLE.
    3) MUST BE STARTED ASAP AS BRAIN DIES IN 4-6 MINUTES.
    4)10 APPLY CPR, PINCH NOSE CLOSED AND BREATH INTO MOUTH.
    5) IF SUBJECT VOMITS:
    TURN HEAD ASIDE
    SWEEP OUT VOMIT
    CONTINUE
    6) PULSE RATE (HEART) IS 60 - 100 BEATS PER MINUTE BEST DETECTED IN CAROTID ARTERY IN NECK
    HELICOPTER TRANSFER
    A: REQUESTING HELICOPTER
    GIVE: ACCURATE POSITION, WEATHER CONDITIONS, TIME, SPEED AND COURSE, WIND DIRECTIONS, TYPE OF VESSEL, MEDICAL CONDITIONS, ANY CHANGE IN PATIENTS CONDITION, ESTABLISH WHAT CHANNEL
    B: WHILE UNDERWAY
    MAINTAIN CONTINUOUS RADIO CONTACT, (SET UP SCHEDULE TO CONTACT), SELECT AND CLEAR SUITABLE AREA, LIGHT PICKUP AREA, AIM SEARCHLIGHT UPWARD (EASY LOCATION), NOTIFY PILOT OF PICK-UP AREA
    C: UPON ARRIVAL
    MOVE PATIENT TO PICK UP AREA, SLOW TO BARE STEERAGEWAY, AIM INTO WIND, PUT LIFE JACKET ON PATIENT
    D: PICKUP
    SIGNAL PILOT TO START, ALLOW BASKET TO TOUCH DECK, (STATIC ELECTRICITY), DO NOT TIE ANYTHING FROM HELICOPTER TO BOAT, IF YOU MUST MOVE THE LITTER, UNHOOK IT, LOAD PATIENT, THEN MOVE IT BACK, ATTACH HOOK TO LITTER, KEEP LITTER FROM SWAYING WITH LINE.

    OVERVIEW
    1. INFORMATION ON CHARTS, IN BOOKS
    • READ INFORMATION IN LEGENDS OR BOOKS.
    2. SPEED MADE GOOD (SMG)
    • USUALLY 2 TIMES GIVEN AND 2 POINTS.
    • APPLY 6O DST USING MEASUREMENTS BETWEEN PLACES AND TIME.
    3. COURSE MADE GOOD (CMG)
    • GIVEN: • 2 PLACES.
    MARK BOTH, WALK RULERS TO COMPASS ROSE.
    4. COMPASS COURSE:
    • SAME AS ABOVE JUST USE COMPASS CORRECTIONS FOR ANSWER.
    5. YOUR POSITION BY 3 BEARINGS PSC TO 3 PLACES
    A. CONVERT ALL PSC TO TRUE (CAN ONLY DRAW TRUE.)
    DEFAULT IS SIGHTING OVER COMPASS,
    USE VESSELS HEADING FOR DEVIATION
    “HAND HELD” COMPASS THERE’S NO DEVIATION.
    B. DRAW THE BEARINGS.
    C. WHERE THEY CROSS IS YOUR POSTION (USUALLY THAT SECTION), FIX IS IN MIDDLE OF TRIANGLE.
    6. LEEWAY (ESTIMATE OF WIND ON YOUR VESSEL)
    A. DRAW THE APPROXIMATE COURSE ON PAPER.
    B. DRAW THE DIRECTION OF THE WIND (FROM WHENCE IT COMES.)
    C. ADD OR SUBTRACT DEGREES FOR ANSWER.
    7. TIDE/CURRENT PROBLEM
    • A. LOOK UP THE CORRECTION IN THE BACK OF THE BOOK.
    • B. WRITE DOWN THE CORRECTiON TIME OR RATIO.)
    • C. NOTE THE REFERENCE STATION AT TOP, WRITE IT DOWN.
    • D. LOOK FOR THE TIDE/CURRENT TIME/RATIO.
    • E. SUBTRACT/ADD TIME OR MULTIPLY BY RATIO FOR CORRECT TIME OR HEIGHT.
    8. SET/DRIFT
    A. DRAW THE STARTING POINT, DIRECTION AND USED 60 X D divided by S/T FOR DISTANCE, LABEL IT AS DR (SEMICIRCLE, DOT, TIME.)
    B. DRAW THE ACTUAL FIX WHERE YOU WERE.
    C. DRAW A LINE FROM THE DR TO THE FIX (SET LINE) LABEL WITH a.
    D. WALK IT TO COMPASS ROSE AS SET LINE.
    E. MEASURE THE DISTANCE FROM DR TO FIX.
    F. APPLY 60 X D/ST FOR DRIFT.
    9. ESTIMATED POSITION
    A. DRAW THE STARTING POINT, DIRECTION AND USED 60 DST FOR DISTANCE, LABEL IT AS DR (SEMICIRCLE. DOT, TIME.)
    B. DRAW THE SET (GIVEN) THRU THE DR (LABEL IT WITH A)
    C. USE 60 DST TO ASCERTAIN DISTANCE ALONG LINE FOR EP.
    10. COURSE TO STEER (COMPENSATING FOR CURRENT)
    A. DRAW THE STARTING POINT, DIRECTION AND USE 60 DST FOR DISTANCE, LABEL IT.
    B. DRAW THE SET/DRIFT FROM THE INDICATED POINT
    C. MEASURE THE LINE “BACKWARDS” (TURN INTO CURRENT.)
    D. MAKE THAT POINT YOUR POINT TO AIM.
    E. DRAW LINE AND WALK TO COMPASS ROSE FOR PTA.
    11. TIME TO ARRIVE
    A. FIGURE THE DISTANCE.
    B.USE 60 DST TO FIGURE TIME.
    C. ADD TIME TO TRAVEL FROM START FOR ANSWER
    D. SAME AS ABOVE EXCEPT TO SUBTRACT FROM TARGET TIME.
    13. WHAT IS DISTANCE FROM? TO?
    FIND 2 NAMED PLACES, DRAW LINE, WALK TO LATITUDE SCALE OR, LOOK IN THE BACK OF REED’S COMPANION FOR ANSWER.
    TIME/SPEED AND DISTANCE
    60D D=SXT S=60D T=60D
    SXT 60 T S

    I) DISTANCE 55 MILES X 45 MINUTES SPEED?________ TO FIND DISTANCE MULTIPLY SPEED TIMES TIME DIVIDE BY 60
    D=55X45 =41.25 DISTANCE + 60
    2) SPEED DISTANCE 72 MILES IN 112 MINUTES SPEED? SPEED 60X72/112=38.6 KNOTS
    14. TIME 45 MILES AT 12 KNOTS
    60X45112=225 MINUTES (3 HOUR 45 MINUTES)

