@wittmann:
Just seen in Twitter: today, the 22nd September 1914 the U9 Sank three Cruisers: HMS Hogue, Aboukir and Cressy. All in about an hour. Remarkable feat.
The commander was Otto Weddigen. He first torpedoed HMS Aboukir, causing heavy flooding. It was evident she would sink. (Took 30 mins.) the British commander, Captain Drummond, ordered his two other Cruisers to pull alongside the foundering ship to aid in rescuing the crew, thinking it had hit a mine!
The rest had been made easy for the German commmander. Next Weddingen fired two torpedoes from 300 metres at HMS Hogue. The Sub had to surface, but was able to avoid destruction by the fast sinking second Cruiser (10 mins).
After firing two torpedoes at the last Cruiser, hitting with one, Weddingen turned his Sub around and fired his last torpedo at HMS Cressy, which took 15 mins to sink.
1459 sailors died, the rest were rescued by (Neutral)Dutch vessels and returned (illegally) to service.
Everyone British who could be, was blamed. From the Admiralty, the Admirals who were not present and who did not “lend” Desrtoyers,  to the commander of all 3 ships, Captain Drummond. Zigzagging at 12-13 knots as prescribed, was not done as the Cruisers could not maintain that speed!
The result was that Armoured Cruisers were never again asked to do the patrol and stopping major ships in dangerous seas was banned.
This U-Boat was a warship killer. She would later sink another RN Cruiser and a Russian Auxiliary Minesweeper. Her merchant GRT was low at 8,600 tons. This U-Boat would survive the war and the actions of September 22, 1914 will never get forgotten.