Hull Deck Joint

Clyde_Wanderer

Clyde_Wanderer

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I have removed the old wood port side rubbing strake today for renewal.
The old strake was through bolted with 91 bolts leaving boat like a collender,(see pic) the bolts were in two rows (up and down) and went through the strake, deck and hull, the deck/hull joint is also glassed on the inside done before the bolts were fitted TG.
Bolts were aprox every 3-4" apart?
I intent to fit a straight row of bolts somewhere around 10-12" apart through the deck/hull directly, then fix the new strake with self tappers and plugs.

Was 91 bolts overkill?
Does my method of refixing sound ok?
Appreciate advice.
C_W
P1040400.jpg
 
Clyde_Wanderer said:
Was 91 bolts overkill?
Does my method of refixing sound ok?
Appreciate advice.
Click to expand...
I'm curious to know why you don't intend to refix using the same bolt holes ? As you say the existing holes go completely through the gunnels there should be no problem with access, or have I misunderstood ?

Boo2
 
Boo2 said:
I'm curious to know why you don't intend to refix using the same bolt holes ? As you say the existing holes go completely through the gunnels there should be no problem with access, or have I misunderstood ?

Boo2
Click to expand...

Would have to be drilled from inside . lack of access ?? Just a thought .
 
It does seem like overkill for something that is not part of the structure or required for strength. I wouldn't be keen on drilling new holes and fitting new self tappers if there are already another 91 holes there. Is it just to save some time? If so could you fit a new rubbing strake using existing holes but use only every 4th upper and lower holes?
I like the new decal of the hummingbird. You beat me to it I was looking to do one with a shearwater. Is that an old pic cos I don't see any mast yet?
 
91 bolts may be a bit over the top, but self tappers wont be up to it.
Rubbing strakes as the name suggests must be able to take a bit of abuse.

I can understand why you don't use the existing holes, as drilling from the inside would be difficult. However I would suggest a line of 6mm machine screws at 10 or 12 inch centres through the strake and hull/deck joint, bedded on sicaflex and the screws plunged.

Scarf any joints in the new strake before you fit it as its very difficult to do so in situ

Plank
 
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Remember the yacht's hull will distort when sailing to some extent and the deck / hull edge could be trying to hinge, so the stresses may be somewhat higher than you think and you will just concentrate a higher stress over the bolts. The GRP over the 10 to 12" you are proposing may become stresses too much. I would be inclined to refit as installed by the builder especially is you have never had any trouble with leaks from the hull.
 
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Oh well, just to be different.
Drilling from the inside offers no guarantee of a neat zigzag of finished plugs in the new strake.
I would therefore countersink( cleans as it keys as it prepares) all existing hold and fill from outside with epoxy/colloidal silica mix then Dremel all flush to surface once cured...
And fit new one piece strake on sikaflex using bolts if you can access the rear easily. The sika will do most of the bonding but the bolts will prevent shearing if you ride down hard onto someone else's rubbing strake or jetty edge. Therefore arguable only one row of fasteners is required but often a zigzag will help prevent twist as you wrap the new strake around.
I take it all this is because of the winter yard damage, good luck.
 
Er, what's the method of fastening the deck moulding to the hull moulding? Are you sure it wasn't all those bolts holding it all together with the rubbing strake as a capping to finish it off neatly?

This month's PBO has some good pics of how it is sometimes done and that looks suspiciously like a hull-deck joint....... :eek:

I hope I'm completely wrong on this one, but its difficult to see from a single photo....
 
bignick said:
Er, what's the method of fastening the deck moulding to the hull moulding? Are you sure it wasn't all those bolts holding it all together with the rubbing strake as a capping to finish it off neatly?

This month's PBO has some good pics of how it is sometimes done and that looks suspiciously like a hull-deck joint....... :eek:

I hope I'm completely wrong on this one, but its difficult to see from a single photo....
Click to expand...

Thats how we used to do it ;)
 
Eamonn, I would put it back the way it was if it's at all possible.
What's your insurer going to say if it comes loose in a blow? (assuming you're around to claim...)
There's shroudplate stress to consider as well as general flexing.
 
Thanks for the replies, although there seems to be some mis interpretation of my post.
Yes it is the hull/deck joint.
Yes the hull/deck joint has been lightly glassed on the inside of boat.
Yes there was water leaking in at the joint along the original bolts.
The boat was not builder completed it was a home completion.
Why would I have to drill through from inside?

