[TrueBlue]

Effectively using non-stabilizing binoculars on a moving boat can be challenging at times - especially if the subject is moving as well.

There's some similarity to riding a horse - where a rider will buffer the horse's galloping movement by using his legs as shock absorbers. I find it is best to stand, such as how AboardIndigo describes. With feet planted on deck, stay focused on the subject while bending the knees & waist.

Ever watch a bird sitting on a moving tree branch? His head seems fixed, while the body moves in sync to the motion effects caused by wind.