Sit-on Kayak out of Foam?

I am new to the forum so pelase forgive me if I am posting a common question. I need a small light boat to be able to carry. I was thinking about taking foam sheets, bonding them together (making a block 2' x 3' x 8'), then using a grinder to carve out the shape and covering it with fiberglass. I want a sit on type of kayak. Does anyone think this would be a decent idea? Suggestions? It will mainly be used for small lakes and ponds. No fast water.

 

The concept is possible but to get something strong enough and puncture resistent enough, you might end up with something heavier than a comparable plastic one.

And 8' is an awefully short kayak!

There are alternatives if you want to build your own Sit On Top.

 

Sit on Kayak cnostruction options?

What options are out there, in terms of construction method, for sit on kayaks?

 

Wooden. E-mail me if you want the link to existing plans. Another version in the works too.

 

Sit-on-kayak = surfboard

Otter,

So basically you want a surfing board with a seat? That's been done before! So. now you know it's possible! Most one person kayaks are portable by one person, so is a surfing board. You can make the bottom out of high density foam covered in glass and
don't worry about puncturing, as long as you're not going done any rough-ride-rivers you'll be fine, lot's of people go kayaking with full glass crafts and nothing happens.

BTW JEM, I think the whole structure will be heavier using wood, unless you go building ultra light.

 

The one I built out of wood and fiberglass, 15'6 x 31", came in at 60 pounds. Much lighter than the plastic ones of similar size. Very durable. (I sell canoe and kayak plans but don't want to link here and take advantage of a free and open forum.)

I know what the websites like Wildy and OC claim theirs weigh, but it just ain't so! I rented and borrowed a few of them. They all weighed about 7-10 pounds more than they claimed on the websites.

 

I have a 16.5 foot cedar-strip canoe that weighs in around 70lbs. So your specified weight is quite likely. The only thing I would question is the use of fiberglass ... I use epoxy much stronger and lighter, plus it sticks to the wood much better too. would like to see your kayak/canoe designs ........ is there a link to a website?

 

http://www.jemwatercraft.com

 

Always nice to build your own. You could also try and find an old beater that someone is tired of and fix it up " cheap". Canoes and kayaks take up a fair amount of space so when they aren't being used folks tend to want to unload them. Keep your eyes open.

 

I know this is a very old thread, but I wanted to share my 12' foam kayak, the measurements and instructions are free on the Instructables website if you search for "Sawfish"
the boat is made of 2" EPS foam and coated with a finish I call "poor man's fiberglass" the finished boat weighs 23 lbs, is stable enough for me to stand up in and paddle (28" wide), and strong enough to support my 180 lbs with only the ends of the hull sitting on saw horses.

 

http://www.duckworksmagazine.com/ has had a few articles about simple foam kayaks. Dave Lucas has been making them. Look back at the last couple of months and you should be able to find the articles.

He used foam from the lumber yard, carved to shape and then glassed. Build one in a weekend.
C.O.