Double Diagonal Topside Seams

3M 5200 tends to be frowned on by the 'real' wood boat people over the pond, as it is a PU mastic adhesive and cannot be dismantled later. Very good if you don't want it fail.
 
DownWest said:
3M 5200 tends to be frowned on by the 'real' wood boat people over the pond, as it is a PU mastic adhesive and cannot be dismantled later. Very good if you don't want it fail.
Click to expand...

When Replacing planks I was planning on bedding them in a PU adhesive as an alternative to the calico. Do the real wood people have another a different alternative to calico and white lead which can be dismantled but has a longer design life? I'm quite interested to hear people's ideas on a modern alternative to calico.
 
I have done repairs to DD boats, even moderate damage means taking half the side of the boat out, each intersection has 4 or even 5 rivets, one each corner & one in the middle, thats a lot of rivets. You can still get calico or you could i suppose use dacron soaked in the goop of your choice. As said they were not meant to be repaired & were built for a short hard life.
I have done a similar boat a 1905 Saunders launch, built in copper sewn consuta construction she was in very poor condition but was sucessfully replanked, I sandblasted the interior & epoxied it to hold the copper stiching in place. The outer layers were then removed cleaned & three new skins laminated onto the original inner skin. This created a new cold moulded hull with most of the original inside layer. I doubt this would be an economic option on a big boat!
 
Daft idea but here we go ....
Captain tolly creeping crack cure.

Basically a thinned epoxy and it does seem to work. I’ve injected it into various hard to fix places and used it over decks to seep into places I cannot easily get to. Seems to work well and once the crack or movement is sorted, it appears to stay sorted.
 
Whilst I'm a pretty big fan of Cap'n Tolly's I think the quantities involved would make it impractical, I doubt they make enough in a year!

I'd always assumed it was a thinned PVA...

PhillM said:
Daft idea but here we go ....
Captain tolly creeping crack cure.

Basically a thinned epoxy and it does seem to work. I’ve injected it into various hard to fix places and used it over decks to seep into places I cannot easily get to. Seems to work well and once the crack or movement is sorted, it appears to stay sorted.
Click to expand...
 
PotatoNavigator said:
When Replacing planks I was planning on bedding them in a PU adhesive as an alternative to the calico. Do the real wood people have another a different alternative to calico and white lead which can be dismantled but has a longer design life? I'm quite interested to hear people's ideas on a modern alternative to calico.
Click to expand...

Sorry I didn't get back earlier. The Real Wood lot were (are) more talking about using 5200 on conventional wood construction, instead of bedding materials. Quite simply because the next bloke who needs to replace a bit, can't do so because it is glued.
Double Diag is a different world and, with my limited experience on one small project, would be a very labour intensive fix for the whole of the topsides on an ASR
Another thought is 'what was done then, but could be better done now' So, PU mastics (I use Sika 11FC) would have been a load better than calico and goop, if they had had them.
Trying to inject stuff between the layers sounds like a hopeful idea, with no way of checking how well it permiates. Apart from mixing with old materials in the joint, which likely will not stick to it.
Pulling the outer layer and a total refix is the best, if awe inspiring on time.
 
Last edited:
Sticking the planks?. I glued my top side with epoxy when I took it apart due to a five inch bit of rot growing to half the size of the actual side of the boat. Very alarming thinking back!. Wish I hadn't used epoxy too. D/D hulls should move and flex with the sea and Roves and screws allow this more than any thing sticky. I don't think that being able to split the planks again has anything to do with the way they fastened them in the first place. It took me forever to locate release the hundreds of roves and bronze screws and these little copper nails have a lot of holding power for their size . Soaked calico is used to stop any water seeping down the gap between the layers. Sikaflex has no place between the planks either but is best for sealing windows or bedding stanchions IMO. Its a Labour of love and you are probably better off getting rid of it or if it's still sea worthy then just enjoy it. I have had mine now for twelve years and it was rotting then and it's still rotting now. good luck with it.
 
Last edited:
Thanks for the replies.

I've come to the conclusion it's going to be better to get the boat out and do a proper repair rather than experimenting with various bodges.

I never wanted to go down the epoxy route for the reasons above, and it looks like using a PU sealant as a bedding compound, whilst it would allow the flex is going to have the same result of making future repairs very difficult. My current thinking therefore is a traditional style repair, but replacing some of the materials with more modern alternatives. The plan looks something like this:
    1. Remove outer layer of planking
    2. Coat the inner planking with CPES or other epoxy instead of shellac
    3. Layer of fabric and white lead emulsion, PU coated Polyester instead of calico
    4. Seal new outer planking in epoxy to stabilise and increase durability
    5. Refasten outer planking in traditional way

    There are some parts I'm not sure on though, with a modern fabric would it still be best to use white lead for its anti-fungal properties, or would another goo be better/ last longer, roofing tar perhaps? If I was replacing both layers of planking I know it's important to do a section at a time so the hull doesn't move around, but if I'm just replacing the outer layer is it safe to remove it all in one go, or do I still need to replace in sections? Also if anyone has any experience in lifting a boat like this any advice they can give would be greatly appreciated.
 
You might look at the water based époxy coatings. I use Resoltech Re 1010. First coat is 1:1:1 resin/hardner/water. Second coat halve the water, third, just the resin and hardner. Goes on like milk with a toller, then clears and sets. Very easy to see where you have coated and seals extremely well. My little double ender had the three coats 11 yrs ago and is kept under cover. Only just giving her a paint scheme now.

As for 'lifting' I would fancy a marine railway. Except that you might be on it for quite a while.
 