    RED FLAG WORDS
    The purpose of this sheet is to alert you when certain problem words show up.
    Most of the errors are misreading not the material.
    SAILBOAT Means the vessel is sailing under sail alone (can’t be anchored)
    NUC Exceptional Circumstance broken down, accident / R/R The (red over red lights) captain is dead
    RAM Working, paid for doing, designed for / Same fog signal anchored or underway
    UNDERWAY Two types making way (wake) / or not making way (wake)
    SAFE SPEED ALWAYS BEST ANSWER
    ACTION AMPLE and in time
    NARROW CHANNEL +20/-20 & sail/fishing/crossing Western River power only downbound/upbound/crossing
    TSS -2O/sail/fishing/crossing (grouped together)
    OVERTAKING ALL WAYS give-way don’t mix with OVERTAKEN
    SAILBOAT R.O.W. STAND-ON downwind or starboard tack / No maneuvering signals
    POWER CROSSING To right has R.O.W. and give-way don’t cross ahead
    OPEN WATER R.O.W. New reels catch fish so purchase some / Note: assume open water unless stated
    FOG No R.O.W. I bear ahead - bare steerageway/ Radar change course alone
    GIVE-WAY EARLY and SUBSTANTIAL
    STAND-ON Hold course and speed but may take action in doubt must take action in extremis
    TOW LIGHT The yellow over white stem light/Not 2 cr3 masthead
    MASTHEAD LIGHT 2 FOR PUSH, HIP & -200 ASTERN: 3 for +200 Power only no MH NUC/fish/sail/towed/pilot/ -50 trawl
    SAIL LIGHTS Tricolor -20 R/G on any never together
    FISHING R/W (red over white light) is fishing at night note: same fog signal anchored or underway
    TRAWLING NOT TROLLING G/W (green over white) trawling at night! note: aft MH (masthead) if +50
    DREDGE NO ANCHOR LIGHTS/Already has seven
    CBD Constrained by draft (crushed beer can day symbol) never on Inland
    SIGNALS INT’L: I AM? (except narrow channel) / INT’L: I INTEND? (exchange signals) ONLY SHORTS ON LIGHT 1/2/3/5 (IN SIGHT ONLY)
    FOG SIGS Only used when can’t SEE/No R.O.W. in fog
    AGROUND 3 strokes before and after anchor signal (rapid ring of bell at least every minute)
    OVERTAKING NC INT only/ prolong, prolong +1 or 2 shorts - I intend?
    SPECIAL FLASHING INLAND only on front of barge (yellow 180-225°)
    TOW ASTERN SAME FOR ALL/ Si, 2/3 MH, yellow stern
    INLAND TOW HIP/PUSH y/y /No white on Western Rivers
    RUNNING LIGHTS None no wake NUC/RAM/fish/trawl (NURFT) all others on when underway
    NO MASTHEAD NUC, fish, trawler-50, sail, pilot note: RAM, CBD, minesweeper shows masthead lights
    SAME FOG SIGNAL Whether anchored or underway - RAM and fishing only
    SUBMARINE LIGHT Yellow 6 flashes (I sec) then off for 6 seconds
    SIDE LIGHTS OUT When not making wake: NUC, RAM, FISHING, TRAWLING NURFT - ALFS DUMB BROTHER
    NAVIGATION AIDS White in middle/green on port/red on starboard/ group 2+ 1/yellow for special
    PLOT TERMS C course to steer PTA point to aim
    CMG course made good SOA speed of advance
    SMG speed made good CPA closest point
    PSC per steering (or ship’s or standard) compass only use when word compass” is used
    T True heading (always use if in doubt)
    Your “memory aid” and this list will put you very close to your target of 90% on
    RULES OF THE ROAD. (Look up the definitions in the rules link)

    PLOTTING HINTS
    Plotting Hints...Navigation by Chart and Problem Data
    Locations/Fixes...may be one of or combination of
    • LAT/LONG, LORAN-C or Range(s) and/or Bearing(s) to known object(s).
    • If by three bearings...may get “cocked hat”; assume position in center.
    • Bearings “to Stbd or Port beam 900 relative or 2700, respectively.
    Unless the problem dictates you do otherwise
    • Headings, bearings Use TRUE degrees
    • Distances Are in NAUTICAL miles
    • Speeds Are KNOTS (nautical miles per hour)
    • Time HOURS (take care in additions/subtractions)
    Relationships between Speed. Distance and Elapsed Time
    Memory Relationship Distance=Speed X Time D= S X T
    Speed= Distance/Time S = D/T
    Time= Distance/Speed T = D/S
    Develop Plotting Disciplines
    • Use an fine line, sharp pencil for plotting on chart;
    • Indicate Fix by circle, DR and EP by half circle with “24 hour times”;
    • Indicate directions of bearings, headings, sets by line with arrow head for direction;
    • Use appropriate abbreviations (see below);
    • Exercise care in ‘walking’ headings or bearings from the compass rose and measuring distances with dividers. Slight miscue’s can mean trouble!
    Measuring Distances
    • Always on the VERTICAL scale of the chart, i.e., between parallels of latitude.
    Typical Abbreviations for use on the chart plot
    • FIX “known” location • PTA Point to Aim • DR Dead Reckoned Pos.
    • C Course or Heading • CTS Course To Steer • EP Estimated Pos.
    • S Speed thru water ‘ETA Est. Time of Arrival • PSC Per Ships (or std.) Compass
    • CMG Course Made Good • SMG Speed Made Good
    Compass Corrections
    • Deviations can change with vessel’s heading... take note if the problem alters deviation with different headings (normally with ‘multiple leg’ problems only);
    • if necessary, make corrections with: TVMDC ÷ W (fall down) after completing problem.
    Speeds / Direction
    • RPM or Prop Speeds are speeds of vessel thru water not SMG;
    • Set/Drift... Direction/Speed vessel is carried due to water currents. (* make sure you understand the nature of the vessel speed given.)
    Ship’s Movement... Resultant of several effects
    • Vessel’s propulsion system (oars, sails, engines, etc.,); PLUS
    • Water currents. i.e., a set (direction) at a drift (current speed) ; PLUS
    • Wind effects known as leeway; (normally NOT taken into account) but if problem requires, it will typically be given as “westerly (or easterly) leeway degrees”; simply add (or subtract) to compass corrections as with westerly (or easterly) deviations.
     
  5. Fishers of Men

    Fishers of Men Senior Member

    I was asked by REEL and his OGF mail was returned to me undeliverable. So here goes: “Why does the center of all this have an offset ?”

    We have not got to the center yet. :) Hope this answers a hard to answer question. There are too many topics that all coincide to list right now. I am spending a lot of time pulling out my research and thoughts on these matters.
    This is mainly a large focus on safety and education for new boaters on the Great Lakes. And a call out to experienced seaman/fishermen to refresh their memories, chime in, and to share information. How conditions are effected by the sun, moon, earths movements, predicting weather patterns on your own, applying conditions to fishing, survival, boat handling, why things work certain ways and so on. I can only pump a bunch of factual info out there and what anyone does with it is up to them. It will get intense and those with little knowledge will probably have a hard time keeping up. I would appreciate it if everyone would write their questions down and periodically I will ask for questions and or/input. I appreciate any oversights I may have or forgotten to mention. I am getting ready to put up a section on charts, applying info that was already posted to show how all these things come together. All the way through I will incorporate pre read posts to new material so the applications are applied and the results seen for themselves. I might not have started in the right order, but I guess you could call it a informal free online maritime course for educational purposes. I am going to cover a lot of material. I figure anyone could print out things that could be used as helpful future referral. A lot of members posted that they had no time for classes and such and would really like to learn. I am thankful for all those that I have boated/fished with and learned from all my life and I have plenty of time to share what I can, and learn more on these never ending processes, with anyone on these topics that I enjoy.
    Thanks for the question.
     
  6. Fishers of Men

    Fishers of Men Senior Member

    Well, so far we can get an idea here from where the almanac/gps and others get there sun/moon best fishing days/times from. Not covered is tidal info that has to do with all this. Unless someone asks, I'll throw it in. I crammed a lot of info in to start, now I will go a little slower and if questions arise on what is already posted, bring ‘em on.

    There were posts by Donkey, Ezbite and a few others that stated common sense and knowing your surroundings when you leave the dock and while your on the water to stay aware of all landmarks, bouys, towers, buildings and such at all times. These things are very important navigational aids. Everything we are going to cover is a navigational aid. When on the water you must use ALL the navigational aids available to you, sometimes you wont “see” many. We will try to help you notice more aids that can be overlooked. These things will get you home safely whether it be that adverse conditions set in, restricted visibility, strange areas, etc…day or night. And yes, when we get done here, applying what we have learned could even get a person lost at sea more chance for survival and even back somewhere. A lot of this info will be forgotten and or never used, but might spring back some memory come the day it is needed, even if it’s only a small segment that would help matters in emergency. Knowledge and experience on the water makes the difference of what different people do out there. For instance, some say that us night guys in the cold and dangerous circumstances are crazy. Not so, with the proper knowledge, experience and wisdom it is a normal everyday thing for us. When situations occur, all this comes into play and you deal with it at the time. Speaking of time, timely means RIGHT NOW, immediately, no hesitation or having to think about it. Many times you don’t get a second chance. If you have a good educated crew on board, things go automatically and nice and smooth. Not to panic, just deal with it, time is of the essence. Knowledge, experience and respect for the elements. Moving on…

    There is a lot of info on the magnetic forces in a previous post, that need to be recognized for whatever lat/long you are in at the time. If you look on a chart, there are areas that have different compass rows. They are spaced apart in particular areas do to magnetic variations in the earth. In the center of the compass rows is and area that says for example: variation 10 degrees 30’ W and a date. Then under that, it will show an annual increase, of say 6’. (This ‘ is all I can show for minutes.) This is do to the magnetic changes in that area effecting your compass. Charts should be of the latest update always, as you will not be where you think you are. The bottom left corner on a chart shows the publication date. Now, if all you have to work with because other means went down (gps etc…) is an old chart, you can take the above example of 6’ and times that difference from the year noted by the variation shown, to the current year to be close. But it is no real cigar. It might help you to miss an obstruction and or get you close to home though. For instance variation 10 degrees 30’W 1990 and this is 2007, you would subtract 1990 from 2007 = 17 yrs. Now take the 6’ for 17 yrs, 6 X 17= 102 minutes. As you can see, you would have been WAY off course going by the old chart. Always use the compass rows closest to you for reasons explained above. ALL measurements of distance MUST come from the latitude side of a chart, for lines of latitude are smaller circles parallel to the equator around the earth. On most charts parallels of latitude (Lat or L) appear as horizontal straight lines. (I will get into distances in the next post.)
    The Earth is oblong, so lines of longitude are “squeezed” together at the north and south poles. As shown before, (and I know you printed the links) a mile is 1 minute of latitude, that’s where the saying comes from “a mile a minute”. I think now we should change course for clarification purposes:

