Thanks for the responses. I've used MarineTex before when I dinged up my rudder (it's always something, isn't it?).
Caverun, that's interesting about your trailer. True, the boat rests only on the inside of the bunks in forward half. I've always found that odd, but just assumed that was the way it was supposed to be. Maybe the previous owner did a little tinkering with the bunks or the roller for some reason. Gives me another project to investigate!
The black conduit in the front is the electrical for the trailer lights.