Molesworth wrote:
.. I have a set of cast Danforth Davits. Have blasted and painted them
and am now nearly ready to put them on the boat.

They are rated 175 lbs each.

They are going on the stern of a 39' 1980 center cockpit boat. The
fiberglass is very thick.

First, I'd like your collective input on how much/what sort of bracing
in the aft cabin to support the davits with a hardshell dinghy mounted.
I'm thinking a piece of 1/2" aluminum - to cover the space between the
davits plus 4-5" wider all round.

My rough rule of thumb for backing plates = 0.5 x fastener diameter.
1/2" is way overkill. No need to span between the davits, the middle
part of the backing plate won't be doing anything for you. Just a few
inches bigger in both directions than each davit pad.

Second, what quantity (blocks) and other type of hardware will I need?
What size line will I need? This will determine the type of block.

I'd use a 4:1 purchase at each end. Fiddle blocks. If your dinghy
weighs 100 lbs, then each purchase lifts 50 lbs. 50 lbs/4 = 12.5 lbs
so very easy to pull by hand. Use 5/16" line because 1/4" is a bit
hard on your hands. Make sure the top block has a built in cam cleat
if your davits don't have their own cleat.

Sorry to sound so dense but I'm relatively new at this and there is
no-one around here to ask. (I'm the only sailboat at the yard (all rest
are fishermen or shrimpers).

Thirdly, I've got to balance effort against price. I don't think I can
afford an electric hoist, nor do I see where it could be mounted, so a
hand winch will have to do. So, how do you get two hoist lines to go on
one winch? (I'm guessing it's a matter of more pulleys(?)

With difficulty. Easy way is to have 2 independent drums on same
shaft. How heavy is your dinghy?? Two tackles are a lot simpler.

Evan Gatehouse