This thread covers the same issues you are having. I had the same problem with my old trailer, and I solved it by fixing the bow riser. I used to have to do the same thing with my trailer as you. I'd have to back it in just right. Enough to be able to pull it up, and still get the nose up. I used to have to power onto the trailer to get it up there. I hated doing that. And if I got a real deep ramp, it was a pain in the ass. I'd look at your bow riser. It's there to get the nose up, and to provide a good support for the nose. But not to hold the weight of the boat. That's why sometimes you have to lift the bunks as well.