    MARINERS’ MAPS
    (charts are NOT maps)
    Maps drawn on the surface of a globe correctly represent the curved surface of the earth; maps or charts on a flat surface, especially those of large areas, are necessarily distorted. The smallest globe, although impracticable for the daily work of the navigator, is an invaluable aid to understanding charts and various other matters with which navigators are concerned. Fig. 1100.
    http://i202.photobucket.com/albums/aa305/FishersofMen/1100.png
    Definitions on a globe. The drawing of the sphere of the earth illustrates certain definitions important to all mariners.
    The earth is assumed to be a sphere with its axis passing through its north pole and its south pole.
    Great circles. If a plane passes through the center of the earth, as when cutting an orange in half, its intersection with the earth surface is a great circle. The plane must pass through the center or only smaller circles result. Arcs of great circles, often appearing as straight lines, are important elements of chart construction.
    Angles, as measured from the center of the earth, are the principal basis for measurements on its surface. An angle is formed by the intersection of two lines and is measured by the divergence of the lines without regard to their length, as in Fig. 1101.
    http://i202.photobucket.com/albums/aa305/FishersofMen/1101.png
    The units of angular measurement result from dividing any circle, whose center is at the intersection of two lines, into 360 degrees ; each degree is further divided into 60’, and each minute into 60”. In practical navigation, it is sufficiently accurate to express seconds (“) of arc by the nearest tenth of a minute (‘).
    The equator is a great circle around the earth midway between the poles. Its distance from each pole is everywhere 90°, or one-fourth of a circle, but the equator, because it is a complete circle, is divided into 360°.
    Meridians are best described as halves of great circles extending from pole to pole always at right angles to the equator. A line drawn through the ship, north and south to the poles, is the meridian of the ship. A similar line through Greenwich is called the prime meridian and is the zero line from which longitude is measured. Meridians on Mercator charts appear as vertical, parallel straight lines.
    Parallels of latitude are smaller circles around the earth, parallel to the equator. On most charts, parallels of latitude appear as horizontal straight lines.
    Latitude (Lat. or L.) defines position on the earth north or south from the equator. The latitude of a place on the surface of the earth is the arc of the meridian between the equator and that place. Latitude is 0 degrees on the equator and never exceeds 90°, which is the latitude of either pole; it is marked N (+) or S (—). Observe how the latitude of Scotland Light ship, off New York, is measured in Fig. 1100.
    http://i202.photobucket.com/albums/aa305/FishersofMen/1100.png
    Longitude (Long.) defines position on the earth east or west from the meridian of Greenwich, which is called the prime meridian. Longitude of a place on the earth’s surface is the arc of the equator between the prime meridian and that of the place. It is measured East (E) or West (W) from the meridian of Greenwich (0° Long.), and therefore does not exceed 180° or halfway around the earth, where east meets west.
    (comment: coincide this with the diagrams on “time” from earlier.)
    Position of any point at sea or on the land may be defined by its latitude and longitude. For example, the position of Scotland Lightship is in Lat. 40° 27’ N and Long. 73° 55’ W.
    The true direction of a line on the surface of the earth at any point along the line is the angle the line makes with the meridian through that point. It is generally measured from 0° at true north around clockwise to 360 degrees.
    A nautical mile (6076 ft.) is the unit of distance used at sea. By international agreement, it is equal to exactly 1852 meters and is approximately equivalent to 1’ of latitude or to 1’ of arc of any great circle of the earth. A nautical mile is approximately one-seventh longer than the statute mile (5280 ft.).
    Mercator’s projection: To represent approximately the spherical surface of the earth on a flat surface, maps are constructed in many different ways according to the purpose for which a particular type of map is devised. Mercator’s projection, previously outlined is the system by which most maps used by mariners are constructed. Charts of this type have been in use since the publication about 1569 by Gerar dus Mercator, a Flemish geographer, of his then excellent map of the world. The navigator may not be called on to construct a Mercator chart but a knowledge of how such charts are developed is an aid to understanding many things related to voyages at sea. The drawings in Fig. 1102 represent three stages in the development of a Mercator chart.
    http://i202.photobucket.com/albums/aa305/FishersofMen/1102.png
    Imagine the true map of the earth’s surface on a globe to be unfolded as if an orange were peeled. The segments shown in (A) everywhere represent 30° of longitude but are bounded by converging meridians as on the earth. The distance between these meridians at 60° N or 60° S is only 900 miles, whereas at the equator they were 1800 miles apart. The true length of 1’ of longitude continually decreases from 1 mile on the equator to 1/2 mile in 60° N or S and thence to 0 at the poles regardless of how it may appear on any chart. Minutes of longitude are never a measure of nautical miles except on the equator.
    The horizontal lines drawn across the segments above and below the equator represent the parallels of 30°, 60°, and 80° N or S latitude. These are parallel lines; they do not converge as do the meridians of longitude, and the actual distance between any two such parallels of latitude is everywhere the same. The length of 1’ of latitude, which is measured on a great circle of the earth, is 1 mile according to one definition of a nautical mile. Minutes of latitude are always a measure of nautical miles in their latitude. For example, the distance between a parallel of 30° and that of 60° is 30° or
    30 X 60’ = 1800’ = 1800 nautical miles.
    In (B) the segments from the globe appear as expanded with their edges joined in vertical, parallel straight lines which represent the meridians on the Mercator chart shown as a cylinder wrapped around the earth. These apparently parallel meridians appear equally distant from one another, whereas on the earth the true distance between them constantly decreases as they converge from the equator to the poles. Except on the equator all of the east and west dimensions on the chart have been expanded, this expansion being greater, the greater the latitude.
    To avoid local distortion, the expansion of the longitude scale at any given distance from the equator is applied to the latitude scale in that area. The scale at the sides of the chart which represents a minute or a degree of latitude continually increases from the equator to north or south and becomes impossibly great when approaching the poles. This is why drawings (B) and (C) reach only to 800 N; charts of the polar regions cannot be constructed on Mercator’s projection.
    The drawing (C) shows half of the cylinder unrolled as a flat chart of the Western Hemisphere, from 60° S to 80° N. Within these limits it represents a Mercator projection of the map shown on the globe (B).
    In practice charts of such large areas are seldom used. The drawing, however, illustrates an important characteristic of a Mercator chart. The scale of the chart increases as the latitude scale at the right of the drawing increases. If an area of the earth’s surface be represented by a 1-inch square figure on the chart at the equator, an equal area at 60° N or S on the same chart will appear as a 2-inch square. On the drawing Greenland looks as large as South America. Actually, the area of our southern neighbor approximates ten times that of Greenland.
    Rhumb lines or Mercator tracks. Any straight line on a Mercator chart is a rhumb line as, for example, the line from A to B on the chart in Fig. 1103.
    http://i202.photobucket.com/albums/aa305/FishersofMen/1103.png
    Note the most important and useful property of a Mercator chart. A rhumb line between two points crosses each meridian at the same angle, which is the true course to steer continuously from one place to the other. All courses plotted on coastwise charts are rhumb lines, and the course to steer remains unchanged all the way along the rhumb line or Mercator track from A to B.
    Theoretically, a rhumb line is seldom the shortest track between two points because, with rare exceptions, it is actually a curved line on the earth’s surface, be its curvature ever so small. Because a rhumb line may not be the shortest track, mariners sometimes follow a series of rhumb lines which approximate a great circle, along which lies the shortest course from one port to another. (comment: we may discuss more on this later).
    Great circle tracks. The coastwise man, dreaming of voyages to foreign climes, may easily understand the principles of great circle sailing.
    Stretch a string or an elastic band between any two points on a globe; it will represent the great circle track which is the shortest distance between the points. On certain long voyages the distance saved by great circle sailing is of importance. This fact and one other characteristic of a great circle course may be illustrated, with a globe, by considering the somewhat extreme case of a voyage from Sydney, Australia, to Valparaiso, Chile. (See Fig. 1105.)
    http://i202.photobucket.com/albums/aa305/FishersofMen/1105.png
    Hold a piece of string which does not stretch, in a straight line on the globe from Sydney to Valparaiso. This string will pass south of New Zealand and slightly below the parallel of 60° S. Cut the string so that its length measures the distance between the two ports. Place one end of this measuring string at Sydney, and apply it to the globe so as to “run down the latitude” toward Valparaiso on a rhumb line or Mercator track, about 3°.5 below and parallel to the line on the globe which represents 30° S latitude. The string will not reach Valparaiso by almost 800 miles, which represent the saving in distance by approximating the great circle track on which the length of the string was measured.
    Again stretch a string, or better an elastic band, along the great circle from the one port to the other. Note that the initial course from Sydney will be toward the SE quarter but will continually change as the track crosses each meridian until, on approaching Valparaiso, the course will be toward the NE quarter. This is a radical illustration of the general fact that whenever great circle sailing is of practical advantage a ship must change its course from time to time in a manner to approximate the great circle track.
    There are no practical advantages in great circle sailing under certain circumstances, which are:
    For relatively short distances in any direction, as when sailing coast- wise; since the rhumb line is almost coincident with the great circle track, the possible saving in distance is nil and great circles may be forgotten.
    Along meridians which are themselves great circles extending north and south from pole to pole; when the course approximates N or S, there is no saving in distance between two places near the same meridian.
    Within the tropics the true map as shown on a globe is almost a Mercator chart; the equator is both a great circle and a rhumb line as are the meridians; the parallels of latitude near the equator are almost rhumb lines. In these regions rhumb line sailing is very nearly as short as great circle sailing.
    Summarized in a reverse manner: Great circle sailing is most advantageous when sailing a long voyage east or west in relatively high latitudes.
