Cored Hull

[KestrelBuck]

Does anyone know definitively whether the Tartan 42's were built with a cored hull below the water line? Is there a place where I can find out this information? There was a thread on cruisersforum that that had this discussion about the Tartan 37, but I can't find my way back there; can you steer me to it?

A surveyor that post articles to web asserts that there is no non-destructive way to test for water intrusion and rot in a balsa cored hull. Is there a surveyor out there who could comment on this?

[GordMay]

Greetings and welcome aboard the CF, KestrelBuck

According to the brochure, Tartan used “contour core” in the T42 hull.

See ➥ http://www.tartanownersweb.org/models/t42/T42broch1.jpg

From ➥ Welcome to the Tartan Owners website

[KestrelBuck]

Thanks Gord. I was aware of the TONE website. The reason I posted my question because a cored hull can mean different things. It could be cored from the water line up, as was the case with my 1988 Pearson 31, or it could be cored below the water line as well. The Tartan 42's were built form 1980 through 1984. This was a period of transition in the industry in the coring of hulls, so it remains to be seen just what a cored hull meant to Tartan at that time and whether they changed their practice at different times in the production run.

[Hampus]

I'm no surveyor, but the least destructive way of checking would be to simply remove a thruhull and have a look. Even if it is cored and sealed (core removed around the thruhull and sealed with epoxy to prevent water intrusion), at least you'll know that much. If it hasn't been sealed you'll see the condition of the core. When inspection is done, all you need to do is to replace, or refit, the thruhull.

/Hampus

[delmarrey]

Originally Posted by KestrelBuck

A surveyor that post articles to web asserts that there is no non-destructive way to test for water intrusion and rot in a balsa cored hull. Is there a surveyor out there who could comment on this?

I'm not a surveyor but Hammer tapping will tell an experienced surveyor weather there is water or not in a cored hull. I know I can. As for rot that's a different story. Drilling a small hole would be the way to check. BTW - Some cored hulls are not balsa, but foam. Some foam cores may dry out enough to be OK but balsa may never dry out.

[amarinesurveyor]

I don't know if Tartan 42 hulls were cored, but you can usually tell by looking on the interior of the hull in areas where it is visible, by looking for areas where the inner skin bumps out indicating a thicker section of the hull, and you can tell if it is solid by tapping with a hammer (percussion sounding). My guess is that if it is cored, it is balsa.
Brian

[GordMay]

BTW: The term ‘contour core’ generally means that the core, whether balsa or another core material, has a series of cuts through it. Typically these cuts run perpendicular to each other along the length and width about 1" to 1½" apart, forming a grid of blocks that are held together by a loosely woven cloth scrim.
This allows the core to follow curvatures in the hull or deck, whether convex or concave.
One problem in using contour core is that the blocks of core will separate to some varying degree, in conforming to a curve. The resulting gap must be filled to prevent water migration within the deck or hull.

[sailvayu]

I am not sure about your boat being cored but I would look at the thru hulls from the inside and see if they are recessed around the fitting. If installed correctly in a cored hull they should be, does not mean they are installed correctly. I also look for screws on the inside securing wire ties and the like often these are a clue that the hull is cored. If you have to your can remove a thru hull and look like the other poster suggested.

Most surveyors will use acoustic testing (tapping and listening) to tell if there is a core failure, Also the use of a moisture meter can tell you if the core is wet. If there are strong indications of a problem I will start by drilling a 1/4" hole from the inside and saving the chips from the drill to see what they look like. Black or dark is generally not good. If things still look suspicious I then get the hole saw out. You should be able to get a good idea of what is going on without starting by drilling holes. Some may suggest thermal imaging but I have found doing the tap out and moisture meter turned out to be as accurate or more accurate. And trust me I did some extensive testing before totaling 2, 1.5 mil yachts due to core problems.

good luck

[Joli]

Why not call the factory?

Tartan Yachts Model

Or as other have said you can look inside the boat. Look to see if the balsa has been relieved where through hulls are situated. Or look at the keel area, the balsa will be removed there and it will taper to solid glass.

Our, new to us boat, threw me when we surveyed personally. It has 2 layers of balsa and it took a bit of poking before I figured it out. I don't worry about balsa below the waterline if the boat is built correctly though.

[KestrelBuck]

Thanks everyone for your thoughtful replies and good ideas. Having spent three hours going through the boat I have decided to pass on it.

[rickwrinkley]

I have only just joined this forum so a late reply. surveyors in aus now use a sonic tester that puts out exactly how good the hull is and shows areas of water ingress.regards RICK

[eyschulman]

Be warned sonic testing has false positives and false neg. results you still need a hammer and a good ear. And you may end up doing test drill holes where sonic results are + and hammer is neg.