There's nothing in US made plywood even close in quality to European made BS1088 Okuome. US ply comes in 1/8" (all interior grade) and 1/4" (too thick for most kayaks).
BS 1088 comes in 3mm,4mm,5mm,6mm. In order to carry the BS1088 designation it has to satisfy serious testing. It bends well, is a dream to finish bright and doesn't check. BS1088 is used to make ultralight and other homebuilt aircraft so it must offer something extra.
Taking on an adventure race in something made of 1/8" doorskins or cheap luan could make an adventure race even more of an adventure than you bargained for.
Charlie

: I am looking to build some boats. I eventually want to build a strip or
: stitch kayak. To start my boat building journey I would like to start off
: with a simple plywood canoe. This canoe is to be used to train for
: adventure racing and is to be a workhorse, not a trophy piece.

: I have seen what looks to be an easy project from B&B boat designs. Anyone
: have a better suggestion? My main question is it is hard to find Okoume
: here in New Orleans or anywhere close. What would be the drawbacks if I
: were to use fir marine grade plywood if my final plan is to glass and
: paint the final project?
: Thanks
: Jordan