I was on a trip recently with a woman who had adapted to outdoor potty needs by learning to pee while standing. Don't know if there was anything unique about the plumbing, but she'd just stand up, move here bathing suit out of the way, and pee over the side. (Granted, there was a bit of spray, but, given the alternatives, she didn't seem to mind.)

Maybe she can teach a "How to Pee at Sea" clinic someday.