Name three famous dates in Submarine History!

[Randomizer]

I'll bite.

22 September 1914. U-9 sinks armoured cruisers Aboukir, Hogue and Cressy off the Broad Fourteens. After this ships would no longer attempt to rescue survivors if a submarine attack was suspected.

1 January 1915. U-24 sinks battleship HMS Formidable off the Devon coast becoming the first British battleship sunk by a U-Boat. Events following the sinking contributed to the 1940 novel Lassie Come Home.

27 May 1915. U-21 commanded by KL Hersing torpedoes his second battleship, HMS Majestic off Gallipoli becoming the first U-Boat commander to sink two battleships. Two days earlier U-21 had sank the battleship HMS Swiftsure

Correction thanks to Neal, U-21's first battleship victim was Swiftsure's sister Triumph. My error.