Converting a mast to a tabernacle?

[DownWest]

Well bolted is my vote, the one I made is used to raise the mast on the water, so lateral loads are noticable. A particular problem was the fixings were inside the side plates so the loads were higher. Normally they would be outside on the base. The rear hook needs to be fairly well fixed and hight adjusted, otherwise the foot of the mast will bind before it sites well. OK if the mast is light (LS) but no good if 32ft long and weighty. Hinge bolt better there.
Others take care of the side loads by fabricating chain plates that put the attachment for the shrouds in line with the pivot bolt, so the shrouds support the mast as it goes up. Usually by triangulating two chainplates.So no A frame needed.
But I guess Lakey's boat does not have the shrouds in line with the mast (no backstay) This would help the OP's MacW, as it must have a masthead rig.
BTW, The tabernacle replaced a fabricated bronze hinge arrangement that had twice distorted and dropped the mast, bit nerve making and not practicle on the water. The boat is trailed every time it is used and 'launch to sailing' is about 10 min. More time is spent parking and stashing the trailer.

Plenty of unstayed masts use tabernacles. Notable are several Bolger boats and the Norwalk Island Sharpies.
Andrew

Missed your reply, cooking and typing not good...

 

[Lakesailor]

You're right. It's a fractional rig. Good news is you can leave the cap and lower shrouds at their proper tension and it's only the forestay that needs slackening off.
It's a very light mast so theoretically you could put it up without a tabernacle or base pivot (as it has at the moment).
Trouble is when you are stood on the coachroof holding a 20ft mast at about 6ft from the bottom you suddenly realise how vulnerable you are a gust, or stumble. Dropping the mast at that moment would undoubtedly kink it. The security of a pivot is very desirable.

My Valiant 18 had a tabernacle and I made a derrick to attach on the pivot bolt and the forestay. It worked very well as that boat had a similar height mast, but is was very heavy.

There's a little website here about it (in the rain)

 

[DownWest]

Nice Boat Lakey, a tabernacle would def. make it less stressfull to raise it all. The idea of pocking around trying to get the foot into a socket would spoil my day. Esp. on a windy day. (about the styling, the forecabin could do with a different camera angle )
A

 

[TamarMike]

How offten will you need to drop your mast down? perhaps once every five years?. To lower and raise back the mast, the cost is normally about £60; The cost to make an "A" frame and the tublenuckle plus other staff will be significally more. Too much hassle for the benefits. Also, the Macwester masts were heavy sections (mine is), I would not like to drop my mast to often.

Just my thoughts, after a delay getting out of the Exeter Canal last year because the council's workmen broke the mast derrick at turf I considered all this after reading quite a few Macwesters used an A-frame to raise their tabernacle mounted masts but decided the cost and effort not really worthwhile bearing in mind the weight of the mast.

I do however miss the ability to easily drop and raise the mast, my previous lugger had a very much shorter keel stepped mast which could even be lowered at sea if necessary (only had to do that once when the halliard broke). In an idle few minutes I have even sketched out a gunter rig for the Atlanta which would howevere need a bowsprit to maintain balance ... just idle doodlings though.

 

[William_H]

Mast raising

The discussion seems to have moved to smaller masts than the OP. I would definitely recommend use of a proper A frame to raise even a small mast. You can then use your muscle to maintain the mast central as it goes up which with a fractional rig is a bit complicated to do with side tensioning devices.
My habit generally with a 27ft mast on fractional rig is to use 2 spin poles and a 2 to 1 tackle on the forestay.
I can lift the mast as high as possible on a transom mounted support then haul the nast up by the tackle while supporting it sideways. Of course it is much easier with more helpers.

Back to the original OP. A suitable sized tabernacle could be fabricated out of Al or SS from a solid piece of thick metal bent into a U shape. The base will need to be wider than the mast to allow for a radiused bend but then returning closer to meet the mast.

You may have to cut away a little of the aft edge of the mast to allow for the rotation of base forward. The pivot only needs to be about 15cms above the base. Provided adequate side support is provided.

As for the claim that a mast need come down only every 5 years. Well I seriously doubt that. Mast equipment needs maintenance. ie wind pointer, radio antenna lights halyard sheaves and halyards. If you can lower your mast you will never consider climbing again. You can lower it to a high jetty without actually removing the mast from the tabernacle.

You will find however that after lowering a mast if you want it stowed properly it will take the help of a few people to lift the base out of the tabernacle and move the mast forward.Like wise of course for your initial reinstallation. It is far easier if you can support the top of the mast from the ground or another boat as you remove from the tabernacle. (or refit)
PM me if you wan to discuss. I have had a lot of experience of all sorts of size boats re mast lowering.
good luck olewill