Bob 'Ootek' Warren build a pretty nice roof rack using Unistrut for longitudinal and crossbars, carriage bolts, and Quik-n-easy clamps for the raingutters on his Suburban. Quite beefy, yet lightweight.

Your friendly local electrical supply or plumbing supply house would have longer lengths available than HD. If you know an electrician or plumbing contractor, you could probably have them buy it at their discount.

For a strongback, you could always mix wood and steel--use unistrut for the strongback, and carriage bolts to 2x2's to which the forms are screwed.

Shawn

: Hope Ken doesn't mind me butting in, but I've messed around with the stuff
: for mobile bases for my jointer and planer. It would probably work for a
: strongback, but you'd have to join two sections together. The Home Depot
: by the house has 10' lengths under the name Uni-strut. I don't know if it
: can be purchased in longer pieces. Also, the fittings sold at HD are
: relatively expensive. I'd estimate at least $60-80 plus bolts, nuts and
: washers for a strongback setup based on my HD's prices. Another potentia
: problem is the weight. It would be heavier than a 2x4 and maybe heavier
: than plywood. Not sure though. It's a good idea for multiple boats.

: Kurt