You will need to hire a metal worker/welder to begin by modifying the
trailer bed to recieve the boats keel through the bed.

(Actually if your welder/metal worker understands what you want to do, then
he is going to know how to go about it. If he doesn't then look for
another..)

I would imagine that once the trailer bed has been opened up and lowered
cross members installed, the next step would be to have the boat set into
place and blocked up so the metal work can be fitted to the boat. You want
to get these lowered cross members down to within a foot of the road surface
so you will get the require 14 ft overhead clearance.

The boat stands are available from any boat moving company for about $50
each. Boat yards have access to them as well..

The stands alone will only support the hull in a static load. You will also
need some sway bracing and tie downs.

Really the best way to see how this SHOULD be done is to to to a boat movers
yard and look at one of their trailers. Photograph it with a boat on it and
not the way their adjustable stands could be adapted for your use..

However you do this at some point you will need a crane or travel lift to
set the boat inplace for the final fitting.. You may find a boat yard that
will cooperate with this and allow your welder/metal worker to work in their
yard.

Sounds like an interesting project.. There are times that I wish I had my
own trailer for my Ingrid but then I would still have to hire a crane for
the mast and a tractor to haul the trailer. In the short term, it's cheaper
to pay a mover or a boat yard.

Good luck.

Steve
s/v Good Intentions