Teredo worms

[Chief Engineer]

Once you machine it in any way don't you lose the protection? i.e. sawing, sanding, drilling, planing?

Unless you are going to build a box like Noahs...Ark....

Is there something you are not telling us Mr. Gore?

[wildshore]

Just as a note, most pressure treated lumber sold in the US is treated with ACQ - Alkaline Copper Quaternary--which is toxic to marine organisms. The older compound, Chromated Copper Arsenate (CCA) was banned for use in homes due to the arsenic content, but is still allowed for piers and other marine applications as it is somewhat more effective, but both should increase your protection if used in conjunction with a good barrier paint and antifouling bottom paint.

[wildshore]

"Once you machine it in any way don't you lose the protection? i.e. sawing, sanding, drilling, planing?"

Actually, not really. Pressure treated lumber is pretty well saturated with the compounds.

[wildshore]

and, just as another point of info, the "tanalith" treated wood referred to by some of our Aussie friends is the brand name for copper triazole impregnated wood, similar to ACQ in that it contains no arsenide or chromium, but perhaps a bit more concentrated. All three, CCU, Tanalith, and ACU work pretty well in stopping wood chomping marine organisms, or at least in giving them indigestion......

[Capt Phil]

We used to use plain old untreated Doug' fir planking on the seine and towboats I worked on in the PNW years ago. Traditional caulking with cotton and oakum and soaked in 'red lead' bottom paint. Every year we would replace a couple of planks and over several seasons probably replaced the entire bottom. Bottom paint kept toredos at bay but the stuff we used is pretty well banned now. Wonder we aren't all dead! Phil

[minaret]

Originally Posted by Capt Phil

We used to use plain old untreated Doug' fir planking on the seine and towboats I worked on in the PNW years ago. Traditional caulking with cotton and oakum and soaked in 'red lead' bottom paint. Every year we would replace a couple of planks and over several seasons probably replaced the entire bottom. Bottom paint kept toredos at bay but the stuff we used is pretty well banned now. Wonder we aren't all dead! Phil

You mean like this? Just done...

[hellosailor]

Once you machine it--that's actually one reason they stopped using arsenic. Arsenic from the sawdust and shavings, into the garden, into the food...I'm not sure if the new stuff is hazmat as well.

[Capt Phil]

Exactly like that, Minaret... your photo takes me back! Cheers, Phil

[minaret]

Originally Posted by Capt Phil

Exactly like that, Minaret... your photo takes me back! Cheers, Phil

Thought it might. The old ways are still alive here.

[Capt Phil]

Hey minaret, we may be the last of a dying breed! There is an old seineboat tied to the government dock up in Egmont, BC called the Silver Sides that I probably replaced the whole bottom on at least once. She was an old but sturdy girl when I worked on her in the 60's! Glad to know she was still afloat a couple of years ago. Did it all... west coast trolling, gillnetting, seineing, both drummers and table seines, towed logs, flat and bundles, barges, floatcamps, beachcombed for a summer... what a life! Learned a lot and hooked me on the water. That shipyard in Port Townsend up your way is one of the centers for wooden boat lovers and builders. Love those Nauticats, by the way... the old owner of Baja Naval shipyard in Ensenada had one for years and he used to take her down to the sea of Cortez every year. Phil

[DumnMad]

Originally Posted by wildshore

and, just as another point of info, the "tanalith" treated wood referred to by some of our Aussie friends is the brand name for copper triazole impregnated wood, similar to ACQ in that it contains no arsenide or chromium, but perhaps a bit more concentrated. All three, CCU, Tanalith, and ACU work pretty well in stopping wood chomping marine organisms, or at least in giving them indigestion......

Have to make sure the treatment is for permanent immersion in sea water. It needs to be softwood for full penetration.(e.g.Pinus Radiata H6 treated.) Wear mask & gloves when sawing, sanding or shaving. Would only need it for the outer layers. Above the waterline use lightly treated timber. Inside use minimum treatment for fungus resistance. Probably best use would be for a barge.

[SkiprJohn]

The answer to your question is yes. I had a friend that built his boat of pressure treated lumber and toredo worms got into it so severely that he was forced to use copper sheathing. I was able to put my finger through the 2x hull at haul out and it was a wonder it didn't sink at the mooring. Then the maintenance got to be too much for his age and he finally gave the boat away then it sunk at its mooring. Buehler designed Juno. A fine sailing cutter but did not last.

The tropics are a bit harder on wood hulls than northern or extreme southern waters.

[haw1961]

The old wooden boats that I worked on all had a worm shoe that we replaced when needed. Most of them were oak frames, mahogany planks, and pine worm shoes. Worked good in the midlantic area. I don't know how it would work in the tropics. That was pretty long ago. I think most have been glassed by now.

[gjordan]

There may be some pressure treated marine grade wood that I dont know about, but the pressure treated wood from the local lumber yard is usually a poor grade of wood that has been treated with chemicals to make it last a while longer. As far as machining it goes, if you simply cut a pressure treated 4 by 4, you will see that the treatment does not penetrate very far at all. A poor grade of wood and a few nasty chemicals will not build a good boat._____ My 2 cents worth.____Grant.

[Astrid]

One way of combating teredo was to put a second sheathing of wood over the main hull planking, with a layer of tar and canvas in between to prevent the teredo from attacking the actual hull planking. I assume this is the same or similar method to what haw1961 referred. It was commonly used on merchant ships before coppering became common. It needed to be renewed from time to time, though, so it was an ongoing maintenance routine.