Inside hull - Can I oil now ??

[Pelle]

Hi!
Have to ask for some advice again. My 47' motorboat Dreggen has been renovated for almost 3 years now. I have hauled her out once (nearly 3 years ago) and
plan on doing this again this spring. I have now rebuilt all bulkheads and want to start outfitting the interior. Due to lack of money, I will not be able to haul her
before a month or two. Here is the question:
Can I start impregnating inside of hull with linseed oil, terpentine and poison when she's on the water ?? The hull planking is somewhat moist (wet) , probably due to
somewhat bad seams and paint on the outside. I would very much like to get the hull done behind the wing tanks.
Can I do this despite the water-ingress in the wood, or do I have to dry out the hull first ??
The weather here nowadays: about 4-7 deg Celsius and rain, lots of it....
Inside the boat; fairly dry and about 8-10 deg celsius.

Pelle

[Rocky]

I got the pine tar and was ready to start mixing but all of a sudden I'm trying to remember why this is better than varnishing the inside.

[Art Read]

Pelle... Not sure. I'd "think" you could go ahead and oil it now. Seems to me that folks have been treating their boats with oil/tar finishes for just about, well, ever. Just can't see too many of the crusty, old timey fishermen waiting for "optimal moisture content" to slap some more linseed oil on their boats somehow. Then again, there IS that whole "oil and water" thing, so...

Rocky... Trust me. You'll know the first time you refinish and have to scrape and sand all that hard, brittle varnish out of all those nooks and crannies instead of just slapping another coat of oil on like a proper seaman... ;)

[ 03-11-2003, 03:04 AM: Message edited by: Art Read ]

[Pekka Huhta]

You will get a little of oil in the wood, but just on the surface. In the other hand the whole point of impregnating a boat is in getting the oil as deep in the wood as possible. If you just seal the surface with dried oil any further impregnation gets more difficult because new oil goes through the dried surface relatively slowly.

It is possible but not very useful. I would wait but if you can't it's better to use oil "wrongly" than not use it at all. One solution would be to impregnate now behind those wing tanks etc and the rest when the boat is dry.

Or would it be possible to fabricate all the parts for the interior now, before the haulout. You would have other things to do and still would have time to do the impregnation properly.

Pekka

[WWheeler]

What are the recipes being used? What proportions of linseed oil / turps / pine tar / eye of newt etc. Is it boiled linseed or raw linseed?

[Alan D. Hyde]

50/50.

Alan

[Pekka Huhta]

You have as many recipes as for distilling moonshine.

In Finland the basic recipe tends to be close to 1/3 of raw linseed, 1/3 pine turpentine and 1/3 of clear wood preservative for killing rot and mildew. If it's being used for a boat that's supposed to be tarred (or inside of an open boat) one would use less wood preservative (or none at all) and add more and more tar as the impregnation goes on until the tar content would be perhaps 1/4-1/3.

In Sweden they tend to use much less turps and wood preservative for the basic recipe and for tarred boats 1/3 oil, 1/3 turps and 1/3 tar.

It all depends. If the wood is soft (like pine, spruce etc.) you can use more oil and less turps because it soaks in anyway. With oak or mahogany you have to dilute the oil a vbit more. If it's cold the mixture has to be thinner. Basically you try to get as much linseed in as possible and dilute it only as much as is necessary to get it there. If the surface stops absorbing oil, you can use a few layers of straight turpentine to open the surface and go on with oil.

New rowboats can be impregnated through the board so that you spread the oil inside a boat as long as it starts to come through on the outside. Then you still put a couple of dozen coats on the outside, let the oil set for a while and tar or paint the boat. On bigger boats it's not so easy to get the oil through the board but you still aplly the oil as long as the wood soaks. For a new rowboat that can be 3-4 days, for a big sailboat you could have to apply a coat every now and then for a few weeks.

We impregnated a 13-metre traditional finnish lapstrake gaffer a few years ago. Records show that the boat got 50-60 coats of oil all over. It's a quick job doing it once, but this took a while. Later we drilled a drain hole on the bottom and found out that the lowest board, about 1" thick was impregnated with oil and tar all the way through.

Pekka

[Pelle]

Thanks for the replies so far. Good point, Art. Good explanation, Pekka.
I would like to hear some more opinions how to treat the inside of the hull. I would like to let the inside "breathe", while "sealing off" the outside with paint. Raw linseed oil will let the wood breathe, won't it ?? Is not boiled linseed intended to "close" the surface ??

Pelle