Geoff,
I think you're talking about JD's technique that was detailed by Paul Goodwin here:
http://cerebus.winsite.com/laser/DNboard/mesgConst/973.htmlWhile at the Minnesota Challenge (Fall Tune-up, Western Challenge, JD Invitational, whatever it was called ...) I learned a new trick for bonding cracks in side panels. I wish I had witnessed it first hand, but I have a good description of the event. JD demonstrated this new technique to the wonderment of the Detroit sailors who were witnesses. Start by folding up some paper towels and lay them along the inside of the crack. Cover the paper towels with a strip of clear plastic and tape the plastic to the inside of the hull. Put a small slit in the plastic and tape a shop-vac hose over the slit. Turn the hull so the crack is level, and preheat the hull in the repair area. Mix up some epoxy, turn on the shop-vac, and lay a bead of epoxy along the crack. The vac will draw the epoxy into the crack, so keep applying epoxy on the outside until you see it coming through and soaking into the paper towel on the inside. Once the crack is completely filled, turn off the vac and align/clamp the hullside. Voila!!! This easiest, most effective method for repairing a hullside crack I've heard of.
Tom