    Atlantic coast yachtsmen are familiar with two such examples: (1) The track of 628 miles of 1460 true from Newport to St. David’s Head, Bermuda, is only a hair shorter if measured on a great circle. (2) On the other hand, a great circle course across the North Atlantic to Europe is materially shorter than any rhumb line course. The victory of Olin Stephens’ yawl Dorade in the transatlantic race of 1931 was partly due to the fortunate outcome of her owner’s decision to approximate a great circle course.
    Great circle charts furnish a simple graphic method for determining a great circle track. They are so constructed that a straight line between any two points on the chart represents the great circle track. Such a line between two ports of departure and destination at once indicates whether it passes clear of danger or through latitudes which should be avoided at the time of a proposed voyage. Having considered the contingencies, one or more straight lines may be drawn to represent the desired track or tracks.
    To attain these useful characteristics, a great circle chart is constructed on the so-called gnomonic projection. Neither meridians nor parallels of latitude appear as parallel lines, and neither courses nor distances can be taken directly from such a chart. However, the charts are arranged so that it is a simple matter to take off the latitude and longitude of several intermediate points on a great circle. These points are then plotted on a Mercator chart; and joined by straight lines which are a series of rhumb lines approximating the selected track. Course and distance represented by each rhumb line are determined as on any Mercator chart. The total distance via these rhumb lines will be only slightly greater than the distance along the great circle.
    The nature and use of great circle charts and their relation to Mercator charts are illustrated in Fig. 1105 http://i202.photobucket.com/albums/aa305/FishersofMen/1105.png
    which diagrams various courses from Sydney to Valparaiso. It is assumed that the shipmaster, out of Sydney, desires to approximate a great circle track because it is shorter and because it takes the ship into the prevailing westerlies of the southern seas. On the great circle chart a straight line from Sydney to Valparaiso represents the great circle track and shows that it clears the southern end of New Zealand but passes below 60 degrees S. To avoid the dangers of such a low latitude, it is decided not to go below 55 degrees S, an assumption which serves the purpose of the illustration. A more probable course would be through Cook Strait between the New Zealand islands.
    In the case illustrated, seven rhumb lines are assumed which approximate the great circle track except that the track does not go below 55 degrees S. Each position where course is changed is marked in exactly the same latitude and longitude on either chart. The proposed track is correctly plotted on both charts, as are the great circle and Mercator tracks, although each track has an entirely different appearance when transferred from one chart to the other. The Mercator chart shows the great circle track as a much longer line than the rhumb because on such a chart one inch at 60° S measures only three-fifths as many miles as at 30° S.
    Great circle charts have robbed great circle sailing of its mathematical mysteries. The initial great circle course and the great circle distance between any two points may be computed, but for the practical business of great circle sailing the modern mariner uses great circle charts. The student who wishes to pursue this subject should procure one or more such charts and the corresponding Mercator charts.
    Various charts. Ocean charts and coastwise charts in general use are on Mercator’s projection, and are scaled by nautical miles. Charts of the Great Lakes and other inland waters use a statute mile scale. (comment: depends where you get the chart from) Ocean charts are on small scales; they show lines of equal variation, steamer tracks, ocean currents, and other general information; only the true compass rose is printed on these charts. Coastwise charts show details on various larger scales and have a magnetic compass rose inside the true rose. There are a variety of special charts, mostly on Mercator’s projection, whose titles as listed in the chart catalogs indicate their various purposes. Pilot charts for the different oceans contain an amazing variety of information, including the average weather conditions and other useful data. Nowhere can an oceangoing sailorman learn more than from a pilot chart.
    Small-craft charts. Of major interest to yachtsmen are the NOS small-craft charts now available. These charts are designated by the letters “SC” following the chart numbers.
    The small-craft charts are issued already folded and are designed for ease of reference and plotting in cramped quarters. They stress the details appreciated by operators of small craft, such as large-scale in sets of small-boat harbors, tide and tidal current tables, weather data, whistle signals, facilities at marinas, suitable anchorages, and often-used courses and distances.
    Small-craft charts are available for many areas such as Long Island Sound and the Chesapeake Bay and rivers such as the Potomac and Rappahannock Rivers, commonly used by small boats. These charts are especially useful for craft cruising the important Intracoastal Waterway.
    Plotting sheets are blank charts for use instead of regular nautical charts. They are used when the scales of available ocean charts are too small for practical plotting or when it is desired to plot celestial lines of position without marking up the regular chart. Plotting sheets printed and issued by DMAHC show meridians and parallels drawn on the Mercator projection and include one or more compass roses.
    Homemade plotting sheets for limited areas are easily constructed with sufficient accuracy for plotting part of a day’s work at sea or for plotting problems. Uniformly ruled paper facilitates their construction, although one, may rule the paper for himself.
    The method of constructing a small area plotting sheet is shown in Fig. 1108
    http://i202.photobucket.com/albums/aa305/FishersofMen/1108.png
    which represents the middle portion of the proposed layouts. Assume that the center of the work you expect to plot is in about 40° N and 70° W. Label a vertical line down the center of the sheet as 70° W. Draw a horizontal line across the middle and label it 400 N. In the drawing, each space between the vertical lines represents 1’ of longitude; therefore label each 10’ of longitude as shown.
    To locate a 10’ parallel of latitude according to Mercator’s projection, draw a line from the center at an angle to the horizontal equal to the middle latitude, in this case 40°. The length of this diagonal intercepted between two meridians 10’ apart is then the length of 10’ of latitude. With this distance, space, rule and label as many 10’ parallels as the problem requires or the paper permits. The graduations of the diagonal line marked by the 1’ meridians give the scale of miles to be used all over the plotting sheet.
    There are numerous variations of the above procedure. In any case, the point to remember is to draw the diagonal at an angle with the horizontal equal to the middle latitude of the area to be represented and thus find the latitude scale. The method is not a mere school room fancy, and is often used to plot situations in the navigator’s work book.
    To construct a Mercator chart. The above methods are theoretically correct at the equator and sufficiently accurate for all small plotting sheets. If the navigator ever should need to construct a Mercator chart of large areas beyond the Tropics, the method of meridional parts given in Bowditch should be used.
    All charts published are identified by number sometimes prefixed by letters; as “SC” for the small-craft charts. FIG. 1108. HOMEMADE PLOTTING SHEET.
    Notices to Mariners. Notice to Mariners, a weekly pamphlet prepared by DMAHC and the U. S. Coast Guard, contains notices of changes in lights, buoys, and other aids to navigation including radio which have occurred throughout the world. Notice to mariners is divided into three sections. Section I has corrections to charts, coast pilots, sailing directions, catalogs and paste on chartlet corrections. Also listed are new charts and publications, depth tabulations and hydrographic notes. Section II has corrections to light lists, radio navigational aids and other publications. Section III contains radio broadcast warnings and lists those warnings which are still effective from previous notices.
    The DMAHC also publishes at intervals of about six months a summary of corrections in two volumes which assists the navigator in maintaining up-to-date charts, sailing directions and coast pilots. Volume 1 covers the Atlantic, Arctic and Mediterranean seas. Volume 2 covers the Pacific, Indian and Antarctic seas.
    A listing of changes in local aids issued by the Commandant of each Coast Guard District on request is usually sufficient for many mariners who only operate locally.
    Careless mariners may not record all of these changes on an extensive set of charts, but the arrangement of the Notices is simple and permits noting at a glance important changes in any particular area. All charts are stamped near the lower left-hand corner with the date to which they have been corrected before issue from Washington. Dealers do not correct charts and the purchaser should insist that the date of correction be reasonably recent.
    Care on small vessels. A good chart desk with drawers is desirable and, when possible, should be within speaking distance of the helmsman. Rolled charts are a nuisance but ideal conditions for filing charts flat without folding may be impracticable. A drawer 37 X 25 >< 3 inches, inside, will take the largest charts folded once, and will accommodate about 75 charts, assuming an average proportion of smaller charts that need not be folded. Fold the charts map side out. Mark the chart number on both sides at the right-hand corner next the folded edge, which should be toward the front of the drawer. File in numerical order; keep the chart catalogs handy and from their index maps select the required chart by number. A drawer of half the above size evidently will hold any chart folded twice, and if drawers are not available vertical files folded against a bulkhead or flat racks under the deck beams will avoid rolling. A plastic case about 25 X 21 inches with transparent sides is useful for protecting the chart on deck and keeping it from blowing away.
    Charts are the most important tools of the navigator other than the compass itself. Present-day charts are the result of decades of work by the principal governments of the world, among which the United States and Great Britain have been the leaders. The meaning and use of the infinite detail appearing on modern charts will be discussed later. It is not sufficient partially to understand a chart. The navigator must train himself to interpret the meaning of every mark on a chart and to convert every detail he observes along the coast or at sea into the symbols and the terms used on charts.
    We that are going on Lake Erie fishing normally do not do all of these things. Having local knowledge of a familiar area is one thing. But I guarantee you that the experienced Captains are always on top of there surroundings mentally and know where they are at every given moment. They also have had the training that is being brought to you here; these captains have the knowledge and experience necessary to make judgment calls on the spot.
    It is a good idea to keep a chart on board if you need it or not. If electronics go down, advection fog sneaks up on you for example and no visible landmarks regardless if you are trying to get home or call for help if you are broke down, you have to know or figure out where you are.
    We will discuss more on chart reading and time/speed/distance next post.
     
