: Scout leader with no money, lots of Styrofoam and cardboard... any
: ideas on how to build a durable cardboard kayaks. . .

Cardboard isn't durable because it is nearly impossible to get the corrugations covered with a waterproofing material. Plain paper is actually far better, and years ago paper canoes were sold. You are better off with newspapers saturated with an exterior varnish or paint. Build up 5 to 10 layers and you'll have a wood-fiber-reinforced plastic skin for your hull or deck. Google 'paper canoe'

The 'cardboard regattas' you might read about are rarely over 1/2 mile long, and many entries don't make it 100 yards.

If you are considering using cardboard because you need it for one of these contests then find a well ventilated space, and try saturating the cardboard with plastic resin dissolved in a solvent. Styrene dissolved in acetone might work. The solvents will probably be expensive, smelly, and an explosion hazard as they evaporate. Definitely nothing for scouts. And not safe for adults.

for 10 year old
: son and 280 lb man. Could the kayak for my son be a prototype
: for the big boat?

It could be but I wouldn't suggest it. Scaling down a big boat takes more time than downloading plans for a boat already designed for a kid. Check out www.yostwerks.com for free boat designs that will fit each of you.

Draw out the frames on your cardboard. Use these patterns to cut the frames out of your styrofoam. Use plywood for the center frames and use the foam between them for a floor.

Covering the frame with fabric and paint is inexpensive and durable. Or, get clear vinyl from walmart and show off the foam components inside the boat.

If you can carve those coolers into blocks that are a consistent size you can glue up a large slab. There is a special adhesive for styrofoam. Ask at your hardware store. I think it is called PL200. Carve this into a sit-on-top kayak. You'll need to cover this with fiberglass and epoxy resin to give it strength.

: I have seen the kayak plans for $40 online. I want a little better
: design; something like the S&G Guillemot, or am I
: dreaming??!!!

Tom Yost's plans are free. The website is above. Modifying them to work with styrofoam will be your challenge. Enjoy it.

PGJ