Thread: Mould removal from Wooden Boat

I'm guessing that 'let it rot then build another one' isn't one of the preferred options

I've no solutions I'm afraid. Hope you get on top of it but it's a biiiiigggggg job.

Richard
looking forward to seeing some sensible answers

Howdy .. someone might come up with a better solution ... but the big problem is salt.

IT will suck moisture out of the air into liquid form making all surfaces damp.

So wash the inside of the boat if it tastes salty.

You have the traditional approaches to keeping the moisture level down right
1/ Fresh air ventilation
2/ Circulation

If you are just using the fan to move air around the boat it is useless - you need to get fresh air in, circulated around and out again. Getting items which collect salt and moisture out of the boat (sails, anchor ropes) out of the boat will help too. Leaving lockers and drawers open a little will help too. Open up the floorboards at the front and back of the bilge area too.

Maybe tarps over your hatches so they can be left open or fit a fan exhaust to one of the hatches at one of the ends of the boat. If you have the boat on a swing mooring the air normally wants to come out the fore hatch and go in the after hatches.

Sounds like you have electricity (so likely that you are not on a swing mooring...

With flash race boats they often use a dehumidifier - which uses electricity to circulate air and pull the moisture out of it. Depending on the capacity of the dehumidifier you do need to empty the water out of it reasonably frequently.

The dehumidifier does not need to go all the time. If the boat has a period of relative dryness on a weekly basis it might be enough to prevent problems.

Keep an eye on the planking too. I would not expect it to cause any shrinkage problem - probably the same as mooring a boat in Adelaide - but keep an eye out for plank movement anyhow.

Before anyone tells me salt is how you stop mould and mildew ... if you have salt the water will condense where the salt is. Then during the day the boat warms up and the water evaporates into the air. In the evening ... the temperature drops and you get fresh water condensation in the nooks and crannies which then rinses the residual salt toward the bilge. So you end up with beautiful moist fresh water areas around the underside of the deck and the stem and transom. You should read how bitter Francis Herreshoff gets talking about the lamentable habit of adding salt to boats in the blind hope that it prevents rot. Get rid of salt and you get rid of moisture. However ... with ship's timber that are saturated with salt water below the waterline the salt is a protective factor.

Best wishes
And she is a fine little ship!!!





Link
http://www.duyfken.com/

Michael Storer

Originally Posted by Duyfken

Dear All,

I am looking for an effective way to remove, and hopefully keep away mould from a wooden boat.

Yasmin
www.duyfken.com - just in case you are interested

G'day Yasmin

"Chemotherapy for Rot"

http://www.angelfire.com/nc3/davecarnell/ (original site)
http://www.simplicityboats.com/chemorot.html (cached copy in case Dave dies - he's getting very old now..)

Have found nothing to refute Dave's claims other than "our commercial brew is so much better" from corporate interests.

I have successfully used glycol to arrest mould in carpet & in wood.
Identical success to Dave with tinea (having failed with a variety of expensive prescription & non-prescription items over several years).
It works.

Another option where timber gets wet & the glycol/borax is likely to leach out is treated pine re-sealer.
CCA (copper/chromium/arsenic) used to rot-proof pinus crapiatus is a bit toxic to be supplied over the counter (or so I am told.).
CCB (copper/chromium/borate) is available to domestic users to reseal treated pine where it gets put in the ground or wet places. Landscaping suppliers who deal in treated pine should be able to sell you some. With a lot of area to cover, you could approach the manufacturer/s for bulk discount. With appropriate traning/whatever, you may even be able to get CCA.

NOTE: CCB PERMANENTLY STAINS THE TIMBER A GREENISH-TAN.... TEST ON SOMETHING INCONSPICUOUS FIRST !!!
Even glycol anti-freeze concentrate has so little dye in it that it doesn't appear to discolour wood.


I used CCB to rot proof a pair of little kayaks I built from cheapo pine plywood. I later turned them into a miniature cat. So far have lasted 8 years without any rotting whatsoever.

If she were my ship, I'd give her a good soak in glycol to kill the bugs, then a good soak in CCB to prevent further events.

And make sure no small children suck on the timber for long periods.

cheers
Alan J.

Howdy ... AJ,

I am not sure but I have read that there may be concerns about these products in confined and inhabited areas?

Also I would try more direct methods before painting the whole interior of the boat with something that may or may not work.

Ventilation and circulation - getting wet stuff out of the boat - washing the interior down. Worth trying in the first instance.

