german type submarine boat german_imperial_navy german kaiserliche_marine world war disappeared black_sea september ordered october laid shipyard bremen november little metres length displaced tonnes long tons depending surfaced submerged carried torpedoes bow torpedo tubes armed deck mounted machine gun originally pair boats sent replace austrian pair sent dardanelles broken sections shipped rail march launched april commissioned german_imperial_navy austrians opted agreement briefly commissioning spent majority career patrolling black_sea constantinople flotilla boat sank ship grt september october helped repel russian bombardment bulgaria considered transfer disappeared late september transfer place fate officially unknown sources report struck sunk russian airplane design construction german_army rapid advance north_sea coast earliest stages world war german_imperial_navy found suitable submarines operated narrow shallow seas 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 tonnes long tons torpedo tubes initial submarines numbered ordered october shy months planning class began laid kiel november built metres 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 standard complement consisted officer thirteen enlisted men construction neared completion early march turkish leaders pleading german austro hungarian allies send submarines dardanelles help attack british french fleet pounding turkish positions germans induced austro hungarian navy german und send boats built boats promise replacements work complete yard rail shipment process shipping boat involved breaking submarine essentially knock kit boat broken approximately pieces loaded railway boats ready shipment main austrian naval base march despite fact austrian pair ready german engineers technicians accompanied german boats worked supervision head newly created boat special command german typically assembly process took weeks accordingly launched april career trials developed leak took time repair meantime assigned austrian number austrian commander german crew intent transferred wore civilian clothes austrian uniforms time dragged austrian ready eventually admiral head commitment overt hostility neighbor ally italy change heart austrians germany resolved retain send aid turks completion leak repairs boat commissioned german_imperial_navy command year old native commissioning boat temporarily joined flotilla german limited range able entire journey turkey night towed austrian destroyer june reached having success journey joined german der division ineffective hampered limited torpedo supply weak engines negotiating strong dardanelles currents nearly impossible sent patrol black_sea july cruising success 5th 22nd september sent bulgaria patrol russian black_sea coast september torpedoed sank british steamer nautical miles cargo ship gross register tons grt ship credited sunk constantinople flotilla month bulgaria joined central powers battleships aircraft seaplane carriers began attacks bulgarian coast october based time sortied disrupt bombardment 27th got position fire torpedo russian battleship known crew heard thought torpedo explode hit despite lack success attempt cause russians break attacks withdraw early cruising black_sea germans good luck black_sea priority saw value submarines russian attacks began negotiations purchase bulgarian sailors practiced pair boats technicians sent kiel training german submarine school transfer took place reasons sources remained german flag july germans sent sms attempt russian response command taken returned germany command new stationed attack ships sailed response mission unfortunately russian spotted bombed boat preventing goal submarine way rear admiral sortied dreadnought cruiser destroyers russian fleet engaged forced mission retire sources quiet damage suffered summary raiding history fate september departed operations heard according sources mined black_sea june russian pilot captured germans reported russian airplane bombed sank october position near authors dwight dubious claim fate officially unknown men lost senior radio officer bulgarian lost war
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