I am no expert, and haven't done any bending yet, but I was planning to use the cheap & easy method described in Kayakcraft. It involves a piece of plastic pipe (PVC or ABS) as the steam "box", sized according to whatever you're putting in it, and a simple kettle for steam source. Stuff rags around the mouth of the kettle and the other end of the pipe to keep the steam in.

Don't know yet how well this will work, but it sounds reasonable. Good Luck.

: I am about to build a folding sailboat, a bit like an umiak, that'll have an
: ash structure. Ash bends indeed but I'll have to steam some 12 by 20 mm
: stringers. I tried to steam such spars by holding them over a boiling pan
: and made a fool of myself!
: I kept them hours in the water instead with a pulling cord tied at both ends,
: but this gives the stringers a boomerang shape as they'll rather fold in
: the middle, not in an even fashion. A carpenter told me to use several
: cords, but that seems quite unpractical.
: Would there be a way for an amateur to steam wood without a sophisticated
: equipment?

: Regards