: I can't help with the carbon vs glass issue, but I can tell you
: that it is possible to keep the weight of an ICF TK1 down to 8.3
: kg using 4mm Paulownia and one layer of 125 gsm (4oz) glass
: inside and out.

: The Paulownia for the deck weighed just 1.5 kg and the hull 2.5 kg,
: so unless you already have acquired a lot of cheap balsa, I'm
: not sure that the little bit of weight saving would be worth
: using balsa instead of Paulownia.

: Unless your carbon is lighter than 125 gsm, you won't actually save
: any weight over 125 gsm glass. It will still need roughly the
: same amount of resin to wet it out, won't it?

Hi Alan,

Thanks for the reply, I 'm sure it was your TK1 boat that first got the idea into my head actually.
A friend of mine sent me some pics of one built in nothern NSW ?
Yes your right about the amount of resin,and the Carbon I have would be at least 6 oz.
So therein lies my problem, hence the thought of using some balsa to save core weight.
I' ve also seen articles that indicate that core construction gets its strength fron the thickness of the core.
So I was thinking of using thicker Balsa probably 1/4, on the bottom and just up an inch or so one the sides ,then going back to the 1/8 paulowina for the rest of the sides and the deck.
I've made 1/4 inch thick Balsa cored rudders profiled to NACA foils then covered with one layer CF, with great success in strength and stiffness, thats where I got the idea for the balsa hull from.
I just replaced the alum rudder on my current glass TK1 with a Balsa/CF one.
The old alum (non profiled) one weighed 190 grams, the new profiled Balsa/CF one weighs 40 grams , and feels much more efficent in turning the boat during wash riding.

However , if yours came in at 8.3 using your system that will do me, it sound like an far easier build for the same result.

Its a beautfull boat too.

How is the stiffness of the hull and deck compared to a standard glass boat ?

Did you Vac / Bag ? , I've never had a go and dont really want to go to the hassle if I can achieve the weight doing a normal layup.

Regards

Bris paul