crown22
Member
Just about to make an offer on a secondhand one.My boat is an Atlanta Viking 8.5 with a mast length of approximately 30ft.Any advice appreciated.Thanks
Mast Tabernacle-Any downsides?
- Thread starter crown22
- Start date
Refueler
Well-known member
If its a proper tall tab - go for it ... I wish I had one on my 25 ... instead of that daft blade and slot pivot job.
I cannot fit one unfortunately as cleats / winch etc are too low on the mast ..
I cannot fit one unfortunately as cleats / winch etc are too low on the mast ..
Tranona
Well-known member
Is this a replacement for the original? There are many types of tabernacles so difficult to advise whether the one yyou are looking at is suitable. In general terms, make sure the plinth on which it sits is sound and that the bolts will find the holes. Use plenty of sealant to bed it down. Ensure that the installed height of the mast is the same as previously if you are using the same rigging.
rogerthebodger
Well-known member
I made a hinge and bracket to connect to my mast to allow it to be hinged down with bracket attached to the for and aft lower chain plates to provide sideways supports when lowering the mast
The mast clamps can be positioned to miss the winches
This is my mast step
The mast clamps can be positioned to miss the winches
This is my mast step
Laminar Flow
Well-known member
They can, properly built, add considerable weight at the wrong point; especially on smaller craft.
The hinge point must be high enough to clear any obstacles on deck, such as dodgers, wheelhouses etc. and for cockpit clearance if used while transiting canals etc.
On multi-masted vessels, at least one tabernacle should be "misaligned' to the centre line to make sure the masts clear one another when lowered.
It is common to have a fixed chain plate bridle to the hinge point height, to maintain load on the upper shroud for control while lowering, especially if you intend to use the setup to shoot bridges or use it when under way.
Check out images of Dutch sailing boats for inspiration.
The hinge point must be high enough to clear any obstacles on deck, such as dodgers, wheelhouses etc. and for cockpit clearance if used while transiting canals etc.
On multi-masted vessels, at least one tabernacle should be "misaligned' to the centre line to make sure the masts clear one another when lowered.
It is common to have a fixed chain plate bridle to the hinge point height, to maintain load on the upper shroud for control while lowering, especially if you intend to use the setup to shoot bridges or use it when under way.
Check out images of Dutch sailing boats for inspiration.
LiftyK
Well-known member
Ensure the base of the mast is supported by the deck and is not hanging only on the pivot pin. Failing to do so caused my mast ro adopt an hourglass shape by the pivot pin. The solution for my mast was to remove VOL-au-vent section and rivet in a replacement section, then drive a wedge between mast base and deck to support the mast from below.
Boathook
Well-known member
My 35 ft mast is in a tabernacle on my 9m cat. Not a problem in the last 45 plus years and my boat is one of 250 odd. There should be support to the keel / bulkhead to prevent the deck from sagging. The reality is that I have only used the tabernacle once to lower the mast and the other times a crane.
Stemar
Well-known member
The boat must be 30-odd years old now so, if it's original equipment and hasn't broken yet, I doubt it's going to. It may be useful it allowing you to lower the mast, but come back here and ask how before you try it. Personally, I'd use a crane if one's available.
The two boats I've owned both had tabernacles, and I've never had any issues.
The two boats I've owned both had tabernacles, and I've never had any issues.
Refueler
Well-known member
Some used a slightly tapered wood block ... many lost that and did nothing. many Tab's had two bolts not one ... so load was carried by two bolts - but they had to be proper size for the job .. not just s alight bit less diamter to make life easy.
Sounds like you suffered the 'single slightly less diameter' pin and no pad.
Ian_Edwards
Well-known member
I had a tabernacle on my Parker 275.
I used it every spring and autumn to lower an raise the mast.
As other has said it is very difficult to keep the mast on the centre line, unless you have a seriously good means of support. Either some strong well we'll trained people, or a means of keeping the shrouds tight, as the mast is lowered.
I used a block placed high up on the gable end of the clubs boat store. The sheave was about the same height as the hounds, and the sheave for the jib halyard, and used the jib halyard to lower the mast. This arrangement kept the lifting/lowering point above the mast, making it inherently stable.
I realise that this isn't always possible, but it worth looking for a strong point high up to give a better angle for the rope taking the load.
It the whole process so much easier.
I used it every spring and autumn to lower an raise the mast.
As other has said it is very difficult to keep the mast on the centre line, unless you have a seriously good means of support. Either some strong well we'll trained people, or a means of keeping the shrouds tight, as the mast is lowered.
I used a block placed high up on the gable end of the clubs boat store. The sheave was about the same height as the hounds, and the sheave for the jib halyard, and used the jib halyard to lower the mast. This arrangement kept the lifting/lowering point above the mast, making it inherently stable.
I realise that this isn't always possible, but it worth looking for a strong point high up to give a better angle for the rope taking the load.
It the whole process so much easier.
Refueler
Well-known member
A frame ... with a high sided Tabernacle - it does not have to be as strong as I have ... its only to control the lowering / raising better.
My Snap 23 ... my son at about 10yrs old with me - could lower / raise the mast with that tabernacle .. in fact I didn't have an A frame then ... we would just walk the mast down ..
Here I have strong metal poles - way overkill actually - but they were free .... I have the minimal blade / slot mount which I hate ... but cannot change due to mast fittings too low ... but the video shows how easy it is ...
Main sheets moved to bow to give the raise / lower of the frame ... spinnaker halyard to the frame ...
