here is a thought!
I had a boat that was hard to launch by myself. Figured how to power winch it off my roller trailer. Now have a newer trailer and bigger boat and I do fine with out my little invention. I installed a pulley on the last cross member of my trailer. It was the type with a pin so I could easily remove the center piece. At the ramp I would take my cable off and pull it out, put it through the pulley and then bring the hook back towards the winch. I then took a rope - premeasured to hook to the front boat hook ( where you normally attach the cable) and ran the rope back to the hook which was probably somewhere under my center console. This prevented the metal cable and hook from marring the out side of the boat. Push the lever to retrieve the cable and the boat moves backwards! A little complicated but does work. Draw a diagram of this before you start laughing! Here is the draw back, You will be maneuvering around the parking lot and starting down the ramp with out a firm attachment to prevent the boat from rolling prematurely. This particular trailer and old boat took half a football team to push it off, even on a good day. If you use the safety chain to prevent this and the boat slides, now you have to get the cable off to move the boat forward and start the hook up all over again. My two cents!