Killing rot in planks

[Gary Fox]

I have been scraping paint off the pitch pine planks, and found a couple of soft black patches, quite localised.
There is zero chance of a replacement plank, at least this year, so it will be repaired, patched, or bodged somehow. A foot or so below the waterline.
I would scrape off the paint, and the top layer of rot. Then I would try and get it a bit dryer with a hot air gun, and paint on well thinned PVA, to get it to soak in. Then it soaks in and goes hard.
This technique has worked well previously to repair scars and scratches, but I have never tried it with rot.

Anyway, my main question is: Do any chemicals exist which biologically kill the rot, which I could apply at some stage, to possibly exterminate or cripple the rot? I am expecting the answer 'No' but might as well ask.

This rot is caused by lack of use during lockdown, and fresh rain getting under the paint, probly similar stories in every boatyard..

 

[northwind]

Bonda wood hardener, will help to stabilise the wood but once the rot has started you are just delaying the enviable

 

[sfellows]

Make Wood Good - Not cheap but appears to work. The owner will advise if you call him.

Make Wood Good: Clear Penetrating Epoxy Sealer-CPES, UK Europe.

 

[Poignard]

Have you thought of fitting graving pieces?

GRAVING PIECE REPAIR - YouTube

 

[TernVI]

If it's going to be out of the water for a while, a normal wood preserver would help to some extent.

 

[Gary Fox]

Have you thought of fitting graving pieces?

GRAVING PIECE REPAIR - YouTube

Yes, in an ideal world, all other things being equal, I most certainly have, and ideally I would prefer to; got to be a bit careful, it would need some extra blocks to strengthen from the inside, and a few rivets replacing, to maintain the strength.
Just want to get her back in the water and go sailing, mainly, and postpone proper repairs, as it is not 'an ideal world', she and I will both rot away, unless we can get some blue-ish water under us..

 

[Laminar Flow]

You can use the green coloured preservative used for treating cuts on pressure treated timbers. It is an effective biozide used to treat what is the really quite inferior wood used for pressure treated structural timber. The agent is effective enough for the manufactures to guarantee 25 years of rot protection in ground contact. I don't think I would recommend it for interior use.

Optionally, there is, as someone else pointed out, a type of thin, penetrating epoxy that can be used to stabilize the wood. "Gitrot" is a local brand and it is recommended to drill some few small holes to aid penetration.

 

[jamie N]

I've used INTERTOX as a preventative, thus it'd stop the rot propogating.

 

[Gary Fox]

Thanks for the replies and product suggestions chaps, feel free to keep them coming

 

[Laminar Flow]

Yes, in an ideal world, all other things being equal, I most certainly have, and ideally I would prefer to; got to be a bit careful, it would need some extra blocks to strengthen from the inside, and a few rivets replacing, to maintain the strength.
Just want to get her back in the water and go sailing, mainly, and postpone proper repairs, as it is not 'an ideal world', she and I will both rot away, unless we can get some blue-ish water under us..

Wooden boats rarely rot bottom up in salt water. Getting her back into the (salt) chuck may very well stop the spread in itself. If the fungus has not spread deeply, an application of wood preservative should tide you over until you get launched.

 

[Nom de plume]

Cuprinol 5* (5 star) will be available in your local builders merchant and will eliminate any 'live' rot - get the wood as dry as poss first (that will also kill rot). It's not a permanent fix or mechanical protection but it will kill the rot and protect especially in the end grain until you can effect a proper repair.
Use the rest around the house - it's good stuff. They are pretty much all based around Permethrin and are priced according to % (ish).

 

[Gary Fox]

Wooden boats rarely rot bottom up in salt water. Getting her back into the (salt) chuck may very well stop the spread in itself. If the fungus has not spread deeply, an application of wood preservative should tide you over until you get launched.

That's what I am telling myself

 

[AntarcticPilot]

A more traditional approach might be Stockholm tar! Given what it is, it should be biocidal, and it smells nice, too!

 

[wrr]

It is worrisome to hear of rot in pitch pine, my 100 year-old windowsills are intact despite a paucity of paint at times!
In terms of treatment, borax-based chemical preparations are effective and of low toxicity to humans. I first encountered this in the San Francisco Maritime Museum, where they even insert solid rods of boron into timber.
However, it might be worthwhile to investigate whether any galvanic action has softened the timber prior to the rot. Otherwise, liberal application of borates should hold the situation until a dutchman or scarphed section can be inserted.

 

[Habebty]

It is worrisome to hear of rot in pitch pine, my 100 year-old windowsills are intact despite a paucity of paint at times!
In terms of treatment, borax-based chemical preparations are effective and of low toxicity to humans. I first encountered this in the San Francisco Maritime Museum, where they even insert solid rods of boron into timber.
However, it might be worthwhile to investigate whether any galvanic action has softened the timber prior to the rot. Otherwise, liberal application of borates should hold the situation until a dutchman or scarphed section can be inserted.

Borate gel (available in mastic type tubes) diffuses better than the rods for quicker protection. The ”green stuff” we have found at work, is next to useless in outdoor structural softwood. Bear in mind, unless the pine is slow grown Canadian fir rather than quick grown British plantation pine, it will not last.

 

[Tranona]

I repaired rot in the horn timber around the rudder tube but digging out until reaching sound timber - about 30mm deep at the deepest. Washed it out with fresh water and dried thoroughly> fortunately it was mid summer so did not need forced drying, but a hot air gun or fan heater would have done then job. Then lots of epoxy soaked in followed when cured with thickened epoxy filler - 3 or 4 layers to get back to surface level. Sheathed in glass cloth because the surround hull is sheathed.

If you have enough thickness of sound wood left beneath the rot then I think this might work for you.

 

[Gary Fox]

Borate gel (available in mastic type tubes) diffuses better than the rods for quicker protection. The ”green stuff” we have found at work, is next to useless in outdoor structural softwood. Bear in mind, unless the pine is slow grown Canadian fir rather than quick grown British plantation pine, it will not last.

Slow grown Norwegian, now unobtainable. Boat built 1957, this is the first bit of plank rot, the rest is hard; it is lack of use and fresh water, due to lockdown. That will be changing though, I have been locked out of the yard of course.
Thanks to you and the others for the tips.

 

[Keith 66]

Git rot = Snake oil. The rot dont git all it does is hide it, same goes for epoxies.

 

[Little Dorrit]

I have used Eposeal 300 a low viscosity epoxy sealer as a protective coat and sealer on wood but have not tried it on rot. It is a 2 pack product and very viscous soaking in like water - might be worth throwing into the mix of suggestions.

 

[Gary Fox]

Thanks. It's looking a lot better after scraping the black bits and letting the plank dry in the sun. I will post some pics, my neighbour's just been craned in, so I have a clear view for a bit.