Actually, Overstreet, you are being very conservative in taking your measurements that way and it would be easy to show much greater reduction in lifting power than that, at least for the overhead lifting, which is what really matters. In that video you posted, though the person demonstrating did start out by lifting one end overhead, there was no need for him to do it that way, though it many have been easier than holding the whole boat at waist level and on a tilt. The main thing is that once the boat was on the rollers, the balance point was all the way to the halfway point and beyond before the real need for hands-above-head lifting came about, so the lifted weight at that point was virtually zero or even negative. In the video, you could even see that the rear end of the boat was simply pulled up by the overhanging front portion, and no overhead lifting at all would have been needed if a person chose. So, you are right, but an even stronger case for greatly reduced lifting requirements can be made here.