hms submarine conceived designed commerce royal_navy time launching largest submarine world idea submarine cruiser proposed early practice based german class ton cruisers laid november naval dockyard chatham completed september commissioning december washington naval treaty britain ban submarines ban use merchant ships purpose armament designed successfully engage classes vessels likely escorting convoys destroyers frigates certain secrecy surrounded government going lengths taking national newspaper court pictures new submarine following launch copies paper seized description inch thick pressure hull feet inches diameter amidships divided water tight compartments completely surrounded external hull contained main ballast tanks fuel intended maximum diving depth feet reduced feet service expected sink targets gunfire given inch guns able defeat destroyer armed merchant ship fitted bow tubes inch torpedoes supplement guns armament carried inch guns twin turrets forward aft conning tower range yards circular trunk ran mounting magazine pressure hull contained rounds gun working chamber feet diameter encircled trunk pressure hull gun mount ammunition problematic sustain desired rate fire rounds gun minute special ballast tanks compensate loss weight ammunition fired working control guns required men fire control tower middle conning tower section raised feet use upper control room tower pressure hull aft control room room foot rangefinder bridge raised feet torpedo tubes came cancelled class submarine provided tube took minutes space torpedo room restricted propulsion main engines cylinder admiralty diesel engines total output horsepower auxiliary horsepower man diesel engines taken installed battery charging purposes underwater propulsion electric motors horsepower fitted hoped achieve horsepower electric motors highest power achieved power trial march horsepower groups batteries cells weighing total long tons batteries fitted water filled cooling tubes jackets pumps heat recorded use battery cooling reduce core temperatures aggressive charge discharge cycles theory knots surface economical speed greater range normal cruisers sets diesel engines suffered continual mechanical problems reduced speed range average diving time depth minutes seconds handling underwater considered superior submarines period career commissioned december accepted april voyage gibraltar main engine drive wheels found damaged repairs sent mediterranean_sea starboard broke power run january new set gears needed malta port broke place april commanding officer reported internal arrangements satisfactory auxiliary machinery accommodation cramped ventilation poor ship suffers humidity diving arrangements good main auxiliary engines troublesome spent time repair laid placed reserve finally scrapped december
HMS X1