Not all 4' waves are equal. I've been in big wide 4' rollers on Erie and only pick up a little splash over the bow while trolling and a tiny amount of spray at 1/2 throttle. On Lake St. Clair, the 4'ers were fairly close together white caps and we bathed at any cruising speed above idle. I have a 16' alumimum deep v starcraft which tends to ride high because the boat itself only weighs 650# without motor, console, troller, people, and gear. I would assume you will occasionally get wet in 4'ers and stow the rain suit.