Scott Dufour wrote:

Yup.  That's definitely what I was missing.  A hinged mast with a sleeving tube, eh?

Suddenly the world makes a bit more sense.

If I went that route, I'm guessing that it would be something like:

1) Order a mast the same length as if were a normal keel stepped mast.

2) Cut the mast above the deck at about 10% of LOD.  Fabricate an internal hinge.

3) Source another section of mast with an ID = the mast's OD.

4) Sleeve this over the mast, fair the top somehow, and secure.

The numbers would look something like:

	ft
Mast total length from step	50.0
Mast length above deck (LOD)	44.0
10% of LOD (hinge height)	4.4
Mast Length above hinge	39.6
Sleeve extension above hinge	4.0
Sleeve length	8.4
Sleeve as % of LOD	19%

It's about 120 lbs of added weight with COG 4 feet above the deck, not including the hinge materials. I wouldn't have to pay somebody to design it - I can do that myself. Sourcing the sleeve might be straight forward.  The mast is tube (OD = 10"), the sleeve can be 10" Schedule 40 pipe.  Pipe ID = 10"   My mast is the max most places provide (10" OD).  I think most pipe comes in 6061-T6, so that's way more than strong enough.

I'm guessing the sleeve would cost maybe $1000 USD.  Figure another $1000 for the weld work fitting the mast hinge.

Doable. 

What d'yall think?  

in that some clubs have their own derrick that can be used by club members at a very reasonable rate, or thy hire a crane in to lift boats once or twice a year and you can slip in with that group

Scott Dufour wrote:

It may be that crane work is less expensive in the rest of the world than in Connecticut, USA.  It was $1200 USD to pull the mast from my boat 

Scott Dufour wrote:

It may be that crane work is less expensive in the rest of the world than in Connecticut, USA.

How can anyone justify that much to pull a mast?

Chris

I don't think you're giving up much Scott.  I have masts the size of yours and they come out surprisingly easy with a crane truck (assuming you have wooden wedges or a conical partners if you use something like spartite).  We laid the masts in a temporary wooden "gallows" for road transport, I think they would also have been fine like that for something like canal work.  I couldn't find my receipt for the crane truck, but it was not exorbitant.  Our driver hadn't done a mast before, but it didn't phase him in the least, I suppose a mast is a lot like a telephone pole.  If you're planning on removing the masts and laying them on deck, a stripe painted just above the centre of mass would come in handy.

David Tyler wrote:

So the question I have to ask is: why do you think a tabernacle is needed? You're talking about a mighty big, heavy stick that cannot be handled with manpower alone. Even if there's a tabernacle, it would be a major undertaking to raise and lower the mast, and i don't know how I'd do it without a crane to pull it up. Why not, then, just use the crane to step the mast?

if i understand correctly from what David has said I would agree that any mast that two big guys can not throw around is going to become a monster when you try to set it up right.

The cost of such a tabernacle with sufficient strength built in alone is going to cost.

But if you are going this way use epoxy to stick it down with, you will have to etch the alli (you can get this at a good car panel place)  then coat it with epoxy let it set off then abrade with 120 grit paper mix up your epoxy with something like celli fibres these make a very strong pudding that will bed your hardware. re drill your holes as they will fill with epoxy  but it will make a barrier between the alli and stainless metals

pete j