: allready made a wooden kajak ( glassfiber and epoxy)

: Last summer we made a week in Poland ( 5 days camping and trekking)
: Unluckily we had many portages over fallen trees and I saw the damage ( I can
: fix it well)but I would use the canoe in semi white water , rocks and so
: on.

: At this moment I was just curious if I could build a canoe totally whitout
: glass and epoxy !

: Or beneath the waterline in plastic ( a little flex tolerated) and the upper
: part
: wood ......or
: Maybe beneath the waterline kind of canvas (pvc maybe a la Tom Yost) but it
: tears rather easily in sharp surrounding.......or
: Build in wooden strips and beneath the waterline thinner strips with plastics
: strokes glued on .......or
: Just strip building complete and beneath strokes of plasic (rubber) every 10
: cm

: You see: still fooling around with some ideas .. and still curious at others!

: Anyway , apologize for my bad english ( I' m from Flanders (Belgium) )

: Everybody , thank you allready for your input
: gr
: jos

The problem ends up being weight of the boat vs. strength. With wood/epoxy/glass it's not hard to make it strong enough, it is very tricky making it strong enough and keeping it light enough to be easy to carry. Squirt boats, longish extreme design whitewater kayaks, are still made of glass/epoxy and are very strong, but are built in molds (so no core needed) and are generally around 18-25 layers of 6 ounce glass fabric. Poly whitewater boats are heavy, fairly strong and damage resistant, also require a huge expense in tooling, not something you can reasonably do at home.

You might be able to find Royalite (think that's the right trade name) it's an ABS sheet with a foamed core all in one, it's heat moldable and might be a reasonable strip material. It's not inexpensive and is quite heavy compared to wood for strips. Most of the engineering plastics that aren't cored are fairly heavy for their strength, that's the advantage of wood, it's fairly light for it's strength.

Another possibility is building the boat from strips of Airex foam as a core. This foam is somewhat flexible and quite strong compared to other foams and is fairly damage resistant. Downside, as per usual, is the cost. The suppliers generally only sell by the box which will be enough foam for several kayaks, it's fairly pricy even per sheet let alone per the box price.

Bill H.