There is a very good book called "The boat repair manual" by George Buchanan, a must get if you don't have it already.
I have used roof underlay from TP as an alternative to canvas. Can it be used to stick btw the planks?, it's rot proof breathable waterproof .
 
DownWest said:
You might look at the water based époxy coatings. I use Resoltech Re 1010. First coat is 1:1:1 resin/hardner/water. Second coat halve the water, third, just the resin and hardner. Goes on like milk with a toller, then clears and sets. Very easy to see where you have coated and seals extremely well. My little double ender had the three coats 11 yrs ago and is kept under cover. Only just giving her a paint scheme now.

As for 'lifting' I would fancy a marine railway. Except that you might be on it for quite a while.
Click to expand...

Traditional boat supplies seem to stock it, quite a bit cheaper than CPES.

I'd prefer getting it out on a slip, unfortunately I don't know of one in the Southampton area that has the associated equipment to get it out and blocked off.

Pells said:
There is a very good book called "The boat repair manual" by George Buchanan, a must get if you don't have it already.
I have used roof underlay from TP as an alternative to canvas. Can it be used to stick btw the planks?, it's rot proof breathable waterproof .
Click to expand...

Tyvek, great idea, I hadn't thought of it. It's also highly chemical resistant so should be OK being exposed to linseed oil. I've ordered a copy of that book, I have half a dozen similar books but none of them go into much detail about double diagonal and none have any suggestions about how it might be improved with modern materials.
 
How about the boat building training school, or whatever it's called, at Portsmouth dockyard? Hugo Andrae took his old family boat there and it came back like new. I imagine you pay for the materials and apprentices do the work.
 
PotatoNavigator said:
Thanks for the replies.

I've come to the conclusion it's going to be better to get the boat out and do a proper repair rather than experimenting with various bodges.

I never wanted to go down the epoxy route for the reasons above, and it looks like using a PU sealant as a bedding compound, whilst it would allow the flex is going to have the same result of making future repairs very difficult. My current thinking therefore is a traditional style repair, but replacing some of the materials with more modern alternatives. The plan looks something like this:
    1. Remove outer layer of planking
    2. Coat the inner planking with CPES or other epoxy instead of shellac
    3. Layer of fabric and white lead emulsion, PU coated Polyester instead of calico
    4. Seal new outer planking in epoxy to stabilise and increase durability
    5. Refasten outer planking in traditional way
    .
Click to expand...


  1. Surely the calico is cotton, and it works because the fibres absorb water and swell up? what would your proposed polyester cloth be bringing to the party?

    I see two options. Upside down, all planks off, complete replanking job with epoxy.

    Or, outer planks off, traditional materials, planks back on.

    On the BMPT forum a few years back was a guy called Magic Fingers, he ran the boatyard that MTB102 trust bought, he did quite a few double diag repairs. He's be good to seek advice from.
 
burgundyben said:
Surely the calico is cotton, and it works because the fibres absorb water and swell up? what would your proposed polyester cloth be bringing to the party?

I see two options. Upside down, all planks off, complete replanking job with epoxy.

Or, outer planks off, traditional materials, planks back on.

On the BMPT forum a few years back was a guy called Magic Fingers, he ran the boatyard that MTB102 trust bought, he did quite a few double diag repairs. He's be good to seek advice from.
Click to expand...

I wondered the exact same thing but Calico soacked in boiled linseed oil would already be swollen and full? And why is the oil boiled?
 
Pells said:
I wondered the exact same thing but Calico soacked in boiled linseed oil would already be swollen and full? And why is the oil boiled?
Click to expand...

BOILED LINSEED OIL. Boiled Linseed Oil is used to give a mellow, patinated finish to new or stripped bare interior wood. It is a superior quality oil, similar to Raw Linseed, but has had hot air passed through it to improve drying times.
 
burgundyben said:
Surely the calico is cotton, and it works because the fibres absorb water and swell up? what would your proposed polyester cloth be bringing to the party?
.
Click to expand...

Cotton in white Lead has a very short life span. Considering the amount of cost and effort involved, I'm trying to come up with something that won't have rotted away in 10 years leaving me in the same position. I'm fairly convinced the synthetic fabric will work OK, the only thing I'm left wondering is if there will still be benefit to 'soaking' it in white lead or if there might be a better bedding material, tar of some sort perhaps.

Pells said:
I wondered the exact same thing but Calico soacked in boiled linseed oil would already be swollen and full? And why is the oil boiled?
Click to expand...

I thought raw was preferred to keep it from drying as long as possible?
 
burgundyben said:
I came back to this thread to post because I recalled SpudNav wanting to put the boat on a slipway rather than lift (very commendable), so I scanned through the pages but can't see that now...anyway...

I stumbled across this http://woodenshiprepairs.co.uk/index.php/news/ its in Cowes and I live in Cowes but didn't know!
Click to expand...

I think it might be a bit pricey to stay on their slip whilst I replace the topsides! Useful to know about though for smaller jobs in the future, thanks.

Did you see my previous reply about the synthetic fabric? I'm thinking if I used something like tyvek, it won't need to swell in order to seal since it is inherently waterproof, so the inner planking should be protected long term. I have a concern about the longevity of the white lead emulsion between the fabric and the outer layer, since the fabric won't swell it might lead to water being trapped behind the outer planking. I'm not sure if this could happen, but assuming it could, would tar be a better for bedding than white lead, or is there no risk of the white lead being 'washed away' if the fabric cannot rot?
 
You must log in or register to reply here.

Share this page

Top