Depth charge attack in BF 13, 120m deep, year was 1939!
Conning tower destroyed, flak and deck guns too. Severe flooding. Port side diesel, electric motor and propeller out of action. Radio, sonar and fore batteries beyond repair. No working torpedotubes. 3 dead one wounded.
Had sail around British Isles to reach Kiel. Actually docked in Helgoland. No watch crew on deck
Similar damage from mines to type II have occurred.