: I am building my first kayak. I've made my forms and am ready to build the
: strongback. I am interested in Nick Schade's box beam design. It seems
: simpler than the ladder type alternative and I agree with him that the
: boat itself will lend strength and stability to the strongback. What are
: the hidden risks of the various designs? Should I be worring about this at
: all?

No, you should ntobe worried about this.

The greatest "hidden risk" is in using the wrong tool for the job at hand. I can tell you from experience that it is possible to drive nails with tools other than a hammer, and don't assume I am condemning the use of tools for purposes other than they were originally intended. I merely want to make the point that each boat design, from birchbark canoe to ocean liner uses fixtures, jigs, supports and framing which are unique to that particular design. Sure, you can adapt ANY base into a suitable structure for supporting the pieces as you put together these watercraft, however, there is always going to be a support system ( and let me use that term as a general term for all types of "strongbacks") which is simpler than the rest, or cheaper than the rest, or faster to assemble than the rest. For example: A birchbark canoe starts with sticks tapped into a smooth area of dirt, and a Walrus kayak, built from George Putz's book starts from a wood floor.

Some boats do not need strongbacks at all. With others The forms may be designed so that they attach to a specific type of structure. If you are building a boat from your owun designs you will probably need to figure out your own method of holding them in place. There are several existing ideas which can be adapted, so you would take your choice. If, on the other hand, you are building from someone else's plans or designs, then it would be wisest to go with the ideas of the designer. If they have done their work well then they will have considered the best support structure for the forms and they have advised you on how to make it.

So, the short answer, at long last, is go with what the designer says. If they say "box beam", use a box beam. If they say "2x4" use a 2x4, and if they say "Ladder-type strongback" then you go with that.

Canoes are traditionally strip built from ladder type strongbacks, with each crosspiece of the "ladder" set at the distance for each form. They are built upside down, and the forms are attached so they protrude through what will become the open top of the canoe. Kayaks hulls may be built this way, too, but when it comes time to make the deck you start to have choices, and potential problems. You could set up a new set of forms on the ladder back for the deck and build it upright while the hull is set aside. Or you can build a second strongback and hope you have all the forms spaced EXACTLY in the same places as the first strongback.

Or, you can use single-piece forms and have a support running through them. With this system you strip the hull, then flip the whole thing over and strip the deck -- hopefully leaving an unglued seam around the curcumference so you can separate the top and bottom to glass the insides before re assembling them.

So, if yor plans call fro a box beam, make one and use it in good health. and if the next boat needs something else, build it at that time.

hope this helps

Paul G. Jacobson