: I'm interested in building my next boat using a central aluminum rectangular
: tube. Any ideas for a source, and recommended size?

After pricing aluminum for a strongback on my current project, I retreated to steel. A 2"x2"x16' chunk of square steel tube with 3/16" wall thickness was $50 +/-. The best price I could find for sluminum was $4/lb., and anything suitably rigid would have been well over $100. Besides being cheaper, this tube is stout enough to hold up a house.

The mold blocks are 1"x1"x3/16" angle iron, bolted down with 2"x5/16" square U-bolts (sounds like an oxymoron, but that's what the hardware guys call 'em), so they're easily adjustable, easily scalable for different boats and/or station spacing, and stout enough to use for a ladder. I'll try to get a picture up soon.