Re: Completely submersing a trailer with surge brakes
I have never heard of that, if they are doing that in salt water you can expect to need a new crank probably in about a year, a brake reservoir possibly sooner, and endless grounding problems, because your ground wire is usually bolted to the trailer somewhere right behind the hitch.
I would also worry about the trailer strap loosing its rated holding strength due to the water. I'm so paranoid about keeping my tongue and crank assembly dry I wrap both in marine cloth when it is parked in my yard. Not a spot of rust on either 4yrs later.