Tartan 3400 Cored Hull

[Rustyf]

Does the fact that the 3400 has a hull cored with polyurethene and not balsa mean that it is not susceptible to problem of moisture seeping into the hull and wetting the balsa of a balsa cored hull? Seems to me that the water would not wick through the polyurethene as it would with balsa. Thanks

[tommays]

Well

Tough boat to get a answer BUT the core material does not matter if gets wet its wet and your screwed

[sailingdog]

Rusty—

That is a common misconception. There are three commonly used core materials—end grain balsa, ductile PVC foam and rigid PVC foam. Yes, some companies used marine plywood for a while, but it really is not an appropriate core material, as I've written about on my blog.

The problem with end-grain balsa is that it tends to rot if water gets in... then as it rots, the cored laminate delaminates. However, end grain balsa tends to keep water intrusion localized until it starts to rot, due to the orientation of the end-grain balsa.

The problem with the PVC foam, both ductile—like Airex and rigid—like Divinylcell—is that they allow water to migrate long distances and can delaminate over great areas rather quickly under the right conditions. While PVC foam doesn't rot... the fact that the fiberglass skin can separate from the foam over a wide area fairly quickly means that the laminate is compromised.

Originally Posted by Rustyf

Does the fact that the 3400 has a hull cored with polyurethene and not balsa mean that it is not susceptible to problem of moisture seeping into the hull and wetting the balsa of a balsa cored hull? Seems to me that the water would not wick through the polyurethene as it would with balsa. Thanks

[Rustyf]

Thanks Dog. As usual your advice was very helpful.

[PCP]

Originally Posted by sailingdog

Rusty—

There are three commonly used core materials—end grain balsa, ductile PVC foam and rigid PVC foam. Yes, some companies used marine plywood for a while, but it really is not an appropriate core material, as I've written about on my blog.
....

Congratulations, that's a great article, I mean in your blog, clear and very informative. I have learned one or two things. Didn't know about the thermal problems with the epoxy resins...and that suggestion of a finish in light colors makes a lot of sense. I have seen that many times epoxy boats have light colors (the Hanse for example) but I didn't know there was a reason behind it, other than aesthetics.

[mitiempo]

Tartan is using epoxy and post curing at high temperature which is a lot better than using polyester at room temp which used to be how this was done by builders coring hulls.
I just read Tartan's online blurb about the construction and they state they don't use the "weak and heavy chopped strand fiber that dominates the leminate of other builders." Do any builders actually use chopped strand on boats of any size now? Every builder says they don't but everybody else does.

[JimHawkins]

Tommays, tell us more about that boat and all the holes drilled into it.

[sailingdog]

Thanks... :-)

Originally Posted by PCP

Congratulations, that's a great article, I mean in your blog, clear and very informative. I have learned one or two things. Didn't know about the thermal problems with the epoxy resins...and that suggestion of a finish in light colors makes a lot of sense. I have seen that many times epoxy boats have light colors (the Hanse for example) but I didn't know there was a reason behind it, other than aesthetics.