  7. Fishers of Men

    Fishers of Men Senior Member

    I guess it's a good time for questions and or input. Thanks
     
  8. fugarwi7

    fugarwi7 Lumberjack

    Whew Fishers!!.....I think I'll just turn on my GPS, plug in a "Goto" waypoint, and fiddle with my tackle along the way, periodically glancing at my compass just in case the GPS goes on the fritz!! :D

    Just kidding with ya...this will be good reading as the winter progresses. And by next spring, I can sell all of my electronics and buy more tackle! :D :D
     
  9. Fishers of Men

    Fishers of Men Senior Member

    :) Hope your compass doesn't die. lol. Keep up with it...it's gonna get better when we start putting this stuff into fishing! Everyone is probably wondering whats it got to do with the fish? Well, we will have to wait and sea. pun intended :)
     
  10. FISHONAJ

    FISHONAJ wishin i was fishin

    380
    0
    471
    Good read Van ~ you obviously know your stuff. I'll keep checking back as i want to learn more about how all this is gonna get me on more :B

    AJ
     
  11. Fishers of Men

    Fishers of Men Senior Member

    I would like to discuss charts first to make sure everyone has an understanding of them. This way we can start a voyage together on here. Even the best chart is of little value if the mariner is not thoroughly familiar with the various conventions and symbols used in it's compilation. Charting is a dynamic rather than a static activity. Over time charts need to be revised. ( you saw the magnetic forces about the Earth and the Earth is always changing)
    There are many types of charts, you can go to the NOAA website to see these. The purpose of a nautical chart is to provide information necessary to promote safe and efficient marine navigation. The time-honored application of a chart is to provide data that can be used the navigator to fix the vessels position, for example, by taking visual bearings on charted natural and artificial features or ATONs. The fix might be used directly or as a check on the vessels position determined by other means, such as an electronic fix read from a loran or gps reciever. As important as nautical charts are for position fixing, the real utility of a chart lies elsewhere-in orienting the mariner. A position fix merely answers the question "where am I?" But often a more relevent question is "what does it mean to be here?" From a decision theoretic perspective, "here" should not be described by the conventional coordinates of latitude and longitude, but rather in terms of the relevant features of the surroundings and their implications for underway decision making. Charts help answer numerous key questions. Is "here" in the vicinity of rocks, shoals, ledges, reefs, tide rips, sunken wrecks or other potential hazards to navigation which should be avoided? Is "here" on the vicinity of a danger area, prohibited area, TSS or other regulated area? Is "here" near a planned turn point, waypoint or destination? Is here a place where I can anchor safely, and if so, which anchor should I use to maximize my holding power? Is "here" along my intended route, or should I make course adjustments to get back on track? And if "here" is on the desired track, am I on/ahead/behind schedule? If as a result of some unforeseen contingency ( e.g., medical emergency, mechanical problem, fuel shortage), I need to select an alternate destination, how could I reach this alternate efficiently? In short nautical charts furnish information critical to enroute decision making. I see some members calling charts "maps". In a prior post, I mentioned charts are NOT maps. Here's why: Although certainly related, the key difference between a nautical chart and a map is that the chart provides information relevant to marine navigation, whereas the map is oriented to the terrestrial user. The nautical chart differs considerably from the topographic map in it's treatment of the coastline. The topographic map emphasizes the land forms and the representation of relief, with shoreline as an approximate delineation of the water line at mean sea level. In contrast, the nautical chart has such an unique requirement for detailed and accurate representation of the coastline and water forms that it must be considered in a separate category than topographic maps in any discussion of coastal geography. These so important "Aids" show depth contours, soundings, lights, bouys, tss, channels, radio beacons, loran towers, ranges, wrecks, shoals, obstructions, piers, piles, ramps, cable and pipeline areas, bridges, harbors, type of bottom, buildings, tanks, landmarks, distances, anchorage areas, tides, currents, and other related features I probably forgot!

    I am going to hit all this info in shorter segments so it can all sink in, plus I need time to think about it :) I wouldn't mind seeing a lil more response to see if I am wasting my time or not. Only had 1/2 doz mails. You can post here. I will try to put up chart inserts but it would help if you have one to look at as we go along. I will give you all the definitions and such that is on them, explain how to read them, yes those different colored areas do mean something. Hopefully I can get something up that will print out.
     
  12. Doctor

    Doctor CJ Cat Attack Pack

    This is very interesting, you have my attention please keep on.........Thanks.............Doc
     
  13. Fishers of Men

    Fishers of Men Senior Member

    This should print out, copy and paste to word I guess!

