Grp skinned clinker boat: Advice appreciated.

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SeaDancer

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Hi everybody.

Just registered with the website, please forgive me for not filling my profile in, promises, it will be done!

Having had a small outboard powered boat for several years, mainly used for sea fishing I have now progressed onto a 26 ft clinker built boat with a fairly chunky Lister SL3 engine.

The hull appears to be in good condition with no soft spots but it has been completely covered with a fairly hefty coat of grp.

Any advice would be gratefully received regarding the preservation of the existing clinker timbers. At present, the boat is open from amidships to the stern and collects rainwater, although this may not be so in later years as we are well adept at making canopies etc.

We have had various suggestions ie. salting the bilges, pouring in linseed oil, soaking in old engine oil etc.

Anyway, please let us know what is the best way to keep our timbers rot free.

Many thanks to any forumites who may impart any valuable knowledge.

Best wishes.

Gordon.
 
Stored in or out of water? All year or part of year?
GRP on outside but not in the bilges?
Pump on auto in the bilges?
 
Cover it up to keep fresh water out. Difficult enough to protect timbers in a clinker boat from damp, but probably even more difficult if it is GRP sheathed as the timber cannot breath or move to respond to changes in temperature and humidity.
 
I'll bet there's loads of voids between the planking and the grp skin where water will lie and cause rot.

If it were my boat, and worth the trouble, I'd remove the grp sheathing, deal with any rotten timber, refasten as required, then paint it.

An overall cover is a very good idea. Rainwater is very damaging.
 
In the meantime, whilst you are making your mind up, keep dousing her with buckets of seawater. I do this several times a week with my MAB. AWB owners busy with their pressure washers must think I am GaGa.
 
This may or not be of use to you
I sheathed a Stella 16 years ago & in spite of doubters it is still perfect & does not leak a single drop of water other than via the stern gland.
the boat was a wreck & I mounted it in a cradle then I stripped it to just a hull & some deck beams to keep the shape.
I had the entire hull inside & outside sandblasted. This removed all the paint & some areas of rotten wood
i then applied the West system of bonding the lands.
During this time I dried the hull as much as possible & I think it ended up at about 12% MC
This is important so that any epoxy filler would bond & soak into the lands & having shrunk the wood the joints were as open as they would ever be. Most of the copper roves had failed so I ignored them
I then obtained a resin from Wessex. Forget the name but the fumes are very toxic & although I had an air ventilated mask I did fall ill on one occasion, so it needs application with care. This resin has a seeking property rather like antifreeze & has the liquidity of cuprinol. It forms a crystalline like surface that is very hard & I only needed to paint over it in exposed areas of the cabin & cockpit
I then coated the outside with epoxy & 300grm woven matt
Now how does this help you.?
Well first, if the GRP is not epoxy then get rid of it. Then you need to get the wood really dry - I used fans to push air around & the boat was in a shed
Then you need to get every drop of paint off the boat. My boat had ribs every 9 inches so for me sand blasting saved weeks of work.
Then get the resin from Wessex & coat 3 layers inside the hull
Because you will not get the wood as dry as I did you should not coat the outside again
get a 4 inch angle grinder with a carving blade . The blade needs to be about 6mm th. Then run this along every land deep enough for the filler but not too deep to cut the roves. 6mm * 6mm is about right. Then using the West epoxy system with the brown filler ( forget the number but it is the easily sanded one) fill the groove. To do this use a putty knife with the pointed end ground to the radius of the fillet that you want- about 10mm radius. This is better than sticks as you can collect the excess with the flat edge of the knife as you go & work quite quick
Not sheathing the outside is done to allow the wood to breath. I was able to cover outside because i had a low moisture content
If you do sheath the outside it is very difficult as when you push the cloth into one recess it pulls out of another. You also have to place the cloth with the weave diagonal to the lands. Max area of cloth per go is about 1 M2. It is also best to have the hull upside down so the excess resin runs into the land not away from it.
If i had know that I would have turned the hull ( yes even with the 1.25 tone keel attached) upside down. You could of course try 6 inch wide tape & run along the plank
Because of the effort & skill needed to apply the cloth to a clinker hull I would be surprised if your boat does have any mat - I would suspect that it is just a resin probably applied by roller

Contact Wessex & they will tell you about the resin
 
I take the view that you either need to dry and seal the wood adequately, or the grp needs to virtually replace the structure of the boat, not just be a waterproof skin.
If the GRP is indeed 'hefty', then you are probably not too concerned about losing some strength from the timber.
I would look into drying the hull as much as possible and applying a wood preserver.
I've heard of some people in the US using a waxy preserver to good effect.

