Hi Simon,

I believe you are looking at two different versions of the Type VII U-boat. Your first drawing (Top) is of a Uboottyp VII C (1944) General plan, and your second drawing (Lower) is of a Uboottyp VII B. It looks like they did move things around just a little. These prints are available in Eberhard Rossler's book Geschichte des deutschen U-Bootbaus, Band 1, published by Bernhard & Graefe Verlag. In addition, each builder during WWII may have changed things around as well.

I hope this Information helps...

Regards,
Don_