Regarding the boat in MdR, that must have been some interesting dynamics. On the trailers I use, there's a ball hitch there which, I assume would allow the floating trailer to pivot up, not affecting the trucks rear wheels. If there's a equalizer hitch there will be some lifting, but the front brakes should hold that boat.
And in the end, the wheels of the boat were pushed up on the ramp, so that the boat is out of the water. Mabey the shot is of the boat after it's pulled up.
I'd love to have a video of the "event".
Boris