I have been trying to find an answer to this question for years. So far I can't find clear photos of U-47 showing a centrally located ventilation duct as depicted in the Amati kit. It appears from the newsreel films and photographs that I have seen that the Amati kit is not correct for U-47. It is correct for some type VIIB's, but certainly not all. I believe that all of the VIIB's were originally designed and constructed without any external type of ventilation duct. These ducts were retrofitted in the field based on war patrol experience in the very early days of the war. The retrofit seems to have taken two, perhaps three configurations. (1) Central positon, behind the scope housing. (2) External trunk on one side of tower, and maybe (3) External trunks on both sides of tower. Configurations #1 and #2 are confirmed in many photos, #3 is my guess based on some blurry photos. At the time of the Scapa Flow raid U-47 did not have an external duct, based on several photos. She MAY have had a central duct at this time, but I don't think so. My guess is that she went on this war patrol in her originally designed configuration which featured flush ventilation holes on the afterpart of the tower below the wintergarden, but no central duct. My reasons for this are that the raid took place very early in the war - Oct. 39 - before the retrofits took place, and also the absence of any clear photos even hinting at the central duct. This central duct may have been added later in the war to U-47, but again there is no evidence of this being done. Basically, I think Amati based their kit on photos or drawings of type VIIB's that had the retrofitted central duct and then got it wrong by labeling the kit as U-47. It is a great kit and makes into a superb model, but it is probably more historically accurate to model one of the other Type VIIB's very early in the war or even pre war rather than U-47 at Scapa Flow. The kit can't be used to model a VIIB beyond the very early part of the war because the wintergarden is tapered and narrow rather than the circular retrofits that were added as the war progressed. I don't know exactly when the Type VIIB wintergardens changed, but it would probably be in late 1939 or very early 1940. Anyway, the Amati kit can be used to accurately depict a pre-war Type VIIB with very little modification. There are some great photos of pre war VIIB's that can be used as reference.