    INDEX OF CHART ABBREVIATIONS
    (Section V of Chart No. 1)
    Abbreviation ........ Meaning ...........................Symbol
    (if applicable)
    ___________________________________________________
    A
    AERO, Aero .. Aero light ..................................... P 60
    AERO RBn ... Aeronautical radiobeacon............ S 16
    Aero RC........ Aeronautical radiobeacon............ S 16
    Al ..................Alternating.............................. P 10.11
    ALP .............. Articulated Loading Platform ....... L 12
    Alt .................Alternating.............................. P 10.11
    Am................Amber ...................................... P 11.8
    anc ............... Ancient ........................................O 84
    ANCH, Anch .Anchorage ........................ N 20, O 21
    approx .......... Approximate ................................O 90
    Apprs ............ Approaches .................................O 22
    B
    B ................... Bay, bayou ....................................O 4
    Bdy Mon ....... Boundary monument ................... B 24
    bk ................. Broken .........................................J 33
    Bkw .............. Breakwater ................................. F 4.1
    Bl .................. Blue.......................................... P 11.4
    BM ................Bench mark ................................. B 23
    Bn ................. Beacon ..........................................O 4
    Bn Tr ............. Beacon tower ................................O 3
    Br .................. Breakers ..................................... K 17
    brg ................Bearing ....................................... B 62
    brk ................Broken .........................................J 33
    Bu ................. Blue.......................................... P 11.4
    C
    c ................... Course .........................................J 32
    C................... Can, cylindrical............................Q 21
    C................... Cove .............................................O 9
    CALM ...........Centenary Anchor Leg Mooring... L 16
    Cas ............... Castle ....................................... E 34.2
    Cb................. Cobbles ..........................................J 8
    Cbl ................Cable .......................................... B 46
    Cd................. Candela ...................................... B 54
    CD ................Chart datum .................................. H 1
    Cem.............. Cemetery .................................... E 19
    CG................Coast Guard station .................... T 10
    Chan .............Channel ......................................O 14
    Ch. ................Church ...................................... E10.1
    Chy ............... Chimney ...................................... E 22
    Cl ..................Clay................................................J 3
    CL ................. Clearance ......................... D 20, D 21
    cm ................Centimeter(s) .............................. B 43
    Co.................Coral ............................................ J 10
    Co rf .............Coral reef ....................................O 26
    Cr .................Creek ............................................O 7
    Abbreviation ........ Meaning ...........................Symbol
    (if applicable)
    ___________________________________________________
    Appendix B&#8211;Abbreviations B&#8211;1
    B.2 NOAA Chart User's Manual
    PART I. INDEX OF ABBREVIATIONS (Section V of Chart No. 1)
    _____________________________________________________________________________________________________
    Abbreviation ........ Meaning ...........................Symbol
    (if applicable)
    ___________________________________________________
    Abbreviation ........ Meaning ...........................Symbol
    (if applicable)
    ___________________________________________________
    crs ................Course .........................................J 32
    Cup, Cup. ..... Cupola ..................................... E 10.4
    Cus Ho ......... Customs House .......................... F 61
    Cy ................. Clay................................................J 3
    D
    D................... Destroyed ...................................O 94
    Destr ............. Destroyed ...................................O 94
    dev ............... Deviation ..................................... B 67
    DIA, Dia ........ Diaphone..................................... R 11
    Dir ................. Direction ............................. P 30, P 31
    dist ................Distant.........................................O 85
    dm ................Decimeter(s) ............................... B 42
    Dn. ................Dolphin........................................ F 20
    Dol. ...............Dolphin........................................ F 20
    DW ............... Deep Water route ........ M 27.1, N 12.4
    DZ ................Danger Zone ...............................Q 50
    E
    E ................... East, eastern ............................... B 10
    ED ................Existence doubtful .......................... I 1
    E E Z .............. Exclusive Economic Zone ........... N 47
    E Int .............. Equal interval, isophase ........... P 10.3
    Entr ............... Entrance .....................................O 16
    Est ................Estuary........................................O 17
    exper ............ Experimental ...............................O 93
    Explos .......... Explosive .................................... R 10
    Exting, exting Extinguished ............................... P 55
    F
    f .................... Fine ..............................................J 30
    F ................... Fixed ........................................ P 10.1
    Fd ................. Fjord ..............................................O 5
    F Fl ............... Fixed and flashing .................. P 10.10
    FISH ............. Fishing ........................................ N 21
    F l .................. Flashing ................................... P 10.4
    Fla ................Flare stack ................................... L 11
    fm ................. Fathom ........................................ B 48
    fms ............... Fathoms ...................................... B 48
    fne ................Fine ..............................................J 30
    Fog Det Lt..... Fog detector light ........................ P 62
    Fog Sig ......... Fog signal ..................................... R 1
    F P ................. Flagpole ...................................... E 27
    FS, FS. ......... Flagstaff ...................................... E 27
    ft ................... Foot, feet ..................................... B 47
    G
    G .................. Gravel ............................................ J 6
    G .................. Green ....................................... P 11.3
    G .................. Gulf ...............................................O 3
    Gp Fl ............ Group flashing .......................... P 10.4
    GP Occ......... Group occulting ........................ P 10.2
    H
    h ................... Hard .............................................J 39
    h ................... Hour ............................................ B 49
    H................... Pilot transferred by helicopter..... T 1.4
    HAT .............. Highest astronomical tide .............. H 3
    Hbr Mr .......... Harbormaster .............................. F 60
    Historic Wk ... Historic wreck ............................. N 26
    Hk ................. Hulk............................................. F 34
    Hor ............... Horizontally disposed .................. P 15
    Hor Cl ...........Horizontal clearance ................... D 21
    Hosp ............. Hospital .................................... F 62.2
    hr .................. Hour ............................................ B 49
    hrd ................Hard .............................................J 39
    I
    IALA ............. International Association of
    .....................Lighthouse Authorities ...............Q 130
    in .................. Inlet ..............................................O10
    Intens ........... Intensified.................................... P 45
    Int Qk Fl ........ Interrupted quick flashing ......... P 10.6
    IQ ................. Interrupted quick flashing ......... P 10.6
    Appendix B.Abbreviations. B.3
    PART I. INDEX OF ABBREVIATIONS (Section V of Chart No. 1)
    ____________________________________________________________________________________________________
    Abbreviation ........ Meaning ...........................Symbol
    (if applicable)
    ___________________________________________________
    Abbreviation ........ Meaning ...........................Symbol
    (if applicable)
    ___________________________________________________
    I Qk Fl ...........Interrupted quick flashing ......... P 10.6
    Iso ................Isophase .................................. P 10.3
    IUQ............... Interrupted ultra quick .............. P 10.8
    K
    km ................Kilometer(s)................................. B 40
    kn ................. Knot(s) ........................................ B 52
    L
    L ................... Loch, lough, lake ...........................O 6
    Lag ............... Lagoon ..........................................O 8
    LANBY.......... Large AutomaticNavigationalBuoy ... P 8
    Lat, lat ...........Latitude ......................................... B 1
    LASH ............ Lighter aboard ship ...................G 184
    LAT ............... Lowest astronomical tide ............... H 2
    Ldg ............... Landing ....................................... F 17
    Ldg ............... Leading ....................................... P 21
    Le ................. Ledge ..........................................O 28
    L Fl ............... Long flashing............................ P 10.5
    Lndg ............. Landing ....................................... F 17
    LNG.............. Liquified natural gas ..................G 185
    Long, long ..... Longitude ...................................... B 2
    LOP .............. Line of position .......... S 21, S 31, S 41
    LPG .............. Liquified petroleum gas .............G 186
    L S S .............. Life saving station ....................... T 12
    Lt .................. Light .............................................. P 1
    Lt Ho ............. Lighthouse .................................... P 1
    Lt V ............... Light vessel ...................................O 6
    M
    m.................. Meter(s) ...................................... B 41
    m.................. Minute(s) of time ......................... B 50
    m.................. Medium (in relation to sand) ......... J 31
    M.................. Mud, muddy ...................................J 2
    M.................. Nautical mile(s) ........................... B 45
    mag .............. Magnetic ..................................... B 61
    MHHW.......... Mean higher high water ............... H 13
    MHLW...........Mean higher low water ................ H 14
    MHW ............ Mean high water ........................... H 5
    MHWN.......... Mean high water neaps ............... H 11
    MHWS .......... Mean high water springs ............... H 9
    Mi ................. Nautical mile(s) ........................... B 45
    mn ................Minute of time ............................. B 50
    Mk ................Mark ..........................................Q 101
    MLHW .......... Mean lower high water ................ H 15
    MLLW ...........Mean lower low water ................. H 12
    MLW .............Mean low water ............................. H 4
    MLWN...........Mean low water neaps ................ H 10
    MLWS ...........Mean low water springs ................ H 8
    mm ............... Millimeter(s) ................................ B 44
    Mo ................Morse ....................................... P 10.9
    MON, Mon,
    Mon. .......... Monument .......................... B 24, E 24
    MSL .............. Mean sea level .............................. H 6
    Mt ................. Mountain .....................................O 32
    Mth ............... Mouth ..........................................O 19
    N
    N................... North, northern .............................. B 9
    N...................Nun .............................................Q 20
    NE ................Northeast .................................... B 13
    NM................Nautical mile(s) ........................... B 45
    N Mi .............. Nautical mile(s) ........................... B 45
    No.................Number .................................... N 12.2
    NP ................Neap tide..................................... H 17
    NW ............... Northwest .................................... B 15
    NWS SIG
    S TA ...........Weather signal station ................. T 29
    O
    Obsc .............Obscured .................................... P 43
    Obscd ...........Obscured .................................... P 43
    Obs spot ....... Observation spot ......................... B 21
    Obstn............ Obstruction ............... K 40, K 41, K 42
    B.4 NOAA Chart User's Manual
    PART I. INDEX OF ABBREVIATIONS (Section V of Chart No. 1)
    _____________________________________________________________________________________________________
    Abbreviation ........ Meaning ...........................Symbol
    (if applicable)
    ___________________________________________________
    Abbreviation ........ Meaning ...........................Symbol
    (if applicable)
    ___________________________________________________
    Obstr ............ Obstruction ................................. K 41
    Oc................. Occulting .................................. P 10.2
    Occ............... Occulting .................................. P 10.2
    Occas ...........Occasional .................................. P 50
    ODAS ...........Ocean Data Acquisition System ..Q 58
    Or ................. Orange ..................................... P 11.7
    P
    P ................... Pebbles ..........................................J 7
    P ................... Pillar ............................................Q 23
    PA................. Position approximate ..................... B 7
    Pass ............. Passage, pass ............................O 13
    PD ................Position doubtful............................ B 8
    PTL STA ....... Pilot station ................................... T 3
    Pk ................. Peak ............................................O 35
    Post Off ........ Post office ................................... F 63
    Priv, priv ........ Private............................... P 65, Q 70
    Prod. well ......Production well ............................ L 20
    PROHIB........ Prohibited ................ N 2.2, N 20, N 21
    Pyl ................Pylon ........................................... D 26
    Q
    Q .................. Quick........................................ P 10.6
    Qk Fl............. Quick flashing .......................... P 10.6
    R
    R ................... Coast radio station
    .....................providing QTG services .............. S 15
    R ...................Red .......................................... P 11.2
    R ................... Rocky .............................................J 9
    Ra................. Radar reference line................... M 32
    Ra (conspic) . Radar conspicuous object ............. S 5
    Ra Antenna ... Dish aerial ................................... E 31
    Racon ...........Radar transponder beacon ........... S 3
    Radar Sc. ..... Radar scanner ......................... E 30.3
    Radar Tr. ....... Radar tower ............................. E 30.2
    Radome, Ra
    Dome ........ Radar dome ............................. E 30.4
    Ra Ref .......... Radar reflector .............................. S 4
    RBn .............. Circular radiobeacon ................... S 10
    RC ................Circular radiobeacon ................... S 10
    Rd................. Roads, roadstead ........................O 22
    RD ................Directional radiobeacon .............. S 11
    RDF .............. Radio direction finding station ..... S 14
    Ref. ............... Refuge ......................................Q 124
    Rep............... Reported ........................................ I 3
    Rf .................. Reef ............................................O 26
    RG................Radio direction finding station ..... S 14
    Rk ................. Rocky .............................................J 9
    Rky ............... Rocky .............................................J 9
    R Mast .......... Radio mast .................................. E 28
    Ro Ro ........... Roll on Roll off ............................. F 50
    R Sta ............ Coast radio station
    .....................providing QTG services .............. S 15
    R Tower ........ Radio tower ................................. E 29
    Ru................. Ruins................................. D 8, F 33.1
    RW ............... Rotating radiobeacon .................. S 12
    S
    S ................... Sand ..............................................J 1
    S ................... South, southern ........................... B 11
    S ................... Spar, spindle ...............................Q 24
    s ................... Second of time ............................ B 51
    SALM ...........Single Anchor leg Mooring .......... L 12
    SBM ............. Single Buoy Mooring ................... L 16
    Sc ................. Scanner ................................... E 30.3
    Sd ................. Sound .........................................O 12
    SD ................Sounding doubtful .......................... I 2
    S E ................Southeast .................................... B 14
    sec................Second of time ............................ B 51
    sf .................. Stiff ............................................... J 36
    sft ................. Soft ..............................................J 35
    S H ................Shells ...........................................J 12
    Shl ................Shoal...........................................O 25
    S i .................. Silt ..................................................J 4
    so ................. Soft ..............................................J 35
    Appendix B.Abbreviations. B.5
    PART I. INDEX OF ABBREVIATIONS (Section V of Chart No. 1)
    ____________________________________________________________________________________________________
    Abbreviation ........ Meaning ...........................Symbol
    (if applicable)
    ___________________________________________________
    Abbreviation ........ Meaning ...........................Symbol
    (if applicable)
    ___________________________________________________
    Sp ................. Spring tide ................................... H 16
    S P ................Spherical .....................................Q 22
    Sp. ................Spire ........................................ E 10.3
    Spipe ............ Standpipe .................................... E 21
    SPM ............. Single point mooring ................... L 12
    S S ................Signal station .............................. T 20
    st .................. Stones............................................ J 5
    stf ................. Stiff ............................................... J 36
    stk................. Sticky ...........................................J 34
    Str ................. Strait ...........................................O 11
    Subm ............ Submerged .................................O 93
    Subm piles .... Submerged piles ...................... K 43.1
    Subm ruins ... Submerged ruins ...................... F 33.2
    sy.................. Sticky ...........................................J 34
    SW ............... Southwest ................................... B 16
    T
    T ................... True ............................................ B 63
    t .................... Metric ton(s) ................................ B 53
    Tel ................. Telephone, telegraph ................... D 27
    Temp, temp ... Temporary ................................... P 54
    T k ................. Tank ............................................ E 32
    Tr, Tr., TR......Tower .............................. E 10.2, E 20
    T T ................. Tree tops .....................................C 14
    TV Mast ........ Television mast ........................... E 28
    TV Tower ......Television tower .......................... E 29
    U
    Uncov ...........Uncovers ..................................... K 11
    UQ................Ultra quick ................................ P 10.8
    V
    v ...................Volcanic ....................................... J 37
    var ................Variation ...................................... B 60
    Vert ...............Vertically disposed ...................... P 15
    Vert Cl ...........Vertical clearance ........................ D 20
    Vi ..................Violet ........................................ P 11.5
    Vil .................Village ........................................... D 4
    VLCC............Very large crude carrier .............G 187
    vol .................Volcanic ....................................... J 37
    VQ ................Very quick ................................ P 10.7
    V Qk Fl .........Very quick flash ........................ P 10.7
    W
    W..................West, western ............................. B 12
    W..................White........................................ P 11.1
    Wd ................Weed ........................................ J 13.1
    WGS .............World Geodetic System .............. S 50
    Whf ...............Wharf .......................................... F 13
    WHIS, Whis .. Whistle ........................................ R 15
    Wk ................Wreck ............ K 20&#8211;23, K 26&#8211;27, K 30
    Y
    Y ................... Yellow....................................... P 11.6
     
