What do you mean by "wooden deck"?. All type VII U-boats had wooden decks. In early war the decks were more complex. In late war they build also wooden decks on these boats but more simplyfied, resulting in less wood used and less labour spend. Only the bow and stern had sheet plating sections. This was the same with the type IX.
SC-member: 2104.Momentarely trying to construct U-123 and U-805 with "Schnelltauchback", BASED UPON the SCALESHIPYARD hull of U-505