: To teach building I would need to do that in my shop.

Don't give up so easily. Plan on a 3 night deal and focus on the group building a skin on frame kayak. You'll need to do a lot of prep work, or get some help with it.
Assuming you use a Yost design and build in wood: Layout the patterns for the frames on individual pieces of plywood and give one to each participant, along with a cheap coping saw. It will take them about 20 minutes to each cut out one frame, or a stem. Have plenty of preripped stock for stringers. With 5 to 7 people working on each boat you have plenty of hands, and need fewer clamps. With one person at each end holding the stringers to the stems in approximately the right place you can set in the forms and attach them temporarily with brads or screws. Once the stringers are marked, everyone gets to trim one to size and screw it on. Everyone stays busy sanding ! Probably takes twoo weeks to build this far. Goes faster if you have the parts already cut, and substitute your parts where necessary. Time permitting, let them apply a water-based finish to the wood. Next week the hull gets skinned with clear vinyl and a cockpit and floor goes in. Three evenings, one boat. Raffle it off as a door prize if you want. Too many participants? Bring materials so they can make Greenland paddles.

Allow for time to sweep up sawdust. Talk less--they don't need lectures. Let the participants participate more. They'll love it, and if you need an extra week to finish, they'll probably go for it.

Enjoy. E-mail me if you need help.

PGJ