Bedding compound on wooden deck

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yorkie_chris

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Hi chaps,

I am chopping all the timber stanchions off my boat and replacing the covering board.

The new covering board is laminated larch, the nibbed plank next to it works like oak and I think the rest of the deck is keruing.


My new stanchions are welded up out of 8mm 5083 ally. They're going to be screwed down with 316 screws.

What should I use to bed them down on the deck with for minimal leaks and rot points?

Cheers
 
I would favour either polysulphide (Evo-Stick Polysulphide as available from Jewsons etc. or Arbokol 1000) or butyl rubber (Arbomast BR). I have used both, either sticks well and remains flexible which is important for stanchions on a wooden boat. Unlike Sikaflex, they allow for removal of fittings in the future. The polysulphides come in a range of colours while the Arbomast is usually grey.
 
A word of caution - it’s best to secure stanchions onto pads (teak or iroko etc) which are a good half inch thick and a good half inch to an inch bigger than the stanchion bases. This is standard good boatbuilding practice and greatly reduces the inevitable leaks. As regards sealant, give all the timber surfaces a couple of coats of primer and let it dry well before applying the mastic. This stops the solvent in the mastic leaching into the wood and leaving the mastic dry and crumbling..
 
tillergirl said:
A second word of caution - 'Screws'! I regard screws for stanchions as very dangerous. Not suitable for that purpose. But that's my opinion.
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Don't think the stanchions here are for guard rails but for the covering boards. Perhaps the OP could clarify.
 
I agree it isn't clear but even for use for the bulwarks I wouldn't use screws. Screws are great at resisting a direct pull but a stanchion will inherently put pressure on the side. I think it is a good idea to avoid the timber stanchions through the deck; keeping the deck watertight is then a nightmare. On TG the chainplates were originally through the covering board and fastened on the inside of the planks and the then 1985 surveyor recommended they were external as they were constantly working at the covering board. Since then there has been no trouble. And bolting through 'yacht style' stanchions can be achieved without causing deck leaks.
 
They'll be held down with stainless lag bolts, me and the surveyor (actually a marine engineer not a yacht-poker) did the stresses on them, it will be adequate.
I see what you're saying and don't disagree but it would not be possible to do the nuts up on the inside of the covering board further aft, there is too much timber work in the way.

These stanchions are for timber bulwarks not for wires or ropes.

Can't get a pic to upload to show you
 
aka to me - coachbolts. I had to use coachbolts on the outer fastenings for the pushpit and pulpit as the hull shape made bolts impossible. I was thinking originally you were using screws.

Good oh.

Images are possible if you have a hosting site. Or email it to me via my web site and I'll host it to the thread for you.
 
Minn said:
Yes, I am assuming for bulwarks.

I replaced my oak bulwark stanchions with teak through a teak covering board and did it that way, but the OP’s method is better, I think.
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Teak through teak would be really good but I would have to sell a kidney and take up international arms smuggling or something as well. The original stanchions are 6" square approx and the covering board is 9"x 2 1/2" thick and I have about 40' each side to replace. Would be a few quid in that lot to do it in teak.
 
No worries. I suspect I would have a timber 'pad', under the stanchions, bedded on polysulphide. Not sure it needs the pads but I would have done.

Nice bit of welding (I zoomed in).
 
On my knees on deck today, I reminded I should have said I needed the pads because I had standard vertical bases and so needed shaped pads adjusted to cope for the 'tilt' of the deck.
 
These are just getting bedded straight down with polysulphide - no pad. Partly because I'd already spent a few hundred quid on 316 coach screws to hold them down and they would have been to short with an extra pad in there.

Did the first one today, the sealant takes enough slack up and the radius of the shearline is large enough that a flat base is fine.

Regarding the angle, just to make life more fun, all of these stanchions will be at different angles, so they are at the same angle as the originals. I think it would have looked weird if they were all perpendicular to the deck
 
My only concern is screwing down onto both the decking and the covering board and whether there is likely to be movement between the two. Assume they both sit on the beam shelf so hopefully both are stable.
 
It's a thought. They're secured together with a 16mm steel pin driven in 20" from the outside.
Not secured to the deck beams as they stop at the beam shelf, not all the way to the shear plank.

Doubt they'll move far. Have had a lot of problems with the deck shrinking in the heat this past few month and the joint between covering board and first deck plank (nibbed plank? Not sure what you call it) is the only one that hasn't opened up.

The rest have all opened up 1mm or so, the problem with taking a deck that's been wet and covered in fish for 50 year and letting it dry out. :(
 
yorkie_chris said:
These are just getting bedded straight down with polysulphide - no pad. Partly because I'd already spent a few hundred quid on 316 coach screws to hold them down and they would have been to short with an extra pad in there.

Did the first one today, the sealant takes enough slack up and the radius of the shearline is large enough that a flat base is fine.

Regarding the angle, just to make life more fun, all of these stanchions will be at different angles, so they are at the same angle as the originals. I think it would have looked weird if they were all perpendicular to the deck
Click to expand...

My pads were only there to sort the angle on the deck right. Fortunately I was able to re-use the original iroko pads. More photos?
 
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