Is anyone up with this? Maybe Carnell's site goes into this as well and I am thinking of something else.

MIK

Its 9 year to the day that she first set sail.
And YOU'VE ALREADY BROKEN HER!!!! Only Joking!

I know nothing about wood rot, so I can't help.
But I do live in Freo(where she was built) and I did witness some of the construction.
So bring her back home, and remember to fill up the tank before you give back the keys.

Cheers

Mickj

PS - She is a very pretty boat

Originally Posted by Boatmik

Howdy ... AJ,

I am not sure but I have read that there may be concerns about these products in confined and inhabited areas?

MIK

G'day MIK

As I see it, there are concerns about nearly all materials in confined & inhabited areas. For example, my neighbour's ex's doctoral thesis was on radon gas in european homes. Google radon... - breathing is bad for your health...

The way I read it, Yasmin is looking for something for the hold rather than accommodation spaces, so human contact is likely to be occasional rather than extended. Proper ventilation should take care of the rest.

Agree that ventilation & dryness is the preferred means of preventing mould.
However, for Duyfken, it is too late for prevention. They have already got it & need to kill it. As far as I have read about it - internet hunting, not formal thesis research - glycol is probably one of the least toxic to humans of the really effective options to do this.

As for the CCB - again, on the assumption that it is a stowage space rather than accommodation space, it shouldn't be any worse than CCA pine playgrounds for kids, or a host of other occasional human contact applications. Probably even less of an issue with the arsenide replaced by borax. If it were accommodation space, you'd want to cover it with something (which, unless it were epoxy, would likely outgas something else toxic anyway... )

Funny to see "Oil of Cloves" recommended as a mould killer. Only other place I've seen it mentioned was in "Marathon Man" (the book) where it was presented as a local anaesthetic for toothache... versatile stuff !!

cheers
AJ

Hey we haven't broken her!

No we are not on a mooring, we are in the Cairns Marlin marina, we have electricity.

It is a living space for people, our crew sleep in the hold, we are not a big ship we don't have any cabins for crew, so something that is non poisionous to humans is preferable.

We can keep the gun port hatches at the rear of the ship open, and the fans keep the air moving from there, out the front.

The mould has definately got better with the arrival of the dry season and the lack of humidity in the air.

Unfortunately washing the boat down with fresh water is not an option. Fresh water is causing a lot of our problems here in cairns. The ship gets a salt water wash everyday.

Other than that we have done as you already suggested and removed as much equipment (sails, rope etc) as possible, to allow more air movement and so they dont rot also.

Our other solution is not to go through another wet season, I just thought I would see if there was any other ideas that you might have about the mould removal.

we were also concerned about our crew health, with all that mould and the spores in the air etc. We moved them all out during the wet season.

Yes cloves are good for toothache, they are a analgesic, like aspirin you can chew them, they taste pretty nasty or us the oil. That was one of the reasons Duyfken was over here in the first place, looking for cloves to take back to the Netherlands.

Thanks for your help!

Interesting thread. I get the impression there are two different issues running here, one about preventing fungal decay of wood (rot); and the other about preventing surface mould (like the mildew on the bathroom tiles). Although they are both caused by fungi, I'm not sure the cure is exactly the same in both cases. I think that Duyfken is asking about preventing surface mildew, which is a common problem for boats in the tropics, and usually looks something like this:



Glycol has certainly been suggested by many folks (notably Dave Carnell) as a way to prevent rot in wood. It soaks into bare wood readily and appears to bind to the wood fibres. This is important to note, because glycol is both quite volatile (it will evaporate off the surface - in other words dry - fairly quickly) and is also very soluble in water, so it will quickly disappear off any surface that is regularly washed with water. So while it might prevent rot in the timber, I don't think it will prevent mildew forming on the surface (but I could be wrong!), it might also behave differently on bare and painted wood surfaces. It's also quite toxic if ingested, although it appears to be much less so via dermal exposure. In a very poorly ventilated space long term exposure to glycol in the vapour form may also be harmful.

CCA and borate-type treatments are also aimed more at preventing rot than mildew growth, but they may discourage surface mould on bare timber. Might be worth an experiment!

