I don't necessarily think it's harder , just like in rivers they tend to congregate in certain areas throughout the day depending on pray and feeding habits. In a boat you can troll around and cover a lot more water to locate, and where there is one Wiper there is often a school. On a river your more limited on wYou've definitely chosen a much harder path. I have heard that wipers are much more difficult to pattern in lakes than rivers just because there's so much open water. It shows how dedicated you are for you to able to find them on a regular basis.
ater you can cover unless you are in a Canoe or Kayak. And just like in River if they aren't feeding , they aren't feeding, but at least in a boat I can locate them with my fish finder and try to coax them into feeding (something I have read is possible but haven't quite figured out yet)