german type submarine boat german_imperial_navy german kaiserliche_marine world war disappeared patrol class lost ordered october laid shipyard kiel november little metres length displaced metric tons long tons depending surfaced submerged carried torpedoes bow torpedo tubes armed deck mounted machine gun launched commissioned march broken sections shipped rail austro hungarian port april officially joined flotilla departed patrol temporary duty turkey seen postwar german study concluded likely victim unexplained technical problem absence minefields enemy action design construction german_army rapid advance north_sea coast earliest stages world war german_imperial_navy found suitable submarines operated narrow shallow environment flanders project design effort begun mid august produced type design small submarine shipped rail port operations quickly assembled constrained railroad size limitations design called boat metres long displacing metric tons long tons torpedo tubes initial submarines numbered ordered october shy months planning class began laid november launched march built feet inches long metres draft metres single brake horsepower cylinder diesel engine surface travel single shaft horsepower electric motor underwater travel attached single propeller shaft speeds knots mph surfaced knots mph submerged moderate speeds sail nautical miles surface nautical miles submerged batteries like boats class rated diving depth metres completely seconds armed centimeter torpedoes bow torpedo tubes outfitted single millimeter machine gun deck complement consisted officer thirteen enlisted men service career submarine commissioned german_imperial_navy march command year old time boat underwent trials german home waters boats selected mediterranean duty rail shipment process shipping boat involved breaking submarine essentially knock kit boat broken approximately pieces loaded railway shipped port site ally austria hungary main naval base april parts arrived took weeks assemble joined german late way adriatic austro hungarian port base boats flotilla actually operated patrol loaded ammunition turkish forces turkey limited range towed light cruiser sms austro hungarian navy cast near island planned route south north went arrived half fuel left germans received radio message nautical miles unable completely understand trace found boats lost war postwar german study concluded loss probably result unexplained technical problem minefields route record attacks boats area british records sources based demise north_sea april authors assert actually fate point gone missing nearly year supposed sinking north_sea
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