Personally, I think preventing mould/mildew in the tropics is one of those things that will always be an eternal battle. Condensation will form on surfaces, and mildew will grow. Ventilation and drying will help and because prevention is better than cure, should always be the first choice. Periodic cleaning with any normal bathroom mildew cleaning product will help, but just as in the bathroom (another humid environment) the treatment only lasts so long before it has to be done again. I doubt whether any of these products will seriously harm timbers of the size and nature used in DUYFKEN, most only contain a bit of ammonia or hypochlorite (weak oxidisers) to try to kill the mould already there and thus slow down its return. Keeping wet sails, cables etc out helps keep down the humidity, so that's a good idea too. If salt water is used to wash the ship, then mildew-prone surfaces should perhaps get a wipe-over with a wet cloth (fresh water) to remove the salt residue, as it will certainly promote condensation and mould growth.

Originally Posted by Duyfken

Hey we haven't broken her!

Unfortunately washing the boat down with fresh water is not an option. Fresh water is causing a lot of our problems here in cairns. The ship gets a salt water wash everyday.

Thanks for your help!

Howdy!

Glad you found a civilised use for those gun ports!!!

My suggestion was based on what they do with million dollar racing craft.

I wasn't suggesting hosing her down with fresh water. But getting all the loose stuff inside her out if possible. And wiping down all the surfaces with Fresh water. Getting the salt out of the loose stuff as far as possible.

Would always try to use a passive way of fixing first.

Or get a dehumidifier and shut the boat and leave it running when there is no-one aboard.

MIK

MIK

Hiya Yasmin,
You've found one of my hideouts! As far as I can see there's two different paths to go down here, chemicals or drying the air out. I don't know anything about using chemicals to prevent mould, but suspect that most of them wouldn't be up to a wet season in Cairns. At home, up the hill in Kuranda I light the wood stove during the wet to dry the place out, but I know that fires aren't an option on the Duijfken. I've recently acquired a dehumidier which uses a refrigerant unit to suck the moisure out of the air, much like an aircon does. A couple of portable aircon units would go a long way towards solving the problems but I don't know how you'd hide them during the day whilst people are on board for tours. I have used moisture absorbing crystals (calcium carbonate from memory) to suck up atmospheric moisture in an attempt at keeping my clothes from going mouldy in the rainforest and it definitely works but you'd probably have to buy it by the drum full every week. Say g'day to Cian for me,

regards,

Mick

Originally Posted by Duyfken

we were also concerned about our crew health, with all that mould and the spores in the air etc. We moved them all out during the wet season.

I would be too... a workmate has recently had half a lung removed due to a mould infection.
Common old bathroom mould it was. Courses of various drugs & what have you didn't kill it.
In a wholly remarkable moment of sanity, I *didn't* suggest glycol in a vapouriser !!
Poor bloke was so desperate he'd probably have tried it ! Almost 10 years living with the symptoms of bronchitis.
Removal finished up being his only option. Looked pretty gross in the photos.

Way I see it you have two problems.
First is to kill what you have. If moving the crew out is an option, then you have a lot more latitude in what you use. Anything toxic to mould will be toxic to humans, from copper sulphate through glycol & borax to various chlorine or ammonia based products. Choose your poison & concentration thereof - house-hold strength or industrial !!

Second - to keep it away.... you already know all the de-humidifying & ventilating advice.

cheers
AJ

AJ,

I would be pretty reluctant to poison the mould ... we are all related quite closely after all!!!

Dropping the moisture level will kill the mould ... then it can be wiped up.

Then if the dehumidifier doesn't work then maybe only go to Qld during the dry - not worth using chemical solutions for what might be a very temporary problem.

But if the ventilation and dehumidifier doesn't work and the boat is going to spend significant parts of its career in the wet then is the time for the chemical solution.

BTW I have no intrinsic fear of "chemicals" ... but if other methods will be effective ... why not use them.

OH ... just thought ... is the inside of the boat oiled wood? I've seen this happen in Sydney too - on boats shut up with wet sails - it is almost like the oil provides a nutrient for the mould. And it also prevents a good wipe down as there is too much wood texture.

MIK

It may be worth talking to a coating specialist (Cairns Coatings on Scott St is a good choice) to see if you can add mouldcheck to the linseed oil you're using. Linseed oil does tend to grow copious amounts of mould in the tropics. You could do a wash/wipe down below decks with a bleach solution to clear some of it up. It's not a permanent solution but does make it possible to get the mould back to reasonable levels.

Mick

Oh Hi Mick!

Yeh I was talking about surface mould not rot.

Looks like the only cure is avoidance, I was just hoping one of you guys might know of an obscure cure known only to woodworking people.

We are using some household stuff and it seems to be working quite well. It has had to be reapplied on some areas, but its got a lot better as the weather has improved.

No the inside of the hull is un-oiled. Just bare timber.

Thanks for the help

Yasmin