Wooden hull antifouling

[new2wood]

Having chartered modern yachts for a couple of years, I have finally taken the plunge and bought a 'project'.
She is an early 1960's Falmouth Gypsy Mk I 24ft.
I know sailing, but I know very little about yacht maintenance, especially on this age and type.
I'll have lots of questions, so I hope you're a patient bunch.
First step is taking her out the water and painting the hull. Any tips would be appreciated. Do I need a special antifouling for wood, does she need to dry out before starting, how much of the old should I remove? And probably many more.
Thanks in advance.

 

[nickolanus]

Lucky you only got 20 ft. If u have a build up of old antifouling, usually looks crusty and patchy and thick, then burn it off! (use a mask with filters and goggles) This will dry off wood. A good sand with 60 grit /finish with 80 and hull is ready for a couple of coats of antifouling primer, or you can start with a good thinned primer then antifouling primer over top. Blakes do a good underwater primer which is also an antifouling primer. Whilst burning off paint and sanding you have the delight of eyeballing at close quarters the wood, the seams, the plugs over the fastenings, past repairs etc. This is how you get up close and personal with the 'old gal' and vital for peace of mind if you are putting your life in her!!! Also a couple of coats of primer will keep her from drying out too much. This can be a problem with some woods which will shrink back a lot and open up her seams. I have just placed loads of onion sacks full of wood chips along the keel which I keep soaked with a hose, crucial in the summer. Can be laid inside as well. This was my first job on coming out after 15 years.

 

[Mirelle]

Good choice - very nice boat.

The VERY FIRST THING TO DO once she is ashore is to give her a very good wash, inside and out, let her dry through, and then rig the winter cover, allowing for ventilation with holes at each end. This is essential!

Leave locker doors open, floorboards up, hatches and doors open. You want a howling draft through the boat, if at all possible!

No, there is nothing special about antifouling a wooden hull - they foul up just the same as any other kind.

Now, removing old antifouling..

I'm going to cautiously and politely disagree with Cirrus over burning off old antifouling. Most modern antifoulings are based on a chlorinated rubber paint which does not soften and scrape off nicely with heat, unlike topside paints which do, and the fumes can be seriously bad for your health, though to be honest the way the paint refuses to come off is the more annoying point, for me.

I've had remarkable sucess with a big Sandvik scraper (it has a renewable carbide blade) and a face mask. If you leave the job for a couple of months the old paint goes dry and flaky and you can actually get the a/f off and leave the primer coat more or less intact.

If the build up is not too bad, just rub it down with coarse wet and dry sandpaper and recoat. Leave this job till last in the Spring, not because of any need to dry out, but because when you repaint the decks and topsides paint and washing water will run down and leave marks!

It follows from what I've just said that the place to start is the deck. This mayy also be a chlorinated rubber paint, if its Blakes, not if its International. Go gently with a scraper and remove any loose spots, repaint (nb, use masking tape!) and leave for a week before walking on it.

The topsides will need rubbing down with about 120 grit wet and dry, primer on the bare patches, and then ideally:

- a coat of undercoat
-filler on the dings and scratches
-rub down with about 180 grit
-another undercoat
more filler
-rub down with about 220 grit
- acoat of half undercoat and half enamel
rub down with about 320 grit
-a coat of enamel
-run down with 320 grit
-a final coat of enamel

That by the way is a counsel of perfection and not everyone bothers with the whole routine. (It does not take much longer than waxing and polishing GRP, by the way!)

It is a huge help if you can rig staging for this part of the exercise!

Having done that, do the varnish (this is the longest part of the job) then the antifouling and off you go back into the sea.

 

[twisterkai]

Isn't the Falmouth Gypsy a plywood hull?

If so, it's not generally recommended to use heat to remove paints of any variety. I remember being told once that heat can damage the glue between the veneers so the potential damage isn't worth thinking about.

If the antifouling does need removing there are propreitry chemical 'gels' (a bit like nitromors) designed for the task, but they are rather expensive - apparently they never remove as many layers as they claim, so don't get sucked in. Otherwise, as a previous poster suggested, it's using the 'Sandvik' type scrapers, which whilst being very effective are extremely hard work, but then that's 90% of boat ownership!

 

[nickolanus]

Ah what do I know? Had five of us burning off my forty foot of teak hull last winter. Came off easy. Did a little scrapeing but rekoned that would have knackered my wrists by the time i had reached other end! Sanded hull using a 7 inch sander polisher with a flexible foam backing pad to which I could stick s/paper. I used to build custom windsurf boards for a living so can handle such a tool confidently. Whole bottom done between Xmas and new year. Twas one way of keeping warm!! Though my eyes were a bit weepy from the dust as it was a problem to wear a mask and goggles without getting steamed up, but have lived to tell the tale.
My view is wherever you start is not really of much consequence. A lot depends on what you find as you look! But for me a haul out means I am paying for pontoon and for space along the quay. That is another 50% So I do bottom outside and inside. Am still there one year on!!!! Replaced all the hood ends, long job... replacing all the grown oak floors with laminated ones, long job..., checked all the frame timbers,( below waterline) one every 6 inches, inspected the rivet heads inboard replacing those with flattened out roves.....and still going on..and on...and on. The biggest drawback is having to go to work! Best advice from me is start at one end and work your way along till you get to t'other end from the bottom up. What do I KNOW.
Bon chance....

 

[new2wood]

Thanks very much for all the advice.
I think I need to digest it and then return to the forum.
Yes this Gypsy is plywood, so perhaps scraping is the best option.
Thanks again - I'll be back

 

[alienzdive]

although not a healthy option, ie toxic fumes. Not using a hair dryer type diy paint burner, but a gas flame type commercial paint stripper is a very fast way to remove antifoul. Much faster than scraping. Protective clothes and gloves are a must as burning antifoul can be quite hot on the skin. I stripped half a 60 foot timber hull in 6 hours whilst 2 other people on the other side did half the other side in 8 hours and asked me to finish off. After a bet of course.
There is definately a technique however to keep the speed up. And there is more dry sanding required than from scraping. However the lef over paint loses its integrity after the application of heat and does sand off like dust.

 

[vande9389]

Hi,

I have been reading through quite a few posts on the subject of antifouling, and I was wondering if there are any opinions or experiences with antifouling that can be applied between tides without having to haul out. Any suggestions as to the product and any advice would be gratefully received. All the products I have seen sofar seem to mandate at least 24 hrs before re-immersion.

Regards

Peter