gel-coating a wooden boat

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Mollyfish

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Hi everyone
Can anyone please advise me. I've got a rather leaky 30' wooden, carvel-built motor boat. I'd like to coat the whole of the hull - above and below the water-line with gel coat, and also all of the cabin house (everything but the deck). Can anyone tell me how to calculate the amount of gel-coating to buy (ie. how much per m2, so that i can estimate). also, any advice on what exactly to buy would be very much appreciated.

Thankyou
Molly
 
Agreed - don't do it. It's not gelcoat you'd use anyway (which won'y go off in contact with air) but matting with either polyester resin or epoxy. It won't solve the problem - just hide it for a while - and it'll be worse when you eventually have to address what's really wrong.

Without seeing the hull, one better option may be to rout out seams and glue in softwood strips above the waterline/sikaflex below..... But I don't know what the fastenings are like .. or the wood.... or what conditions you hope to use the boat in. Most people only mat over the deck!OF
 
No, no, no.

If you want a plastic boat, sell the wooden one and get a GRP one.

Trying to coat or sheath an old hull which was never designed for sheathing is a sure path to disaster. The hull will move, the sheathing will separate, water will get trapped, the rot will set in, the boat will be scrap. And with all that resin on you won't even be able to make a decent bonfire of it. It would be like trying to wrap your house in clingfilm because the pointing needed doing and a couple of slates had come off.

Wooden boats need proper wooden boat repair techniques, not polymer bodging.

Sorry, but that's the way it is.
 
Agreed, it doesn't work.

I gel coated a clinker boat, waste of time , cracked and fell off first time out.

I then fiberglassed whole hull, again waste of time, the fibre glass wants to flex in a different way to wood.
 
Just to repeat, "DON'T DO IT!!!"

Sheathing a wooden boat is the kiss of death and will destroy your boat nearly as fast as petrol and matches!
You will never get the boat 100% watertight, and inevitably, fresh bacteria laden rainwater will find its way into the deck structure through minute stress cracks in the GRP, and the deck and hull will start to quickly rot like the soft insides of an old log, leaving the thin grp shell as the only structural component.

All Wooden boats leak a bit, it depends on how much. If you have a couple of gallons in the bilge after a rough ride at sea, I think this may be normal for the boat. If you are spending half an hour a day pumping her out when she's sat quietly on the mooring, you may have more of a problem.

The only solution, which may actually cost less in terms of cash, and maybe take a bit longer, is to strip back and recaulk the hull. If you have any persistently big gaps between the planks these can be filled with thin strips of wood, "splines" but a bit or recaulking will really improve the hull. You may find a few frames need doubling near the keel if they have cracked - not a huge job but best undertaken by an expert. This will stop the hull from flexing if the frames are a bit tired, and hence quieten down the leaks. If the deck leaks, (I'm assuming its a teak plank laid deck over plywood here) sporadic deck recaulking (sikaflex) may be in order if the black caulking is separating from the edge of the planks in a few places, and if you get the deck wet on a sunny day, the edges along the planks which dry last of all will show you where the likely problems are.

Check corners, stress points and especially under fittings like stanchions, winches, davits and cleats, which may all need to be taken off and new sealant put underneath.

If all this is too much, sell her and buy a GRP boat. But then again, every GRP boat I've ever been on has leaked, just for different reasons!

Gook Luck
 
My boat was sheathed below the waterline many years ago, but it was carried out on a sound hull, correctly repaired and prepared as needed. I have had no problems with it.

However, It will not solve a boat being leaky. A leaky boat needs re-caulking or repairing properly, not being bodged with fiberglass.

Correctly applied fiberglass and epoxy works wonders, but its very evil in the hands of a bodger. It should only be used to prevent leaks and reduce maintenance, not to solve existing leaks.
 
I think by now you should have got the message. No matter what the epoxy manufacturers say, don't do it!

You say your boat is carvel built. The seams will be either close fitted (rare), splined (a sign of quality), or caulked with "cotton string" with red-lead putty on top to fair it in to the hull (most common).

There are many reasons why your boat could be leaking. Splined seams sometimes come adrift and have to be re-glued. Caulking can fall out or rot and has to be replaced. If you can see where the water is coming in I'd start re-caulking there.

If the gaps between the planks are opening up as the boat "works" out on the waves it could be the fastenings holding the planks to the frames are tired. Big , time consuming, job!

A few cracked frames could be your problem. Check and repair as necessary.

Loose, corroded or rotten floors have been covered. Again, a big job but not necessarily a death blow to your fine ship.

Another nasty problem to check for are the bolts holding the longitudional scarfs together at the stem and stern. If they are corroded and broken the entire boat will warp which will encourage the caulking to fall out and open up the planks. A good indicator of this are the hood ends (where the planks ends are screwed or nailed into the stem and stern). If they are loose you have a problem.

