I always thought it had to do w/ the loud music playing, spilled beer going down the scuppers and all the banging around from the horseplay.



Actually the 1st time I took my boat tuna fishing, my friend ( an experienced tuna-man) took a bucket of water placed in the middle of the cockpit and played w/ the motor RPM & trim till he got the most vibrations or most ripples in the bucket he could get at the desired speed.
Inboards, outboards, diesel, gas or whatever I've been out there getting skunked while the bigger boats were hooked up and visa versa.
Personally I think it's just the groceries.
robert