Following up on what Larry said. Most bass boats have 4 bunks on the trailer. 2 longer ones in the middle and 2 shorter ones on either side. My general guide when loading a boat I am not familiar with is back in so the front tip of the shorter bunks is just barely sticking out of the water. Then I approach the trailer at an idle and pull it out of gear just before it contacts the bunks. The boat will settle itself in the bunks. Then I make sure the motor is straight and use it to push the boat up onto the trailer until the bow loop contacts the roller. After doing this a few times, you find the sweet spot. If you have a strong cross wind or current, then put the trailer in a little shallower, then hit the bunks under power and get it settled straight, then have the trailer backed in a little further and finish pushing it up to the roller.