Night Heron Build Question

Hello everyone,

I recieved the plans for my night heron yesterday and began cutting and pasting the form outlines on mdf.  I notice that the form which runs parallel to the boat and holds forms 1,2 and the internal stem is missing from  the plans.  Am i missing this page or should i be drawing up this piece on my own?  Or am i completely missing the point and need a little guidance?

Thanks!

Correction :  Its a night heron hybrid if that changes any answers.