Re: setting boat on bunk trailer
Just to confuse things, I'll tell you how I set up my 12' aluminum boat. It's different from what others have said.
I have four rollers for the keel. One at the rear, with the usual groove at the center. I have one at the front crossbar of the trailer, again with a grooved roller. I have two others that are just cylindrical spaced between those two.
I have 4' long carpeted bunks at the frame rail positions.
I set my boat up so that it's level when sitting on all four rollers. Then, I adjusted the bunks to contact the hull fully, from end to end, with the boat level from side to side. They don't really bear any of the boat's weight, to speak of, but keep it from wobbling from side to side. The four rollers do a great job of supporting the boat and there's almost no stress on the keel, since none of them support all that much weight.
Here's my reasoning: At launch, I back the trailer in until the stern of the boat just floats off the bunks. Easy peasy lemon squeezy to shove the boat off, while holding the launch line.
For the retrieve, I back in until the rearmost roller is about 1/2" above the water surface. I drag the keel into the groove in the roller, then pull it, manually over the other two rollers with the bow rope over the center of the trailer. It's about a 25-30 lb. pull, and the groove at the rear is enough to swing the boat centered, even in a mild wind or current. I winch the rest of the way. Again, no strain, no stress, since the boat is on the rollers until it is almost to the bow stop. Fully loaded the bunks are in full contact with the flattish bottom of the boat and everything's solidly held in place.
It sure is easy to launch and retrieve, and there's really only about 50 lb. of weight on any one roller.
Just another approach you can take. It's perfectly safe for the boat, and makes the launch and retrieve as easy as can be.
