Something a marine
who used to fly the Pacific taught me "because you can see everything you drop a hundred feet down on the bottom, and there's no way to reach it" you put a lanyard on EVERYTHING that goes near the water, or in it. Yes that can be a PITA but it helps with dropped stuff. You can sometimes take some mesh (onion or potato bag) and put a frame around it, under your work area although that's often not possible.
About 1/3 of the OTC stuff works for about 1/3 of the people about 1/3 of the time (G) so it is worth trying different things. Read the ingredients, a number of the products are actually the same thing. And one of the oldest is plain ginger. You can find all sorts of ginger tea, ginger candy, even ginger capsules these days. Too much may make you burp and irritate your stomach, but it isn't just a folk remedy. The ginger is what is called a "rubefacient" it dilates the capillaries and that increases oxygenation as the bloodflow is increased to the entire body. There's objective science behind it, and if you give it 20-30 minutes to get into you before you go, that may do the trick.
But if the boat is bobbing around that much you'll probably also be knocking your head
into it. A neoprene diver's hood
, or two watch caps, helps cushion the banging.