  14. Fishers of Men

    Fishers of Men Senior Member

    With the understanding of how to read a chart besides the navigational part, you can pick areas that you will want to concentrate on your fishing trip tomorrow. Take some guess work out of the boat ride, we all get enough of that and want more fishing time, right? Where are we gonna go today? By doing some homework the night before you can cut out some "guess work". For instance, lets use walleye for now, you know what time of year it is, you know what water temperatures the fish prefers at this time, you know what the natural feed is right now and so on. Now where am I going to start out tomorrow so I'm not looking all over the place? Just read the posts??? Ahh...
    Lets first check the weather for tomorrow on every site we have available, look at different lake views (the crib cam can be deceiving because it looks toward shore) okay lets see what surface temps we have out there just for the heck of it http://www.coastwatch.msu.edu/twoeries.html and along the contour lines shown I see it changes a lot. Well I know all the elements are causing different currents, so putting an educated guess together since the wind will be southwest (wind blows from, current flows to) I believe I will go to lat something and long something and start trolling on the NE side of the contour line shown on the chart, E to W zig zagging and then if no results turn and work the S side of the line back east and see what happens. Here you have a educated plan and if the fish are there you just need to get your baits to the right depth, speed etc... Not going into tactics/methods, too much controversy. Just giving an example of how a chart comes into play. Also if the plan is left at home then your spouse, lover, girlfriend, nosey neighbor or whoever has/knows your float plan for emergency. We didn't find the fish that we thought would be here (18 miles out in our 17' mod "v"), so we look at the info available and move. Found another contour that swings around like a half circle, temps varying and fish, good. After trolling a while we decide to go to the closest harbor and eat. Look at the chart, decide where and how to get there, how far etc, look at the gps, coincide #'s to chart, and go eat. Get carried away at the restaurant/bar, the table dancers are great, lost track of time. Spouse, lover, girlfriend or nosey neighbor figured you should have been back hours ago and calls CG with your proposed float plan. But we deviated from the float plan so these guys are flyin a helicopter 20 mi from us as we leave the restaurant and see flood lights in the distance. Half way back we run out of gas and the lake is picking up big time, some how the forecasts were off about 6 hrs. Throw a sea anchor out to hold the bow in the wind and look at the chart to see if we are going to drift into any obstructions/ wrecks and such. Get on our radio to the CG on channel 16 and tell them briefly the situation. Change to channel 9 and give the particulars, What kind of boat, how many on board, life jackets are on, lat/long etc...wait...we are "making way" CG says put the anchor out so you stay there. Okay, but it's coming over the bow sometimes and our bilge pumps not working. Whadda ya mean? You don't have a second one on that vessel? ...Glad this guy at least had a radio. So much with starting out with an educated plan!
     
