If you go back into the archives of this site you will find various proposals for using bamboo. Complete bamboo SOFs even bamboo strippers. Even tho' this stuff comes up year after year it hasn't gone anywhere. The big things are all those bumps sticking up and it's overall character which makes it hard to work with. It tends to split, doesn't take metal fasteners, doesn't yeald to edged tools too well and there are suspicion it rots and doesn't glue well.
If this is your first boat don't weigh yourself down trying to go where nobody else has gone. It will just postpone getting on the water.
FWIW we have already determined that PVC pipe doesn't work and fiberglass tent poles is kind of dodgey too.

: Hi there,
: I've been thinking about using bamboo for the gunwales on my first
: skin on frame kayak.
: It should be a bit heavier than pine (gunwales will increase around
: 5lb ) but more flexible and tough.
: The point is I can find only small pieces (floor's bamboo) so I
: should join 4 pieces each gunwale. Is it so bad?

: And what do you all think is better between vertical or horizontal
: laminated bamboo for gunwales?