Some boat movers have special trailer, called "Wish Bone Trailer". These
have no perminent frame down the middle.. The truck has a hydraulic hitch
that raises and lowers the whole trailer in a rocking motion. The trailer is
backed down with the longitudinal frame on either side of the boat, the a
couple side stands are set up from the trailer for support while the groud
stands are removed.. Then with some tricks with the truck hitch, the boat is
lifted off the gound, repeating this with additional keel blocks until the
keel is far enough off the ground until the trailer keel timbers can be
installed.

I've had my boat moved twice using this system and never have any problems..
My boat (13.5 ton) was at the max limit of this trailer.

Another interesting feature of this WishBone trailer. It has a frame made of
about 8" steel pipe. When he has a very heavy load, he pumps compressed air
into the frame to give it ridgitity (kinda of Viagra for boat trailer).

Normally these trailers are reserved for local hauls but if you call around
you might find one that does long hauls as well. Or you could have your boat
delivered to a local delivery yard and then have it transfered to a self
loading trailer..


--
My opinion and experience. FWIW

Steve
s/v Good Intentions