  15. Fishers of Men

    Fishers of Men Senior Member

    I realize that some of these things mentioned are impractical for the small boats but use what you can of it.
    EMERGENCY NAVIGATION
    Planning For Emergency Navigation
    With a complete set of emergency equipment, emergency navigation differs little from traditional shipboard navigation routine. Increasing reliance on complex electronic systems has changed the perspective of emergency
    navigation. Today it is more likely that a navigator will suffer failure of electronic devices and be left with little more than a sextant with which to navigate than that he will be forced to navigate a lifeboat. In the event of failure or destruction of electronic systems, navigational equipment and methods may need to be improvised. The officer who regularly navigates by blindly &#8220;filling in the blanks&#8221; or reading the coordinates from &#8220;black boxes&#8221; will not be prepared to use basic principles to improvise solutions in an emergency.
    [I]BASIC TECHNIQUES OF EMERGENCY NAVIGATION[/I]
    The navigator should assemble a kit containing equipment for emergency navigation. Even with no expectation of danger, it is good practice to have such a kit permanently located in the vessel.
    1. A notebook or journal suitable for use as a deck log
    and for performing computations.
    2. Charts and plotting sheets. A pilot chart is excellent for emergency use. It can be used for plotting and as a source of information on compass
    variation, shipping lanes, currents, winds, and weather. Charts for both summer and winter seasons should be included. Plotting sheets are
    useful but not essential if charts are available. Universal plotting sheets may be preferred, particularly if the latitude coverage is large. Include maneuvering boards and graph paper.
    3. Plotting equipment. Pencils, erasers, a straightedge, protractor or plotter, dividers and compasses, and a knife or pencil sharpener should be included. A ruler is also useful.
    4. Timepiece. A good watch is needed if longitude is to be determined astronomically. It should be waterproof or kept in a waterproof container which permits reading and winding of the watch if necessary without exposing it to the elements. The optimum timepiece is a quartz crystal chronometer,
    but any high-quality digital wristwatch will suffice if it is synchronized with the vessels chronometer. A portable radio capable of receiving time signals, togetherwith a good wristwatch, will also suffice.
    5. Sextant. A marine sextant should be included. If this is impractical, an inexpensive plastic sextant will suffice. Several types are available commercially. The emergency sextant should be used periodically in actual daily navigation so its limitations and capabilities are fully understood. Plastic sextants have been used safely on extensive ocean voyages. Do not hesitate to use them in an emergency.
    6. Almanac. A current Nautical Almanac contains ephemeral data and concise sight reduction tables. Another year&#8217;s almanac can be used for stars and the sun without serious error by emergency standards. Some form of long-term almanac might be copied or pasted in the notebook.
    7. Tables. Some form of table will be needed for reducing
    celestial observations. The Nautical Almanac produced by the U. S. Naval Observatory contains detailed procedures for calculator sight reduction
    and a compact sight reduction table.
    8. Compass. Each lifeboat must carry a magnetic compass. For shipboard use, make a deviation table for each compass with magnetic material in its normal place. The accuracy of each table should be checked periodically.
    9. Flashlight. A flashlight is required in each lifeboat or on each lifejacket. Check the batteries periodically and include extra batteries and bulbs in the kit.
    10. Portable radio. A transmitting-receiving set approved by the Federal Communications Commission for emergency use can establish communications with rescue authorities. A small portable radio may be used as a radio direction finder or for receiving time signals.
    11. An Emergency Position Indicating Radiobeacon
    (EPIRB) is essential. When activated, this device emits a signal which will be picked up by the COSPAS/SARSAT satellite system and automatically relayed to a ground station. It is then routed directly to rescue authorities. The location of the distress can be determined very accurately. Depending on the type of EPIRB, the signal may even identify the individual vessel in distress, thus allowing rescuers to determine how many people are in danger, the type of emergency gear they may have, and other facts to aid in the rescue. Because of this system, the navigator must question the wisdom of navigating away from the scene of the distress. It may well be easier for rescue forces to find him if he remains in one place.
    Most Probable Position
    In the event of failure of primary electronic navigation systems, the navigator may need to establish the most probable position (MPP) of the vessel. Usually there is usually little doubt as to the position. The most recent fix updated with a DR position will be adequate. But when conflicting information or information of questionable reliability is received, the navigator must determine an MPP. When complete positional information is lacking, or when the available information is questionable, the most probable position might be determined from the intersection of a single line of position and a DR, from a line of soundings, from lines of position which are somewhat inconsistent, or from a dead reckoning position with a correction for current or wind. Continue a dead reckoning plot from one fix to another because the DR plot often provides the best estimate of the MPP. A series of estimated positions may not be consistent because of the continual revision of the estimate as additional information is received. However, it is good practice to plot all MPP&#8217;s, and sometimes to maintain a separate EP plot based upon the best estimate of track and speed made good over the ground. This could indicate whether the present course is a safe one.
    Thats enough on this for now. When all this "crammed" info is pretty well understood we can get into conversations pertaining to any and all aspects. I don't expect anyone to remember all this, but some bits and pieces may come in handy someday. I cant remember a lot of it because it isn't used. Thats why I like to do this, to kinda stay on top of everything the best I can.
    Some of the topics mentioned have not been explained yet I know, but thats okay because once we touch on them, later on you'll say " I heard that somewhere before. ``
     
  16. Fishers of Men

    Fishers of Men Senior Member

    Trivia:
    Anyone know where the old saying " It's cold enough to freeze the balls off a brass monkey" came from?
     
  17. ezbite

    ezbite the Susan Lucci of OGF

    13,975
    2,299
    2,398
    somewhere cold? hahaha..:p

    just kidding. i had to take a break, im seeing double. im ready to keep going.
     
  18. dood! being a person like myself that "beleives"..... you really have my attention! give me a couple days to "absorb' all of this (while i am sober lol) and i will get back with you..............
     
  19. Fishers of Men

    Fishers of Men Senior Member

    here is a chart of Lorain Harbor, thanks to Marshall McCree.
    here's a link if it works better:
    http://i202.photobucket.com/albums/aa305/FishersofMen/lorainharbor.png

    [​IMG]
    First I will mention the colors.
    The tan area is dry land.
    The green area is an area that may or may not be under water, such as when tides flow in and out, or as we have seen lately from the low water in Lake Erie. It is an area that can flood or not. Our low water lately is from the weather we have had lately, wind pushing the water east. No they didn't open the gates all up at Niagra falls. :D A lot of people were concerned about the low water, if you look on the chart, it shows that dry ground is expected in certain areas. It will return to normal. This kind of phenomena creates currents. Water temps change erratically, warm surface water from the west gets blown east, the colder water that lies heavier will go west to replace the water and such. The bait gets moved, and naturally the predators move. These currents follow the contour lines strongly. These contour lines shown on the chart are basically E to W created by the glacier movement cutting "grooves" in the bottom of the lake.The fish could be here today/gone tomorrow. Walleye have been tracked to move 60 miles in a 24 hour period. Also the wind creates another current area. Enough on currents until we get to that I got off course and the correction is being made. Our focus right now is the chart.
    The Blue area shows shallow water depths.
    The light blue shows even shallower depths.
    White areas are deep safe water.
    If you notice, the depths change inside to outside the contour lines respectively.
    An area that is a circle indicates a shoal, shallower water and guess what? There is a current if some sort around that area no matter how minute.
    These areas can hold bait/fish.
    Notice the spoil area outside the East wall? Don't think I want to go there with out local knowledge. It is always a good move to ask a local for knowledge in a strange area.
    So for a little starter, you can see where charts are also an aid to fishing, besides navigation.
    I am going to try to find another chart to finish this episode because when I enlarge this one it gets blurry and i can't read it. No... I am sober!
    "When your draft exceeds the waters depth you are most assuredly aground"
     
  20. misfit

    misfit MOD SQUAD

    though it's supposedly not really a "proven fact",it refers to old days when cannonballs would fall off the plate where they were stacked, on the ships(monkey) due to cold temps..