BUT take note that my pal made the mistake I asked him not to do ... move when mast lowering .. as the when boat is on water - it will heel and mast swings to side .. he should have stayed still and just guided the mast down to the Y support at transom .. all the weight etc is on the A frame.
I can actually raise / lower that mast on my own with that frame ...
William_H
Well-known member
OP question is not specific enough for a clear answer. "tabernacle " often means to some people an arangement for hinging the mast in the form of 2 posts from keel up through deck extending perhaps a metre above deck with mast hinged on an axle through the 2 posts. This can have the efect of holding the mast on the centre of the boat when the mast traverses down. The big problem. Although perhaps not as positive as you might hope. Depends on the width of the posts.
However "tabernacle" might mean to some the name for the hinged base of the deck stepped mast. These are much more popular in various forms. The common type being a flat plate with raised lugs at the back with a matching plate and plug in the bottom of the mast extrusion. A pin goes through the lugs to make a hinge. Unfortunately the typical spacing of lugs about 12 cms is the worst for load on the lugs if the mast is not maintained on centre line as it traverses. if as Nigel found the boat heels to one side the mast swings that way when half way down, exacerbating heel, the lugs snap off.
A single blade type arrangement has less movement on the narrow base so can with plenty of free play cope with some mast swing. (mine has survived 45 years so over 100 raise and lowerings)
Another style seen here (bridges make mast lowering mandatory) on boats with keel stepped mast is to cut the mast about 80 cms above deck and fit a hinge that can be bolted together to retain mast bending integrity.
But in all cases some sort of arrangement must be used to keep mast central all the way down. Keeping cap shrouds tight on mast head rig is good.
One inovative system here uses spin poles hinged on the rear cockpit gunwhale that attach to a car that slides up the mast track in such a way that mast is always centred as it goes down.
So just whart is OP looking at buying? Is it a replacement for an existing hinge or does he want to fit 2 posts to make a traditional tabernacle? ol'will
However "tabernacle" might mean to some the name for the hinged base of the deck stepped mast. These are much more popular in various forms. The common type being a flat plate with raised lugs at the back with a matching plate and plug in the bottom of the mast extrusion. A pin goes through the lugs to make a hinge. Unfortunately the typical spacing of lugs about 12 cms is the worst for load on the lugs if the mast is not maintained on centre line as it traverses. if as Nigel found the boat heels to one side the mast swings that way when half way down, exacerbating heel, the lugs snap off.
A single blade type arrangement has less movement on the narrow base so can with plenty of free play cope with some mast swing. (mine has survived 45 years so over 100 raise and lowerings)
Another style seen here (bridges make mast lowering mandatory) on boats with keel stepped mast is to cut the mast about 80 cms above deck and fit a hinge that can be bolted together to retain mast bending integrity.
But in all cases some sort of arrangement must be used to keep mast central all the way down. Keeping cap shrouds tight on mast head rig is good.
One inovative system here uses spin poles hinged on the rear cockpit gunwhale that attach to a car that slides up the mast track in such a way that mast is always centred as it goes down.
So just whart is OP looking at buying? Is it a replacement for an existing hinge or does he want to fit 2 posts to make a traditional tabernacle? ol'will
Marceline
Active member
Thanks for the video - we've a tabernacle on our boat's mast point and I've often wondered how its supposed to work with raising/lowering
can I ask - are you supposed to loosen the standing rigging at the sides before hand (tbh I'm not planning on doing this, more just curious) ?
Refueler
Well-known member
Yes you slack all rigging - even the aft stays ... its a strange thing - but the compression exerted by all stays causes the mast to resist pivoting. I slack mine a noted number of turns on the cap and stays that are aft of the mast base. Obviously those fwd of mast base need to be disconnected.
I leave the locking nuts in position - so I have a reference for tension when mast raised again.
Once used - an A Frame is appreciated and I will never be without again.
Marceline
Active member
cheers Refueler - I'd often wondered how people do the lowering and what happens with the standing rigging
We're possibly looking for a bigger boat (as we'd hope to venture across the channel and be able to do some canals in the future) so that's good to understand a bit more how tabernacles can work. We've seen a few boat listings with a 'mast lowering system' with a pole but weren't sure how the boats do it. One of the boats had mentioned he had A frames he could include so we'll try and figure out that some more
We're possibly looking for a bigger boat (as we'd hope to venture across the channel and be able to do some canals in the future) so that's good to understand a bit more how tabernacles can work. We've seen a few boat listings with a 'mast lowering system' with a pole but weren't sure how the boats do it. One of the boats had mentioned he had A frames he could include so we'll try and figure out that some more
Refueler
Well-known member
cheers Refueler - I'd often wondered how people do the lowering and what happens with the standing rigging
We're possibly looking for a bigger boat (as we'd hope to venture across the channel and be able to do some canals in the future) so that's good to understand a bit more how tabernacles can work. We've seen a few boat listings with a 'mast lowering system' with a pole but weren't sure how the boats do it. One of the boats had mentioned he had A frames he could include so we'll try and figure out that some more
People will tell you a single pole - Gin pole - is good enough --- please don't ... I tried and it requires careful side control as the 'Gin Pole' wants to swing to side and then mast falls .. its trying to find the shortest line from mast to deck point as the mast to base angle changes ..
The A frame is steady and all you do is look after the mast while letting out line to lower.
My frame is just under 3m high for an 8.5m mast ... as you see in the video.
A frame can be used for a keel stepped mast - but then it needs to be tall.
Marceline
Active member
ah - really appreciated - thanks so much for the extra info and advice
