I'm kind of in the same boat so to speak. I have to ask about the draw bridge. Could you or
have you attached dock floats
http://www.overtons.com/modperl/product ... 009&r=view to the end and used these as part of a hinge
http://www.overtons.com/modperl/product ... 009&r=view. You would need a couple of piles at the end, with these attached
http://www.overtons.com/modperl/product ... 009&r=view to keep the ramp from being torn laterally. I've thought about doing this and just letting it float.
To transition from the slope angle coming out of the water to horizontal over my sea wall, I'm using a pivot system similar to a see saw. I pull the boat up the see saw 'boards' that supports the hulls. I used 1" galvanized pipe as the center axle/pivot point. As the center of gravity shifts, the boat and boards pivot down to a level position. This prevents having a single point in the hull take all the rotational stress.
One last thing you could consider is using these.
http://www.overtons.com/modperl/product ... 009&r=view Install them at the end of your bridge, but have them attached to a set of pivot arms. You'd need two winches, where one would be attached to the top of the pivot arm, and the other near the bottom by the wheel. When you want to raise the bridge, use the top winch, to lower use the bottom winch. Obviously, I'm just throwing out a simplified idea here. Using a couple of motors, cable winder, shafts and pillow blocks on shore would be the smart way to go.
Good luck