Work on Planet, N12 N672 1948

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Michael4
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Re: Work on Planet, N12 N672 1948

Post by Michael4 » Tue Nov 24, 2015 10:06 am

Steve,

Many thanks, it is certainly worth a try on some of them. Written by Jack Chippendale? I love the tale of him doing fine until he got an accountant and then going bust!...

Michael
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Michael4
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Re: Work on Planet, N12 N672 1948

Post by Michael4 » Tue Nov 24, 2015 12:44 pm

Steve (and all),

While sitting in this morning's A27 jam I thought more about this issue of the cracked planks.

It boils down to the question of how much a 'dry sailed' clinker boat actually takes up. A discussion that has been aired before I think.

From experience the Tideway leaks far less at the end of the year than it does at the beginning but it is used a couple of times a week and has been known to spend nights on a mooring or the mud. ie it is more often than not damp, regularly wet and does take up.

I would guess that the N12 will get used less and consequently drier.

However when I first mentioned using epoxy and fillets etc in the cracks Chris expressed caution because where would the additional width go when the planks swelled even a bit?

The idea of making it take up moisture first then finishing it has its problems too. Once it is that damp paints and sealants will have a tough job adhering properly to it.

The answer may lie in finding a sealant that remains flexible long term and will squeeze out as they swell.

Plenty of time to ponder and all suggestions welcome, won't get back to working on Planet till spring.



Michael
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Stephen Hawkins
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Re: Work on Planet, N12 N672 1948

Post by Stephen Hawkins » Tue Nov 24, 2015 4:46 pm

No mate, Ian Proctor was the designer. Mr Chippendale was the builder. Your Merlin is a Proctor MkVIII.

However, he does also mention also, on page 16(I think) about not filling in the cracks, etc. Although he does specify some repair techniques. Tingles rings a bell, whatever tingles are : )

I will try and get it to you in a week or so, Its my bed time reading.....

Cheers

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Michael4
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Re: Work on Planet, N12 N672 1948

Post by Michael4 » Tue Nov 24, 2015 6:28 pm

I should have read your email properly, I have stared at Mr Chippendale's nameplate, even under water...

BTW, did you see that N12 Proctor MKVIII, spitting image of the Merlin. (Can't find the link)

Traditionally (from what I remember) a tingle is is a copper patch shaped to fit, covered with lead putty and tacked onto the outside of the boat. I have used them on an old big boat to some effect using whatever I could find at the time, ie a bit of lead flashing and some nasty goo. They are very effective but perhaps inappropriate in this instance!

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realnutter
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Re: Work on Planet, N12 N672 1948

Post by realnutter » Tue Nov 24, 2015 10:42 pm

My wooden narrowboat owning friends would say oakum at this point...

But they've got 2 or 3 inch thick planks to seal between... :lol:
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Re: Work on Planet, N12 N672 1948

Post by Stephen Hawkins » Wed Nov 25, 2015 8:27 am

I think in this case the tingle was inside the boat and made of wood. Either way, a temporary repair.

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Re: Work on Planet, N12 N672 1948

Post by Michael Brigg » Thu Nov 26, 2015 6:32 pm

The boat has what is fashionably known as a 'soggy bottom'. The starboard side flexes quite easily when pressed with the heel of the hand but that is hardly surprising. It is also slightly out of shape around one of the garboard joins but I doubt there is much I can do about that. The cracked planks have little lateral strength but seem OK fore and aft.
The only real answer here is getting her wet.

OK Planet has been drier than Mercury for however long, but nevertheless, the wood ultimately has to be allowed to re-expand and sooner rather than later. I have read somewhere I think that the horizontal expansion can be as much as 6 times the amount that you get in longtitudinal expantion. So, as the strakes expand this will tighten the fastenings and particularly the ribs will tighten up.

Some would even advocate sinking her on a tidal salt mudflat for a month. (Along the lines of exposure on the mountainside will make your children strong!) The salt will act as a preservative (a bit like Cuprinol.) Speaking of which, actually if you have her stripped off, you could prevent, or at least postpone, future rot by giving the dry wood a good drink with Cuprinol CLEAR. It works under varnish on wooden window frames, and is just as good for boats too!) It would help expand the wood too.

If you are more cautious, just do a daily light spray with water (or clear cuprinol) with a wall paper brush or a hand held humidifier spray. Best to use a salty fluid though as fresh water may promote rot.

As the tightening structure expands you will find it gets to a "locking" point where everything is tight, and at that point the only way to expand any more is by closing the cracks.

The reabsorbed water is incorporated into the matrix of the wood, a bit like water of crystalisation, and so when the hull "dries" it still contains the water, but will be dry enough to accept the varnish that follows. Those longtitudinal cracks, (so called shakes) however scary they look are really no different to the gaps between the planking, and will close in the same way, and are not of any structural consequence, as they will be held together by the collective strength of all those copper fastenings and all the ribs.