As I said in original post, the 91 6mm bolts went right through the strake, deck overlap and hull joint, and had nuts and washers on the inside.
The problem with this set up was that the bolts were never tight enough as the wood swelled and shrank with weather, resulting in loose bolts and water ingress.
I was going to use one straight row of 6mm button head bolts aprox about 8" spacing with special sealing washers on the outside and nuts and washers on the inside, inside access mostly easy.
The reason for this is that the bolts would only be through the deck hull joint, permenantly sealed and permenantly tight, which in my opinion would be far stronger than 90 loose bolts.
I was then going to router out a small channel on the rear side of the strake to clear the bolt heads, then fit the strake with No12 self tappers which would be recessed into strake by 1/4" and covered with plugs glued in.
All in all the deck to hull joint would be pulled tight permenantly, and watertight, the strake would be bedded with sikaflex and there wouldent be much chance of the screws being damaged as they would be well recessed into the strake.
I do intend filling the old bolt holes with cataloy, as they will also be covered with sikaflex while bedding the new strake.
Spyro, that is a Kingfisher, not a hummingbird, there is a storey to it!;)
Mast not ready yet!
C_W
 
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On my Westerly Fulmar the rubbing strake is through fastened with 5mm bolts and then the nuts are glassed over.In theory it's not a good method because of the movement of the wood but in practice it works very well.There are absolutely no leaks because of the glassing and the rubbing strake shows no signs of movement after over 30 years.
 
Clyde_Wanderer said:
As I said in original post, the 91 6mm bolts went right through the strake, deck overlap and hull joint, and had nuts and washers on the inside.
The problem with this set up was that the bolts were never tight enough as the wood swelled and shrank with weather, resulting in loose bolts and water ingress.
I was going to use one straight row of 6mm button head bolts aprox about 8" spacing with special sealing washers on the outside and nuts and washers on the inside, inside access mostly easy.
The reason for this is that the bolts would only be through the deck hull joint, permenantly sealed and permenantly tight, which in my opinion would be far stronger than 90 loose bolts.
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I'd use the original scheme just on the basis that the designer would've known what it took to keep the deck and hull bolted together. If you're worried about the bolts loosening in the way you suggest then you could fit thick-wall tubing into the holes through the strake and bolt down onto that instead of the wood directly. Or just clearance drill the strake all the way through and attach it seperately. Lots of Sika or Butyl rubber sealant in the holes should see you right.

Boo2
 
Clyde_Wanderer said:
Would that not be the same as my intended method of through bolting the hull/deck joint first then fitting the strake independantly
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Yes, but I'd use the original holes rather than make new ones to a sparser pattern as I understood you were intending.

Alternatively, to keep the strake from compressing and loosening the bolts you could use stainless spacers like these which are available in various lengths. Choose a length around 1/16" shorter than the strake is thick and insert into holes drilled to fit the O/D. When you bolt up the head should tighten up to the spacer so what the wood does afterwards is less of an issue. Just an idea,


Boo2
 
91 bolts is a fair number - but the strength of grp is not high - particularly when subjected to point loads - hence the number of bolts. The best analogy would be aluminium boats or aircraft - where the weak point is the thin aluminium sheets and to keep the 'point' loads down hundreds of rivets are required.

So I would reuse the original holes - separately attaching the rubbing strake - where something like Sikaflex would almost hold it on regardless.
 
Pete54 said:
91 bolts is a fair number - but the strength of grp is not high - particularly when subjected to point loads - hence the number of bolts. The best analogy would be aluminium boats or aircraft - where the weak point is the thin aluminium sheets and to keep the 'point' loads down hundreds of rivets are required.

So I would reuse the original holes - separately attaching the rubbing strake - where something like Sikaflex would almost hold it on regardless.
Click to expand...

Good advice and a very good analogy.
 
Pete54 said:
91 bolts is a fair number - but the strength of grp is not high - particularly when subjected to point loads - hence the number of bolts. The best analogy would be aluminium boats or aircraft - where the weak point is the thin aluminium sheets and to keep the 'point' loads down hundreds of rivets are required.

So I would reuse the original holes - separately attaching the rubbing strake - where something like Sikaflex would almost hold it on regardless.
Click to expand...

Agree with most of the above apart from the last line. When replacing my rubbing strake I found the curve towards the bow to be quite considerable when one is trying to bend a nice piece of teak rubbing strake to suit. I was glad to have several bolts to keep the strake in position.
 
Pete54 said:
91 bolts is a fair number - but the strength of grp is not high - particularly when subjected to point loads - hence the number of bolts. The best analogy would be aluminium boats or aircraft - where the weak point is the thin aluminium sheets and to keep the 'point' loads down hundreds of rivets are required.

So I would reuse the original holes - separately attaching the rubbing strake - where something like Sikaflex would almost hold it on regardless.
Click to expand...

I take your point, but I dont think sika would hold on the strake as it is aprox 28mm thick by aprox 70mm wide Iroko.
Thanks.
C_W
 
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