I was thinking a float on a carbineer , the kind of float you use on a crab trap, clip that to the sling , with the 1 inch hole through some of those , could just make up a sling with one on the sling

The salt eats everything anyways, so if I replace a cheap rifle every 5 years no matter what, I’m not attached to it in any form. And having a float dangling off my rifle doesn’t sound real handy either lol. I appreciate the ideas, but having a sacrificial skiff gun is the conclusion I came to as a teen, and it still works now.

sounds like the environment they market my 590A1 mosberg Mariner for. I'm not in salt water bought it thinking it would hold up well as my wife's van gun.. Learned battery acid on jumper cables in the sto and go can get on the aluminum receiver and pit it. I wonder if it would really hold up . Do the small internal springs rust up and causes malfunctioning?

On a boat gun anything that can rust, will rust. I haven’t ever kept a shotgun onboard unless I’m going waterfowl hunting, I usually have a 10mm on my hip (in my backpack while I’m working) and that would cover any short range needs I have, like dispatching large fish. I keep a 5.56 along because if I needed to shoot people with negative intentions, that would be the ideal tool, and I’m native, so I can shoot sea otters, and it’s excellent for that as well