preventing rot

[fisherman]

I am looking for a method or a product that prevents woodrot. I have a 1924 oak sailingyacht and it lies on fresh water. I heard that in earlier days the inside of planking was treated with a mix of linseed oil and petroleum, but I can't find anything on this topic on any of the resources on the web. Please does anybody has some advice on this topic.

[Frank Wentzel]

Fisherman

On bare wood your best bet is Copper-Tox. It also goes under many other names from local paint companies. It is about 10 to 15% copper napthenate dissolved in mineral spirits. It has a strong odor when first applied due to the mineral spirits. Once the MS has evaporated it is relatively odorless. It is non-volitile so you won't be living in a chemical haze as you might with other organic preservatives. It is a waxy material that provides some water repellancy and is relatively non-leachable. Once it is thouroghly dry it is paintable, though you might have some bleed-through with light colors. Soak end grain thoroughly. It will take a lot because the MS based helps the toxicant to be readily absorbed. You will also find that it tends to be greedly absorbed by sapwood or other rot-prone wood. Its one of the few times that bad wood is good because it absorbs more preservative. The only problem is the wood must be very very dry. Because of the MS base the Copper-Tox penetration will be stopped dead by moisture in the wood. Good luck!

/// Frank ///

PS Almost forgot. If the green copper color is objectionable in some instances they also make a version that uses zinc napthenate as the toxicant. Logically enough the name is Zinc-Tox. The advantage of the green color of the Copper-Tox is that you can tell how good a job you are doing very easily. But at those times the color might be a problem you still have a way out.

[ 08-19-2002, 08:44 AM: Message edited by: Frank Wentzel ]

[fisherman]

Thanks for the info Frank. My boat has a varnished look on the inside, so I think I don't want anything coloured. Is the ZincTox transparent or has it a color too? If it has colour, do you know anything else?

Thanks,

Rients

[Frank Wentzel]

Fisherman,

Zinctox is water-clear both in the can and after drying. I just noticed that you are from the Netherlands (ever observant - eventually), I hope you don't have trouble geting Zinc-Tox over there. As I said, this is a local brand-name. But if you can get someone to look for the active ingredient in various rot prevention products you should be able to find an equivalent product. It is not especially toxic or reactive so I don't think that, even with the more stringent regulations in Europe, you should have a problem finding it.

/// Frank ///

[Bob Cleek]

Well, reasonable minds can differ. I'd say if somebody came up with a product that prevented rot, we'd all be using it. As it stands, and has stood for maybe since wooden boats were built, nobody has ever come up with such a product. Lots have come up with materials that supposedly do, and many users embrace these products to fuel their fantasy that they've prevented their wooden boat from rotting, but... A rot preventative really is a lot like a perpetual motion machine or the fountain of youth... they keep on looking, but nobody's found it yet.

Coatings such as described do HELP limit rot, but for my money the copper napthanate products stink and are only marginal. Products which work well on fence posts are not easily tranferred to wooden boats. Any coating that to some extent limits the permeability of the wood will work as well as the next. Your 50/50 mix of linseed oil and kerosene works as well as most any of them, is easy to apply and reapply, doesn't need stripping, and also looks very nice on bare wood.

Keep in mind that rot doesn't grow where liquid coatings are easily applied. I've never seen a plank face rotted, for example. See lots of planks rotted alongside frames and shelves and covering boards, though, if you get my drift. Coat your boat with whatever paint you want, but remember ALL coatings are water permeable to one degree or another.

The only sure preventative for rot, and likely the one that's preserved your boat this long, is AIR. The more ventilation you can get below, the better. That's the ticket to preventing rot, no matter what the guys selling the coatings will tell you. Proper care and maintenance is far more important that all the stuff you could ever paint on a boat.