Timber masts

ianc1200

ianc1200

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Is it possible/sensible to split a timber mast & glue back together again?

Last winter I bought a Mk1 1978 Cornish Crabber, and the only point on the survey requiring immediate attention was the glued joints in the mast were opening up - this was in several places, with the worst area at the base & about 2-3mm.

I poured thickened epoxy in & quickly realised it was all going down into the void for the wires for mast head lights and the VHF cable. Eventually it was glued to my satisfaction, and after a panic when I thought it was glued too wide to fit into the tabernacle (it was OK) the mast was varnished & put up for the season.

However I then found the VHF aerial wasn't functioning but the mast head lights, despite the cable being very old, was OK.

I now have the mast down, all lights etc off, and there's obvious movement of the cables at the top of the mast, but none at the base.

It has been suggested I have a groove routed in the mast & re cable that way, but I just wonder whether I could go to an expert & ask him to spilt the mast, re-wire & glue up to the original width. As the mast is 35 years old, this would also give me reassurance about it's condition.

I don't even know what sort of "expert" I'm looking for (general shipwright - or a specialist mast/spar company like Collars?).
 
The SCOD I bought and restored had a wooden mast with a glue joint that was failing in multiple places. I stripped it right down and carefuly cut down the glue joint, cleaned up the surfaces and glued it back together. My surveyor (and the boat yard where I was working) advised me NOT to use epoxy but Cascophen as it's less brittle and less subject to UV damage.

Lots of wood bleach and sanding and many coats of varnish and the mast was a thing of beauty once more. It also won us some silverware at Cowes so it couldn't have been too bad a job.

PS At the risk of stating the obvious, you need to own or borrow a LOT of clamps!
 
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I'd be going to a company like Collars. A shipwright would certainly give you his opinion but he's unlikely to have anything near the relevant experience that a specialist spar maker will have.

Personally, if rewiring is the only real issue I'd just lead some new cables down the shrouds. I certainly wouldn't go routing a groove for the cables since that can only result in a loss of strength.
 
I've definitely heard of masts with failing glue joints being split and reassembled, but god knows what sort of a job it would be after you've filled the internal channel with epoxy :(. Bigger masts do sometimes have a slot routed for cables, but my gut feeling is that a Crabber mast might be a bit small to lose the material and retain sufficient strength. Maybe it would be ok, but you'd be forever wondering... Unfortunately the size of slot you need doesn't doesn't really vary with the mast size, so a tiny sliver up the tree-trunk on a fifty-foot pilot cutter translates to a big chunk out of a twenty-footer's more delicate pole.

Pete
 
A friend has a boatyard and they maintain a lot of wooden boats, almost every winter they have a mast or two to repair, the last one I watched him doing he just got a hand saw and cut along all the glue joints and in half an hour he had a "kit" mast (about 30 feet long). I cant remember what glue he used but it was wood glue NOT epoxy.
If you do have to cut it open you can then install some conduit for the cables.
good luck.
 
saltylegs said:
If you do have to cut it open you can then install some conduit for the cables.
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The Collars masts used on Crabbers already have a channel up the inside. I haven't seen one open, but I assume they just run a router up the centre of each flat surface before gluing them together. It's not a particularly wide channel, I had a bit of a struggle to pull out two lengths of 2-core (nav lights) and one three-core (NASA navtex antenna needlessly mounted at the masthead) so I assume those three relatively thin cables more or less filled it.

Not at all clear what additional benefit inserting conduit into the channel would bring.

Pete
 
Stops cables rattling around if the hollow is quite large and lessens the chance of damage by chaffing to the cables if there are any screws etc. protruding into the hollow.
I have 2 hollow masts that I made myself although no cables in them the small one has an internal hollow of about 20mm the other which is 22 feet long has an internal diameter of about 50mm so plenty of room if needed.
 
saltylegs said:
the other which is 22 feet long has an internal diameter of about 50mm so plenty of room if needed.
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Certainly a conduit in there makes sense, but I believe based on the weight that the mast on our Crabber was solid (apart from the narrow routed channel).

Pete
 
The mast certainly appears to be solid with two halves glued together with a groove. As it's about just under 30' long is it easy to get transported to somebody if I can find local (Walton on the Naze).
 
Jamie Byam-Shaw at Heybridge Basin. Has a workshop in CRS Marine next to the Tiptree Jams cafe (outside the lock). He does spars and oars and tillers and things. Very skilled. I am assuming he is still there.
 
