purchase a Boat Loading System they sell for around $150
"With these boat loading systems it's a one person operation to safely guide your craft on and off the trailer. Fully proven by thousands of boat owners in rough water, fast tidal currents and strong cross winds. Comprises two separate, spring loaded 15" arms which bolt to the rear cross member either side of the existing keel roller."
its bacislly 2 big spring loaded arms that bolt onto trailer
so all you do is stick the nose of the boat into the arms then winch the boat up
the springs will push the boat onto the rollers and will keep it on track
they sell them at most big marine shops