: Looking to build a new strongback that will be used over and over. . . .

Long before builders used strongbacks they built boats in lofts that had wood floors. "Lofting" meant drawing the boat's lines on the floor, and frames were nailed in place. Right to the floor.

So make a section of 'floor' 18 to 24 inches wide and as long as you need. Then put that on sawhorses to get it up to a height where you can work comfortably.

Basic ladder-type strongback is a pair of long 2 x 10s or 2 x 12s with short 2 x 4 pieces going across them like rungs on a ladder. If your plans call for spacing the forms a foot apart then the rungs are a foot apart. Canoes and SOF kayaks space forms further apart so use fewer crosspieces

Not sure where the frames will be spaced on future boats? Plywood or OSB can be used for a solid top instead of the 2x4 crosspieces.

Lighter boats can be built on lighter strongbacks so go with 2x8s, 2x6s, or even use 1x stock or a single 2x4.

I'm going with a pair of tables framed with 2x4s and topped with 1/2 inch OSB. Each table is 8 feet long and I can bolt 2 end to end.

Keep it cheap and simple on the strongback. Even the worst one can be shimmed and tweeked to get it to work. Worstcase scenario is you clear and level a patch of land and build on the ground like the original builders of these boats did. I bet they had sore backs when they were finished :)

Have fun with whatever design you go with.

PGJ