How about (2) 3 1/2" strips of that 3/4" guatambu plywood screwed and/or glued together. I used 2 pieces of 3/4" BC 7-ply Fir plywood and it made a great strongback. It was very stiff vertically; a little floppy horizontally, but that was cured once I had a sheer strip on either side of the forms.

Start building!!

Shawn

: I'm going to make my forms for my kayak tonight. I'll be using 3/4" 11
: ply guatambu plywood. I have some reservations about using a 2 x 4 for the
: strongback though. Framing lumber that we get in this area is really
: crummy. You can hand pick it in the lumber yard and it looks nice and
: straight. But after you take it in your shop and it continues drying, it
: can wind or curl considerably.

: I've considered laminating up a 2 x 4 beam out of kiln dried oak. And, I've
: looked at making the ladder type strongback as shown in Nick Schades book.

: I'd like to hear many opinions in order to assist me in making a choice.

: Thanks,

: John