[Public-List] Design of derrick to raise Alberg 30 mast

[Bill Burke]

I also got tired of my local yard's extortion and built a "Chesapeake" style
set of shears for raising and lowering the mast and can add a few comments
to Don's excellent description...

I built mine of 1.5" heavy duty electrical conduit but sleeved the section
joints with a full section of 1.25" conduit.  It's just a tiny bit loose (2
wraps of duct tape at several locations take up the play snugly).  The
sleeved sections are assembled with thru-bolts.  This works well to keep the
legs in column.

I would be EXTREMELY wary of tying anything off to the dock that's also
attached to the legs.  This makes you vulnerable to something as random as a
wake from a passing inconsiderate motorboat - a tossing boat with a
dock-fixed rig on it has the potential for serious damage including bringing
the whole thing down or damaging the deck.

I built base blocks out of two laminated 2x10s with a pocket hollowed out
for the base of the legs.  These are secured to the chainplates, and I also
have an eyebolt in the base of each leg for securing it as well.

I also work with my wife, who I admit also spent a number of years on
schooners and in square rig so she's certainly competent, but I'd estimate
the job to be about half the 6 hours mentioned when you get the hang of the
process.  We have two horses that we set up on the foredeck and cockpit to
set the mast on while we're preparing to step it, and onto which we lower
it.  It is a good 200 lbs, so any additional bystanders at the yard you can
recruit to help shoulder the mast makes moving the mast alot easier.

As Don said, take it slow and safe.  It isn't rocket science though.
Bill




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