Where can I get a mast tabernacle?

[bob26]

Any ideas where I might find a mast tabernacle - or have one made reasonably economically?

It needs to be about 80mm wide and 400 mm tall.

I can approach metal fabricators but I wonder if these can be obtained as stock items anywhere cheaper or if there is the equivalent of a breakers yard where one might be found?

Bob

 

[William_H]

I suspect you will not get many replies because it is a bit unclear what you need. (or what your boat is like. An older style tabernacle has 2 vertical posts set 80mm apart and has a bolt for an axle about 300mm up from the deck. This enables the mast to pivot down and hopefully with slop in the pivot hole of the mast the bottom rests on the deck to take the actual load. Just how these posts are attached to the boat is a question as they may extend (with suitable spacers to make rigid) right down to the keel. Or they may be joined together above deck and have a support post underneath. You must anticipate a huge load when sailing in the downward direction. However if you lower the mast rather than lift with a crane then anticipate large forward thrust on the pivot bolt at the 45 degrees mast down position.
Bear in mind that the higher abover the deck the pivot bolt then the higher will be the mast when lowered. nice for clearing hatch cover or instrument binacle.
I am assuming you would want to be able to lower the mast yourself which has enormous advantages. Around here racing boats up to 90 ft mast lower them for bridges while underway.
Around here a popular style for up to 24 ft is a cast aluminium base with a matching plug that goes into the Al mast section with a hinge pin at the back. Unfortunately with a pivot hole in each side of the base (50mm apart) any sideways swing of the mast on the way down rips out the axle support in the base.
In this case the base screws flat onto the deck with support underneath.
My own mast base on 21fter tall mast fractional has a flat SS plate on the deck with a spine welded front to back, about 25mm high and a raised part of the spine with a hole through at the aft end. There is a slot in the base of the Al mast (a plate was welded onto the base of the mast with a slot cut) and lugs welded on to the mast at the bottom either side of the sail track. This means the pivot bolt is only 40mm long and the pivot lugs on the mast 10 mm apart with the "spine" between. The advantage is that when lowering the mast any sideways swing of the mast simply bends the lugs on the mast a little apart and in fact a large swing can be accomodated without damage.
Sorry I waffle on and this may not be of any interest at all to you. However PM me if you want more info especially on mast lowering. Because of bridges we have a lot of local experience. olewill

 

[guernseyman]

I have considered replacing my tabernacle - which provides for two bolts, the upper takes the weight, and the lower is a locating bolt to keep the mast upright when the rigging is disconnected.

There is a small firm of marine engineers here that I always turn to for SS work, and I would doubtless ask them to copy the existing tabernacle in SS. The cost would not be huge. They made a stem fitting a few years ago involving roughly the same amount of materials and work as a tabernacle, and it didn't break me.

 

[bob26]

Many thanks for this long and considered reply William.

I'm after exactly what you described first for a 30foot deckstepped mast on a 24 footer - about 380mm high x80 wide would be even better . I have one of the inverted T deck hinge types now and it is scary.

Bob

 

[ianc1200]

I got my boatyard to fabricate one two years ago for the new mizzen mast, based on a design I'd seen on a friend's sister boat, but the real problem was finding somebody to galvanise it, we're Oxfordshire, but had to send away to Peterborough

IanC

 

[William_H]

High Bob26 I imagine you find it scary because of the swing problem as you lower the mast. (There should be nothing to worry about when masty is up as tabernacle has no load except straight down) I find the advantage of the inverted T type is that it can cope with swing without damage. The problem with posts each side is that while it might seem it will resist the swing in fact because of the huge leverage it will more likely be damaged by a swing. (if it gets out of hand) ie if the boat is rolling in a mobo wake)
The swing is stopped by staying the mast sideways from a point abeam the mast hinge point so that the stays stay tight all the way down or in my case I actually tension the fractional aft swept stays forward from a point about 2ft above the chainplates and adjust the tension as it goes down. (both sides simultaneously) in calm conditions or on flat water I use a person on the cabin top holding the nast from swaying and drop it into a crutch PDQ.

In otherwords I am advocating persavere with what you have olewill

 

[Guest]

Try any of the older Baot Yards that have boat wrecks ....

I don't know if still operating - but in Southampton - Belsize Boatyard - is behind the TV station and breaks boats ....

There is always the Barge at Swanwick opposite Deacons ....

Paynes Boatyard - Thorney Island

as examples .....

I assume you are talking about the older standard tabernacle where you have two vertical faces and a box base. The base has extended plate to allow bolts down through deckhead. The two vertical faces have two through bolts .... one is to pivot the mast, second is to lock it in vertical position. These tabernacles were originally designed to carry the mast compression through the bolts with a soft keeper sometimes inserted under the mast foot to assist.

Personally I much prefer this style of mast fitting to the later Blade style, even though the tabernacle style does not allow forward rake of the mast.

To find one .... shouldn't be too hard once you have found the old yards with loads of stuff from boats that have gone to their boat-yards in the sky ....

Good luck.

 

[Guest]

Blade mast fitting ... join the club !

I too do not like the inverted T fitting ..... it may be great to allow forward rake of mast and all that .... but it gives no margin of error when raising / lowering in side movement .... I have a heavy mast on my 25ft'r which is not funny to work with.