More info/pictures from the last build:
http://clearstreamwood.com/WordPress/?p=9

Dan

The strongback is also similar to what Bjorn uses. He makes his out of long 4/4 stock. I didn’t have any nice boards that long so I laminated some strips of 1/2″ fir plywood with glue and 7/8″ staples. You bring the ends toegther and it ends up having a shape similar to a kayak. It’s a bit easier to work on the boat. The 2×4 you see is my old 1/2″ plywood boxbeam internal strongback that I normally use. There’s no room for an internal SB in the BP. The decks are too low. I found the external SB a bit floppy so I attached it to the internal one with a few screws. The combination is a light, rugged, dead-flat strongback. I like it. If I ever need my internal one I just need to remove a few screws.

Dan

So, essentially, you’re just setting up all the cross section forms and skipping a plywood stem form. I imagine that this could be used in any type of kayak build.

Is the strongback simply mounted on a 2×4 or is that a boxbeam of some type?

Check out the post from the last build:
http://clearstreamwood.com/WordPress/?p=13.
Click on the image for a bigger version. The same pic is in the gallery:
http://clearstreamwood.com/WordPress/wp-gallery2.php?g2_itemId=148&g2_page=9

“… I ripped a piece of 4/4 western red cedar in half (about 3/8″ thick), cut them to shape and hotglued them onto the forms and strongbacks. Small plywood spacers were used to raise the stems to the correct position (scaled off the plans). The stems were beveled for the strips with a block plane.”

I got the rough shape by simply scaling it off of the plans. The tips are held in little cradlea made of scrap wood/plywood screwed to the strongback to keep the tip in alignment and to elevate them to the correct height above the strongback. Daps of hotglue are used to attach it to the other forms. It’s worked well on both BP’s built so far. The stems could have been made out of a hardwood or marine plywood.

Hope I explained it well enough,

Dan