abl1111,
I used to have an old Rocket tilt trailer and never had much problem with it; the bunks were right at the outer step and seemed to guide it on pretty well. However if you are dunking the trailer too deep, the bunks will not provide as much centering force, so that may be your problem. I NEVER used to dunk the axle on mine. It was a little tough to unload sometimes, but loading was never a problem.
The Rocket was a pretty lightly built trailer, so about 20 years ago I bought a HD EZ Loader with 24 small rollers on big 1" aluminum shafts w/nylon bushings, so unloading is no problem and the only thing that gets wet is the tires. I don't even have to dunk the rims, so this trailer requires very little maintenance, even with drum brakes. However I found that there are so many "degrees of freedom" with this type of trailer that there isn't much to center the boat. If it's listing to one side in the water, it wants to come on the trailer the same way! So I tried the PVC-type of guides Fr. Frank mentioned, but they weren't stout enough. I went to the steel type with side rollers and can now load with any type of crosswind. I had them raised about 13" since this photo was taken so they contact rub rail instead of gel coat. I also added a Stoltz keel roller with a 1.5" wide notch in it to rear cross member. It helps keep the boat centered until the first batch of 8 rollers contact the hull. I've used this setup for over 20 years with no problems. Requires a power winch, but it works well, and when you're by yourself, I think it's easier than a float-on type.
