John, I really like this method. I'm planning on doing it for the next boat. The 2x2x20 square steel beam will cost about $22.

What did you pay for the u-bolts and nuts?

The pine 2x4 I used for the internal strongback on my Guillemot has since warped beyond usability in the 8 months since I finished.

One concern is that the setup would be very top-heavy. I imagine you anchored the beam to your sawhorses with another u-bolt.

: I think Ray has it right - the classic external is a hassle to store, even if
: you make it in shorter lengths sleeved together.

: I went with the external to make the instructions easier to follow BUT used a
: length of 2" x 2" x 1.25" square steel tube. The uprights
: are held in place with square "U" bolts which makes it easy to
: disassemble or change the spacing. Once I get my hull glassed (any day
: now...), the steel will get mounted on the wall near the ceiling, and the
: remaining pieces will go in a box in a cabinet.

: I think I've got the best of both worlds.