In October, Kapitänleutnant Otto Dröscher took the SM U-20 on a long cruise, becoming the first German submariner to circumnavigate the British Isles. This successful mission proved that U-boats were capable of more extended operations than the Admiralty had previously appreciated, and the sinking of the first British merchant vessel that same month confirmed their utility as blockade ships.

In December, while the allied blockade was clamping down on Germany’s importation of food and raw materials, the U-20 took on an aggressive new master, Kapitänleutnant Walther Schweiger. Seen above, Schweiger is perfectly aware of the months-long administrative battle over ‘unrestricted’ U-boat warfare. He knows that the Kaiser will declare a blockade of Britain within days. But he is impatient, and he has had enough of the ‘cruiser rules’ — the laws of sea warfare which require him to give civilian ships warning, search them for contraband cargo, and let crews evacuate before sinking them with torpedoes.

These rules make countermeasures all too effective: the British Admiralty has advised vessels to steer straight at any submarines which surface to give that warning, thus forcing them to dive or else suffer a collision. Q-ships — armed decoy vessels built to entrap and destroy U-boats as they surface to stop and search what their captains think are helpless merchant ships — have already taken a toll on Schweiger’s service.

Today, Schweiger gives the allies a taste of what is to come as he and his crew sink three civilian boats in a single day near Le Havre on the northern coast of France. He is on his way to becoming the sixth most successful U-boat commander of the Great War — and one of the most hated.

At about 9AM, the six thousand ton SS Tokomaru is anchored and waiting for a pilot into Le Havre, her first destination after a long trip from New Zealand, when she is struck by a torpedo on her port side, flooding the stoke-hold and causing a heavy list. She sinks shortly thereafter about seven miles northwest of her destination, but her entire crew is rescued by the French minesweeper Saint Pierre.

In the late morning, sailors aboard the four thousand ton steamer Ikaria — also waiting for a pilot to deliver her cargo of coffee and sugar — spot a torpedo wake in the smooth sea, but the ship has no steam in her boilers, so the helm cannot avoid being hit. An explosion near the port side bow sends water rushing into the forward compartments, and she begins to sink forward into the sea as her crew abandons ship. Yet an hour later, the Ikaria is still afloat when a tug arrives, so the ship’s master and a few mariners re-board to bring their stricken ship into port. There, she is berthed along the Quai d’Escale for a day; port authorities decide to remove her to Avan Point and let her sink on the 2nd of February.

Finally, during the afternoon the Oriole, a 1,500-ton steamer on her way from London, is spotted as she passes south of Dungeness, but never arrives in port. None of the twenty-one crewmen is ever recovered; two lifebuoys wash up near Hastings on February 6th, while a bottle with the message “Oriole torpedoed – sinking” is recovered by Guernsey fishermen in March. The handwriting on the note is later confirmed by the widow of the ship’s carpenter. Only after the war will anyone confirm that the U-20 was responsible.

Submarines are already proving to be powerful weapons against military surface ships. The U-21, sister ship to Schweiger’s command, sank a much larger and more-expensive British cruiser in September. Based on a different design, the U-24 sank the pre-dreadnought battleship Formidable on January 1st. Because neither ship received any warning before being fired upon, these incidents have helped the most aggressive captains make their case in the ongoing policy battle over the ‘cruiser rules.’ Furthermore, a series of stinging defeats in recent surface actions have made the Kaiser even more risk-averse than before, elevating the importance of submarines as he seeks to get out from under the allied blockade that is strangling his factories and starving his people.

The sinkings raise an immediate cry of outrage from London, where Otto Dröscher is mistakenly identified as the culprit and denounced as a war criminal. In fact, Schweiger has hardly begun his infamous career.