
Some Experimental Boats made from Coroplast and other Corrugated Plastic sheets.
Because Coroplast is quite an inexpensive material, it's easy to experiment with it. Give it a try, start with cardboard models and go on to a 4x8 sheet.
Ken Simpson has 2 Coroplast Boats

Ken's fertile imagination has also produced a coroplast/plywood composite cruiser boat.
More details on the Take apart Cruiser
Andrzej ''kooniu'' Jasztal made one of Ken simpson's models Here is a link to the article from Duckworks
Paul Elkins has several Coroplast Boats.
Applied Sciences has free plan for "45 Minute Kayak"

Link to pdf plan of an 8 ft corrugated plastic kayak. This is likely a fun inexpensive afternoon project with the kids. Minimum instructions. I would use Gorilla Tape or the Scotch heavy duty tapes for this and make sure I have a pfd on. Make a model out of cardboard first.
Too short to be an adult's boat but will easily carry a smaller human.
Oru Kayak
The Oru Kayak is an elegant 12 foot Kayak which folds into a package small enough to bring on a plane. This is a portable boat light enough to be practical. Can be unfolded thousands of times.

Corogami Dragonfly Kayak
Folding Boats with No Parts coroplast boats is stiff and easy to assemble.

No Parts have designed a model of folding boat that is hugely simple to fold up and transport. I think they are designing it as an emergency/rescue boat. I don't think it is available commercially. They are using thicker coroplast. Looks like close to half inch, this makes the sheet much stiffer.
Tucktec
I'm cheating a bit because this is not corplast at all but it is rather a good folding boat. It has the advantage of being stiffer. It looks a bit like polycarbonate but stronger. At one point he hammers it and the boat survives. Have a look.
Tucktec folding boat It looks like you can buy it directly from them and it is also available from Amazon.com.
Tucktec Foldable Kayak, Canoe from Amazon.Coroplast for Remote Control Boats and Aircrafts
Coroplast is widely used as a material for remote control miniature boats and planes. Here is a link to a Jet Boat and another link to a Jet plane
If you are interested in RC airplanes here is an introduction to building RC planes book for you. from Amazon
Coroplast

Flotation
email me : Christine
Corrugated Plastic Sheet Links
My Coroplast page includes links to manufacturers and where to purchase corrugated platic sheets.Folding and Take Apart Boats
Ultra light boat building
Skin on Frame Boats such as Kayaks are very light
Dories Traditional boats of the fishing grounds
Punt Boats

As simple as it gets. A coroplast sheet with the sides folded up make a quick boat. Rainbow Family Gathering made these boats.
Some relevant amazon.com links. It helps pay for the website.
Heat gun helps make good bends by softening the plastic.I used a screen rolling tool to crease the plastic after heating it: Prime-Line P 7505 Screen Rolling Tool with Wood Handle and Steel Wheels
Gorilla 6003001 Tough & Wide Duct Tape, 2.88-Inch x 30-Yards
Tucktec Foldable Kayak, Canoe from Amazon.
Shoreline Marine Propel Escaper Kayak Paddle, Black/Red, 230cm
I have this camera and I find it really works quite well. Lousy instructions but there are quite a lot of videos on youtube so for me a good buy. APEMAN Action Camera 4K Wi-Fi Waterproof Underwater Camera Ultra Full HD Sport Cam 30M Diving with 2" LCD 170°Wide-angle/2.4G Remote Control/2 Rechargeable Batteries/20 Accessories Kits
Always wear a life jacket, eventually you will like to have a nice comfortable one.
Onyx Outdoor Movevent Torsion Vest-Red XS/SM
Utility Knife - Heavy Duty Folding Box Cutter, Quick Change Blades, Lock-Back Design, Aluminum Anti-slip Handle with Belt Clip, Pocket-sized, 7 Double-sided Blades Included by E-PRANCE, Orange
Used with washers, a riveting gun can be used to put coroplast pieces together: TEKTON 6555 Rivet Gun with 40-Piece Rivets
Small Print
This information is for general knowledge. Using non tested materials can be dangerous. If you build a coroplast boat be careful and make sure you test and use your boat in safe waters with appropriate personal flotation devices and backup help.
Coroplast
Coroplast is a trade name for Corrugated plastic sheet made in many colours and thicknesses. Coroplast is a US company. In other parts of the world other trade names might be better known. Examples are Plaskolite, Corplast, Coroboard, Corruboard, Polyflute, Intepro, Correx, Twinplast, Impraboard, Alylux are other tradenames. If you are looking for a local supplier Googling these alternatives might be helpful.
I have not personally tested these boats. I can't say if they are safe. These are experiments by people who like to play and design things. Be careful already!