Teredo worms

[haw1961]

All we did was nail a board on the bottom of the keel, after bottom painting the rest of the boat. It was the width of the keel and 3/4" or 1" and did not get painted. It worked good from what I remember. Back then it was all we knew. Again, it wasn't in the tropics.

[DumnMad]

NZ softwood, H6 treated (CCA) radiata piles are known to last at least 30 yrs, and so far doing OK in tropical waters. With a boat, unlike piles, you could haul out and put on a coat of preservative on if you want. Treatment does not penetrate hardwood so well but will go right through softwoods.
The tricky part is not durability of the timber but durability of your fastenings.

[haw1961]

The best fasteners back then were ringed monel nails. Or so that is what they told me.

[kthoennes]

Coincidentally there's a detailed write-up in the April 2013 edition of Passage Maker magazine about a 34 foot trawler built out of regular pressure treated wood (pine). Looks pretty impressive and seaworthy to me - although personally I'll stick to fiberglass.

[Astrid]

The best fasteners back then were ringed monel nails.

Still are as far as I know.

[roverhi]

In Hawaii, everything is treated. If it's not, takes about 10 years before the termites and rot have done enough damage for it need to be replaced. They used to use a pressure treatment chemical that was arsenic and copper salts in a water based mixture that left the wood green. It was primarily a surface treatment. The stuff intended for below ground use had a much heavier incrustation of the green chemical and the wood was deistressed to let the stuff penetrate deeper. Very effective but costly and probably now banned by the EPA. Dug up some of the above ground treated stuff that had been buried for ten years and it was still good wood. The untreated stuff buried with it was pretty much goo. Didn't seem to hurt people as Hawaii has about the longest lived populations in the US. They are now using a pale colored treatment that is supposed to work as well and certainly isn't as yucky to work with. Doesn't seem to be as wet as the old style pressure treated wood was. Of course, the fairly dense Douglas Fir we used to get is history. The new stuff is Hemlock and much softer and less dense. Curiously, the softer wood absorbs the treartment way better so is supposedly much longer lasting. It's still crappy lumber compared to the old stuff.

I really don't understand why boat builders haven't used treated lumber. It's light years more rot resistant than untreated lumber, except for teak. Especially since most wood boat building is cold molded or strip plank which don't need the quality of wood as carvel planked boats.

[Seaworthy Lass]

Originally Posted by Capt Phil

Hey minaret, we may be the last of a dying breed!

Not a dying breed at all . Timber boats and all the associated repair work are the norm here in Greek boat yards. 99% of all fishing and tourist boats seen are timber.