[Public-List] Making new Hatch

[Bobby]

Hey Yall,
 
I've made a new sliding hatch cover for my companionway.  I basically copied the design of the original which is essentially 1/2 Teak Plywood curved and attached to pieces of teak.  I've created some ribs mirroring the shape of the curve and bent the plywood to that shape and clamped it down.  
 
My question is how do I make the plywood keep the shape of the curve?  The front part of the plywood sits in a routed piece of teak and the back stopper is a curved piece of teak.  When it's all together it doesn't hold the shape enough to sit in the track.  
 
Any thoughts would be most appreciated.    
 
Thanks,
Bobby
s/v Caprice #388