Josh,
Before you spend your hard earned money do some research about okoume. This topic has been chewed to death on this site but it's all worth knowing. You have to be able to talk the talk when dealing with a wood dealer.
If you do a search of the archives of this site for "okoume" or "BS 1088" or "luan" you'll get an idea of the vagueries of buying plywood for a boat.
Is the dealer selling "marine" okoume? Is it certified BS (British Standard) 1088 ot 6566? BS ply is the good stuff but is at the top of the price range. If you can afford it it will make your boat stronger, easier to build and finish.
You can't arbitrarily choose a ply thickness. When your dealing with ply this thin every millimeter counts. Build with what the designer specifies.
If you have the time, reading a S&G book like "The New kayak Shop" will take you thru' steps that will apply to any design you choose.
Good luck.
Charlie

: Thanks for all of the input so far, You have convinced me that okoume is the
: way to go....I found out that WoodPlanet in Chicago, IL can get okoume for
: me. They specify the thicknesses in english units though... and carry both
: 1/4" and 1/8" plywood. which I am assuming is comporable to 3mm
: and 6mm based on the conversion below.

: 3.000 millimetre [mm] equivalent to: 0.11811 inch [in]
: 4.000 millimetre [mm] equivalent to: 0.15748 inch [in]
: 6.000 millimetre [mm] equivalent to: 0.23622 inch [in]

: Can I get away using 3mm plywood when 4mm is called for? Will the strength of
: the finished product be inferior...will it be as rigid?

: 2 more questions.
: 1. Anyone have experience building the Chesapeake 17 from CLC ??? Any other
: comprable S&G boats I should consider??

: 2. I have been reading good things about buying epoxy from Raka.... is that
: the best choice for buying it online? (Price AND Quality). Does anyone
: know a Midwest supplier where I might be able to buy the epoxy. I live in
: the Chicago area but am willing to drive a little if the price is right.

: Thanks again.... I am going to be ordering plans this week, and most likely
: getting materials to get started with my Sept 1 paycheck.... I'm in the
: computer industry so I probably wont be able to resist putting up one of
: those build journal websites either!!!

: Josh