RE: RC boat launched from trailer
Provided you can drive the tractor/trailer back up the ramp, lanching is the easy part. Recovery is another story altogether.
I spent a fascinating three quarters of an hour watching some Cypriot fishermen getting a small fishing boat onto a trailer in Paphos harbour a couple of years ago. Lots of advice from the crowd that gathered. I dont speak Greek, but I think I got the gist of the replys.
When recovering a beach launched lifeboat, RNLI practice is to ground the boat, manoever the trailer into position and winch the boat bodily onto the trailer.