I'm afraid these are just some of the problems that wooden boat owners face. Welcome to the club.
 
May I offer a practical suggestion to help with leaky decks. If you are faced with a large deck that is leaking badly and its getting a bit late in the season then you could paint your decks with chlorinated rubber paint. This is very flexible paint and drys quickly and will cover cracks and stop leaks. View this as a temporary solution and as you get time you can sand off a small section at a time of the decks and seal them in the traditional way. I suppose not everyone will agree with this but I know several people who have done this and it did work.
Good luck.
 
thanks everyone....ok, i promise not to touch the epoxy! The rubber paint sounds good alan. does it last long? maybe i could paint the whole boat with that. How does it perform under the waterline? could you recommend a supplier? rubber paint sounds ideal for my level of know-how.
 
Hi Mollyfish.
As a wooden boat owner myself, with a professional boatbuilding son, I can say that there's nothing, and I mean NOTHING, that you need to do on your boat that you can't do.
OK you may need 2 people to do some jobs, like tightening the copper nails/roves. But really if you can use a saw, plane, drill, screwdriver, sandpaper, etc. then you can do everything that's needed. All it takes is time.
Please treat the flexible rubber solution as a really temporary fix, like weeks or months.
If the caulking needs re-doing in some places, get the tang of an old file, the pointed bit that sticks into the handle, and heat it a bit and bend it into a hook. Then using an ordinary bench grinder grind the hook so it's a scraper that fits into the gaps between the planks.
Then you can spend happy days this winter cleaning out the old caulking and putting in new.

It really is amazing how much a boat will 'take up' and tighten when in the water. You don't have to seal every tiny crack.

I had GPR boats for years. Even fitted out a hull/deck, and I can honestly say that wooden boats are easier to look after. GRP goes on for years, but when things start to go wrong, boy do they go wrong!
With a wooden boat you could re-build the lot if you had to. I've seen my son do it with very little help.

So please, get her ashore this winter and make a short, yes short, list of jobs in priority order. If all the list doesn't get done, there's always next winter!

For the bottom my boat had "two coats of bitumastic and one of antifouling..." when new (1960) and it's still sound.
I've seen this used recently on an old boat and it worked well.
It's not a substitute for good seams and decent caulking, but does help with the small cracks.

Sorry for the lecture. :-)
Just don't think any job is beyond you - it's not. Just takes a little longer.

All the best,
Ron
 
I have to agree with YachtEmily. Most jobs are relatively simple, just time consuming; which is why they tend to be expensive when you pay someone to do the work.
I would suggest you prioritise the work as follows:
Deal with any structural issues that compromise safety. You don't want the keel falling off or a chainplate pulling out. Hang on, your a motor boat so think of something else.
Deal with the worst of the below the waterline leaks.
Deal with topside and deck leaks.
Get as much seatime in her as you can. Rest assured, unless you are a total and utter numpty, you are unlikely to make the situation worse.

FWIW Mariposa took about 3 months to fully take up as she had been out of the water for several years. The first 48 hours were the worst. after that it was just steady improvement. She now makes an inch or so a week but, hopefully, I've identified where from and I intend to fix a few weeps this winter.
 
[How does it perform under the waterline? could you recommend a supplier? rubber paint sounds ideal for my level of know-how. ]

Is this Chap 4 real
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Yea /forums/images/graemlins/smile.gif

For the bottom my boat had "two coats of bitumastic and one of antifouling

can you tell me more about the bitumastic ?
is it just bitumastic paint?
 
My first boat was a [slightly] leaky wooden boat. I used Synthaprufe, a sort of chlorinated rubber bitumen. It worked excellently, but was a bit of a pain to remove when I eventually wanted to.
I think it's still made by Ruberoid, probably available from proper builders merchants or roofers.
A slight drawback that it bleeds through other paints so the colour will change.
I tried to overcoat with white antifoul which went bright pink fading to khaki.
Referred to locally as best gasworks enamel.
Good stuff though.
Dan
 
Bitumastic...
No idea.That quote was from the original brochure published, I think, in 1959.
But the stuff I saw being used recently was just plain ordinary bitumous paint from a builders merchant.
Dead cheap too.
The chap overcoated it with white undercoat to seal it before the antifouling.

Ron
 
Jesus. It sounds like you are all the sorts of guys I buy boats from.

I spend hours and days getting back to real woodwork and proper maintenance.

Bodgers of the world unite.
 
Bodgers of the world unite. ...:)

Actually im no Bodger!

But frigin antifoul is Very expensive and i heard that red oxide was poisonous to an extent.....
if it didn't work so id get a little bit o weed growing...oo dear the end of the world!

Joke!...Peace!...:)....:P
 
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