Hi, actual Subsea Vehicle Pilot/Tech here:
Unless this thing is staying underwater for weeks at a time, you don’t need to go to any extreme measures. Especially if it’s fresh water, galvanic corrosion happens way slower In fresh , and way slower than you all think it does, even in seawater.
Like it was mentioned above, it’ll be the most vulnerable to corrosion if it’s left wet after it comes out of the water. Rinse it when it comes out, and use compressed air (even a leaf blower) to get the water out of the nooks and crannies.
We also use a lot of wd40 on surfaces we don’t want water settling on (after we hit it with the air)
we use a lot of solid bronze bushings, with ceramic on the high-speed stuff like the thruster prop shafts. You’ll probably not need to withstand 200hp at 300 rpm, so the standard bearings in the hubs/cranks will be fine. I’d pack them full of blue “trailer” grease to keep the water out. We use that on a lot out here. Adding a zerk to keep them topped off is a good idea, just so you don’t have to tear them down every time you want to add grease.
If there’s a chain involved, we like White Lightning “Epic” chain lube (mfgr recommended) or in a pinch, the white lithium grease that comes in a spray can. It’s really more about getting lube between the side plates, than on the rollers.
Good luck with the project!
