Teredo Navalis: problem or not?

[Yahti]

Teredo Navalis: problem or not?

I'm 55 yo and next summer retirement pension. I have a dream - or more accurately - i have two dreams.
1) cruise round the world
2) do it by woodenboat ( my purpose is have made bigger one smile.gif

But i have a problem; teredo navalis! Does any know is something method wherewith possibility of teredo navalis can eliminate? In Finland we have not enough knowledge about this issue. We do not know have any producer something impregnant or similar 'poison' what i can put on the wood? We do not know is teredo navalis true problem, or when teredo navalis become problem? Or what i can do/fight for it?

Can somebody help me and give particular knowledge about this?

Mr. Yrjö Ahti (Finland)

[ 11-15-2004, 10:04 AM: Message edited by: Yahti ]

[Ian McColgin]

Firstly, shipworms are by no means confined to the tropics. The pilings in Boston Harbor are quite infested. I had damage to the crush block at the leading edge of my keel and they entered there. Fortunatly, the crush block is small and there was a barrior of epoxy and paint between it and the rest of the stem, so the damage was confined. We had one boat in Hyannis that just riddled with worm.

It's easy. Keep the bottom paint in good condition. If you take the ground, especially in warmer waters, inspect and seal and damage promptly, even if the seal is at first only a fast patch of underwater setting epoxy.

Enjoy the cruise.

[Mrleft8]

Paint. Apparently they don't like to chew through paint. Some put a sacrificial "worm shoe" on areas of high wear, which can be replaced when toredos infest it. I believe there are a few fairly impervious species of wood as well...Teak is one I think.

[Ian McColgin]

Teak is indeed fairly 'worm proof.' I might add that if you prime/seal a wood hull with CPES, you've not only created a good barrior buy you've also spread lovely toxins deeply into the wood that will deter rot as well as worm.

[Andrew Craig-Bennett]

Sorry to be the bearer of bad news, but teak is by no means impervious to teredo worm.

I have a piece of teak, given me by Jerry Sousa, who posts on this board, taken out of Hong Kong harbour. It is about 8" x 4" x 2" and was clearly once part of a vessel. One side looks perfect - the other three are absolutely riddled with teredo holes; in several places the "mouth" shells are still visible in the tunnels.

[Magwitch]

Yup, keep a good paint cover, that should do it. Watch out also for gribble in cold waters, again paint is the answer, unless you feel the need to have the hull copper covered. That works too.

IanW

[Mrleft8]

I guess that faster "plantation grown" Teak has less of the oils that resist decay and worm attack. I would also guess that any hull made from Teak these days would be made from that faster grown stuff.....

[Venchka]

I'd risk worm damage to have been pensioned off at 56.

As a good cajun friend used to say, "Somethin ain't right." :D

Wayne
In the Swamp. :D

[ 11-15-2004, 02:50 PM: Message edited by: Venchka ]

[paul oman]

all the epoxy chemists I have worked with take great care not to touch the epoxy with their skin but none worry about fumes.

paul oman
progressive epoxy polymers

[Yahti]

OK. My worry seem vain, or what? If i keep "skin" in paint, 'teredo worm' is not so big problem as i be afraid.

"Wooden boat is wooden boat, other boat is other boat", as we say in Finland ;)

[Gary E]

Those who mentioned a sacrifical worm shoe or crush block are right on the mark. We would nail on the worm shoe with 2 layers of roofing or tar paper between the cheapo board and the keel. Then to further discourage the little pests, we added a large dose of fine ground cayenne pepper to the soft copper bottom paint. This would allow us 2 yrs between bottom jobs in the New Jersey area. I wonder how well it would work in Fla. I never used the harder paint, so I dont know if it worked the same way.

[Ian McColgin]

Hurray! Another for ceyanne in the cheap paint!

On epoxy: The chemists who first taught me about the stuff back in the early '70's were always more concerned about breathing the keytones than skin contact. It's now clear that John Gardner's lonely voice in the National Fisherman back then was right, both skin and lung risks are real - managable and epoxy's great stuff, but real. The fume risk is easily handled by good ventilation unless you're spraying or unless you've got an extra sensitivity, but epoxy fumes are a hazard.

I am not sure exactly which solvents or whatever in CPES go so deeply into the wood. All I know is that four years after some CPES had been put on the surface of a keel, there was cause to bore for new keel bolts. Not the world's largest keel but centerline holes - about 6-1/2" from the surface and this means cross grain, not wicking up end grain - produced debris that smelled distinctly of CPES. I made the assumption of toxicity but I didn't actually put a toredo or something in a nest of the shavings to see what happened.

[sdowney717]

bottom paint is a high maintenance item. Just imagine millions of microscopic larvae swimming around looking for a crack, chip or peeled off area of paint. The planks will flex, the hull will be scraped or scratched, the paint film will break and they will find their way in. You need a better solution than paint. Bottom paint is generally a weak coating to begin with, it will crack or scrape off or wear away. You need to seal that hull either sheath it with epoxy and cloth or coat it with a polyurethane liquid rubber sealant such as sanitred permaflex. www.sanitred.com (http://www.sanitred.com)

You dont want to be constantly worrying about worms which can and have sunk many wooden boats. Once they start getting in, more will find easier access and the problem will develop real fast. In only a few months in warm tropical waters, these worms can eat up a lot of wood.

[rbgarr]

In addition, IIRC, I read that the Pardeys coated Serrafyn's underbody with creosote before painting the bottom to help prevent worm infestation. I don't know whether that is legal where you are, or whether CPES would be just as effective.

[lagspiller]

Yahti, I am a bit surprised you haven't run into the worm in Finland - I have certainly seen it here. Luckily, in a 'sacrificial keel' attached under the real keel of a friend's small open workboat. This got skuffed up by landing the boat and there was a real beast of a worm that had tunneled out about a meter of wood - probably at least 1/2 cm dia.

What saved the boat was a trick the builder used... a layer of something impervious between the keels. It was some years ago, but I believe I remember it was a unbroken length of tar-paper or asphalt-coated paper. The worm turned when it hit that and continued down the length of the sacrifical keel. None of the other areas which were coated with paint or Benar were damaged.

[PeterSibley]

If you get as far South as Australia, take the worm VERY seriously ,especially if moored in rivers or estuaries.

As an aside I have sheet lead between my worm shoe and the stern timbers,let them try to chew through that.Gawd...I hope they can't :(