The Clinker construction technique in its day was the equivalent of Carbon fibre as a way of improving the weight : strength ratio. A carvel built boat of similar size would need to be 3 times the weight for the same stiffness. Clinker boats should be admired as the marvel of clever design that they are.
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Re: Work on Planet, N12 N672 1948

Post by neil » Thu Nov 26, 2015 9:06 pm

I'm with Michael on this. Find a nice muddy berth and let the boat take up. Leave for a while, pump it out and let it settle, repeat until the boat floats. All that is required is patience.

For a slower take up, wet hessian on the inside will help it take up. The old salts I used to work with would also recommend launching in a stew of sawdust, the theory being that it also gets taken up. There's been a few of us launching into the mud at Roadford then pumping out as required. If/when Zenith sees the water I know the 1/8" gaps will take up after a while. Just need to be patient and bail if required.

Just don't do what a the previous owner of my old Tideway did - take a hosepipe and fill the boat with water. Turned a £3k Tideway into a £500 project in an hour as the boat was on a trailer, not tied down, the boat went stern down and broke its back and a load of ribs.

Tingles are a last resort, a plaster until you can repair, caulk or replace.
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Re: Work on Planet, N12 N672 1948

Post by roger » Thu Nov 26, 2015 9:18 pm

My dad always used to put his clinker Lymington pram out on the trot line in the mud with the bungs out for a week. Bungs out so that water getting in when she was floating could get back out again when the tide went out.
She took up nicely and hardly needed baling out all summer apart from rainwater.
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Re: Work on Planet, N12 N672 1948

Post by chris » Fri Nov 27, 2015 10:21 am

On some woods the expansion is about 1/16" for every inch width across the grain so a 4" plank it could be as much as 1/4" from one extreme to the other. So if any gaps are less than that I really would suggest getting it wet before you do any filling. Otherwise it could result in more problems.
On my 14 which is carvel not clinker there were many gaps upto 2mm wide. Some of these had been filled with a hard putty type of stuff. I picked all this out. Since the layers of the skin are only about 3mm thick I simply painted it with water several times and that made quite a difference. Then I varnished and then sailed the boat. at first it leaked badly but then closed up very nearly completely. But at the end of the first season it had squeezed out a lot of (plyable) varnish from the joints and gave the hull a very spikey hedghog finish. ( a very good reason for not using epoxy but a traditional varnish.) after a rub down and a couple more coats of varnish I only had to use sikaflex in a few places and now the hull is pretty well sealed. (about an ich of water after a day's sailing.) of course it is a heavier hull when wet!

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Re: Work on Planet, N12 N672 1948

Post by Michael4 » Fri Nov 27, 2015 12:47 pm

Thanks everyone, I'll take you advice and get the boat wet for a few weeks before doing anything with the cracks and if they do need filling I'll make sure it is something soft.

I like the idea of using clear Cuprinol as part of the process. Will it swell the wood as much as salt water? If I use a 'mist' of Cuprinol daily I assume it will repel water if I switched from one to another?

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Re: Work on Planet, N12 N672 1948

Post by Michael Brigg » Fri Nov 27, 2015 4:05 pm

Not a problem because it is a water base. (NB Do not confuse this with Creosote)

Cuprinol Clear is used to preserve fence posts and trellis work, as well as wooden window frames. These have to stand up to alot more sun and frost than the average dinghy.

IT does also come in Green and brown, but the clear stuff goes on and is undetectable under varnish. (Try a tester peice first for peace of mind.) It gives resistance to rot. 1 or 2 coats will suffice. It swells the wood just like water (or sea water.) The more you use, the more it will swell. Like blotting paper.

To be honest a slight softening of the wood surface when damp improves the seal as the edges will "mold" together.

Avoid the mud though as hard residues in the cracks will hold them open.
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Re: Work on Planet, N12 N672 1948

Post by Michael4 » Sat Nov 28, 2015 5:26 pm

Thanks, I hadn't realised that Cuprinol was water based. Will let you know how I get on.
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Re: Work on Planet, N12 N672 1948

Post by ent228 » Sat Nov 28, 2015 9:54 pm

RD Culler in Skiffs and Schooners had the same issue of shrinking planks:

His skiff bottoms were pine and treated with linseed oil and turps mixed and put on hot.(soaks into the wood better if nearly boiling)

When he'd had a load of coats on he recommended lining the inside of the boat with Sacking and taking the bungs out and using a hose pipe to keep it all wet.

Some woods take up (expand) suddenly, particularly if the day is warm and so having the bungs out is really important to avoid the Tideway issue mentioned above.

He recounts many problems with swelling planks afloat as the wood closes up on all sorts of grot and in time the grot wears the planks away as they work and you end up needing new planks after a few years.

The best place to put the boat maybe a nice clean swimming pool for a few weeks and see what happens......:)

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Re: Work on Planet, N12 N672 1948

Post by Michael Brigg » Mon Nov 30, 2015 2:14 pm

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