[REL-UBM]Kriegsmarine AOB Finder

[Hitman]

Edit - i did not realize the first time that you were speaking of U-boat's and not Fleetboats

Anyway the US subs had :

FOV was 32° and 8° not 38 and 9 - fleet type submarine manual pages 77, 443 and 526.

Thats a liner field of view of 419,44 feet pr. 1000 yards in high power (8° or x6 zoom) or 1677,76 feet in low power (32° or x1.5)

Apparently, there were more differences between US and german technology before WW1, but then the US submarine branch got much influenced by the superb technology they found in the surrended german U-Boats. Argonaut/Narwhal/Nautilus are a very close recreation of the WW1 german U-cruisers f.e. and in optics they also seem to have followed a lot of german ideas. Certainly, the double image stadimeter is a genuine US creation (Lt. Fiske, 1895) but the germans adopted it quickly and also used it for the AOB measuring. But other than that, the similarities are enormous, the US subs using however outdated WW1 german technology by 1942 in optics (No fixed heigth of eye periscope, no TBT/UZO until late 1943, etc.) , yet what they lost in that area they more than compensated in electronics (Radar and TDC mainly).