Unfortunately it all comes down to cash. If you follow the advice to strip off the 'nasty' grp, you are in for a big bill.

Do not touch that without a serious talk with a good surveyor or shipwright.

I know of at least one usable sheathed boat that was stripped of its sheathing and never went to sea again.
Another that just needed a new plank which would probably cost about £2k if that's beyond your DIY.
And at the end of the that, you'll have the same high maintenance old boat. Maybe better to get 10 enjoyable years out of it at reasonable cost.
I haven't seen your boat, so I'm sorry if I'm doing it down.
There were some very badly sheathed boats years ago which fell apart in due course. This has given the concept a bad name.
But in some cases it is an economic way of getting another 10 or 20 years out of a hull that is basically 'time served'.
I would suggest declaring war on the rain water ASAP.

A few years ago I 'saved' about £10k by buying a wooden racing boat instead of a GRP one. I then spent £12k on a garage to keep it in. That worked out well TBH.
Good Luck, and don't forget it's only about 92 days to launch time.
 
Another approach would be to add a few layers of matting and solvent free epoxy resin on top of the outer (probably polyester) cladding. Resin thickened with bonding powder would drain off and you could then be sure about the structural strength of the hull. It all comes down to how attached to the boat you are, how much you wish to spend and your DIY skills. Lots of good advice already about the inside of the hull.
Good luck with it-you are embarking on a steep learning curve!
 
lw395 said:
I take the view that you either need to dry and seal the wood adequately, or the grp needs to virtually replace the structure of the boat, not just be a waterproof skin.
If the GRP is indeed 'hefty', then you are probably not too concerned about losing some strength from the timber.
I would look into drying the hull as much as possible and applying a wood preserver.
I've heard of some people in the US using a waxy preserver to good effect.

Unfortunately it all comes down to cash. If you follow the advice to strip off the 'nasty' grp, you are in for a big bill.

Do not touch that without a serious talk with a good surveyor or shipwright.

I know of at least one usable sheathed boat that was stripped of its sheathing and never went to sea again.
Another that just needed a new plank which would probably cost about £2k if that's beyond your DIY.
And at the end of the that, you'll have the same high maintenance old boat. Maybe better to get 10 enjoyable years out of it at reasonable cost.
I haven't seen your boat, so I'm sorry if I'm doing it down.
There were some very badly sheathed boats years ago which fell apart in due course. This has given the concept a bad name.
But in some cases it is an economic way of getting another 10 or 20 years out of a hull that is basically 'time served'.
I would suggest declaring war on the rain water ASAP.

A few years ago I 'saved' about £10k by buying a wooden racing boat instead of a GRP one. I then spent £12k on a garage to keep it in. That worked out well TBH.
Good Luck, and don't forget it's only about 92 days to launch time.
Click to expand...

+1 for LW395 's advice - covers to keep rain out - timber preservative on inside - use the boat as it is & save your money for a GRP boat if & when it dissolves.
Good luck Jim
 
Daydream believer said:
This may or not be of use to you
I sheathed a Stella 16 years ago & in spite of doubters it is still perfect & does not leak a single drop of water other than via the stern gland. ...
Click to expand...

I suspect that very little sheathing is done with the level of care and attention you gave to it, though of course when it is done that well the results can be excellent and long-lasting.
 
I'm going back, but a friend had a Richmond Slipways clinker motor cruiser with small steadying sails. It was GRP sheathed below the waterline. In the 5 or 6 years he had it nothing obvious came to light as to why it was sheathed, & he went between the upper Thames and the Medway several times over the years. Whilst the reputation of wooden GRP sheathed boats was that it got another few years out of them before they had to be scrapped, we felt this boat had been sheathed when the planks were in good condition, not sure why, but didn't seem to done it much harm.
 
My advice would be that if the sheathing is sticking on ok then to leave well alone but it is important for rainwater not to lie in the hull, as has been mentioned before. There are a few problems with a sheathed hull though: It is difficult to carry out any repairs because the heads of the fastenings are hidden; The hull weight will now be much greater; you need to ask yourself why the hull was sheathed in the first place?
If the boat is worth it why not strip the cladding off and repair her properly?
My first Redwing had a grp clad when I bought her in 1978. I stripped off the grp in the early '80s and probably saved her life. She is still in use and now after a recent restoration is beautifully varnished and sails in the Isles of Scilly Redwing fleet.
 
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