I have a Norfolk Smuggler with a Collars mast and have a similar problem. My mast is made up of about 6 sections and there are a couple of areas where the glue has failed and the sections are separating. I have been advised by a shipwright to use a West Epoxy resin with a slow hardener (206 I think). I plan to lower the mast and the scrape out and roughen the joints with a hacksaw blade and then inject the resin with a syringe. Others recommend Cascophen/Cascomite. So I am not sure which is best adhesive. I note that Cascomite needs to be clamped whereas this is not the case for epoxy. For me the gap filling properties of the adhesive will be a factor. I have contacted Collars and asked for their advice and await their response. I have PMd you and suggest we keep in touch and compare notes. I will also post updates on my experience here. If any forumites with wooden masts have any further input it would be most welcome .
As for passing the wires, I see no need for a conduit. The masts are made with a recess for passing wires and noise is not a problem. As for splitting the mast. I am sure it is possible but I wouldn't do it unless the joints were in bad shape.
 
There is - or was - a spar manufacturer on the quay at Maldon, I can't remember the name I'm afraid, but he made me a beautiful spruce spinnaker pole for my RHOD some years ago.
 
ianc1200 said:
Is it possible/sensible to split a timber mast & glue back together again?
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Amulet's mast was built hollow in four parts as shown in the diagram below. Originally glued and clamped with Aerolite by my father in 1963 ish. Aerolite was claimed to be waterproof, but turned out not to be on a 40 year time scale. Kings of Pin Mill dismantled and reassembled the mast gluing it with epoxy. The method was to remove one quarter allowing the other three to maintain the integrity of the structure and then clean it up and glue it back. The opposite quarter was then removed and the process repeated. It is doing fine twelve years on. So yes, it can be done.
 
ianc1200 said:
The mast certainly appears to be solid with two halves glued together with a groove. As it's about just under 30' long is it easy to get transported to somebody if I can find local (Walton on the Naze).
Click to expand...

Yep, that looks just like Kindred Spirit's mast - except, if I may say so, a bit shabbier :). I hope there's usually a truck on top protecting that end-grain?

Pete
 
Thanks for all the suggestions & PM's, thought I'd add this filmed by Steve (Sophie19) of mast raising & lowering. Four new owners of Mk1's meet to have a go at the Dutch way of doing this (my boat came from Holland with this gear, really a scaffold pole).

http://www.youtube.com/watch?v=P1HMWMId3UQ

The truck had been taken off to free the wiring up, and the base of the mast does look shabby!

Pete, as a former owner, did you have much problem in getting the mast down? We found the base of the mast binding on the tabernacle such that it required a lot of effort to start it moving. It seems the Crabber masts are designed with only one bolt (to pivot on) with the base of the mast designed to sit on the tabernacle & transmit the thrust. My other boat has two tabernacles with the base of the mast a couple of inches above the tabernacle bottom plate.
 
Last months PBO had a 'how to' on wooden masts, both hollow and solid for a guide on construction. They glued theirs up with Resorcinol.
 
LP1 said:
Last months PBO had a 'how to' on wooden masts, both hollow and solid for a guide on construction. They glued theirs up with Resorcinol.
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Resorcinol requires a clean wood surface, while epoxy will stick to other glues. And, be very careful about temperature with resorcinol, an overnight dip below 10deg can stop it working.
In this case, I would consider running the spar through a bandsaw on the joint, cleaning up the faces and regluing with epoxy ( the wiring would be cut out in the process). But routing out a groove for a PVC conduit. This allows one to glue the mast up without worrying about squeeze out in the cavity. Epoxy comes in many flavours, some (system 3) are more flexible than others.

A good fix would be to set a circular saw with a thin blade to a set depth and run down the joint, refilling with thickened epoxy after painting the gap with neat (done this on a 50ft). The depth can be clear of the wiring, bearing in mind that the middle bit of the mast does not add much to the strength. Axminster sell TCT blades with 1.6mm kerfs.
 
ianc1200 said:
Pete, as a former owner, did you have much problem in getting the mast down? We found the base of the mast binding on the tabernacle such that it required a lot of effort to start it moving.
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No problem getting it down - it did require a bit of a nudge to start it moving, but I prefer this rather than it trying to fall as soon as you release the forestay.

However, when you come to put it up you will have a similar problem in reverse, and this is more significant. Our first year we just couldn't get the mast properly vertical, pulling harder on the forestay was trying to lift the tabernacle from the deck rather than moving the mast within it. We spent that first season with about 18" of rake instead of the proper 6". The solution, which we used each subsequent year, is to smear a good dollop of tallow all over the bottom face of the mast (I assume you have a tub on board for the gaff jaws, and any other leatherwork such as inside the gammon iron). The mast then slides easily into place. This step is absolutely vital.

Pete
 
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