U-boats on the Southampton–Le Havre route

On the afternoon of 13 October 1914 the British Torpedo Boat No. 116 of the Portsmouth local defence flotilla sighted a German submarine off the eastern tip of the Isle of Wight, near Culver Cliff. A British chronicle of the events of the war recorded this as the first appearance of a German submarine on the route from Southampton to Le Havre. Southampton was the main port from which troop and supply transports sailed for France, and Le Havre was just becoming the main British base on the Continent again.

The submarine was little more than a kilometre from the torpedo boat. The British made for it at full speed and opened fire, but the U-boat managed to dive. According to the British official history of the war at sea, it was a matter of a few seconds that prevented it from being rammed. That same day the French reported a submarine near Cherbourg, and a day or two earlier another off Cape Gris-Nez. Even before this, fearing German submarines, the British had mined part of the sea off the Belgian coast to protect the routes across the Channel.

The convoy changes course

The appearance of a U-boat in this spot came at the worst possible moment. A great convoy carrying the first Canadian contingent was just approaching England: some 30 transports with more than 30,000 soldiers. The Admiralty had from the start preferred to send it to a port in the west of England, but the War Office pressed for Southampton, where everything had been prepared for unloading and moving the troops by rail to Salisbury Plain. On 10 October it was finally settled that the convoy would put in at Southampton.

The incident off the Isle of Wight decided the matter. According to the British historian Julian Corbett, within an hour the Admiralty decided that the safety of the convoy outweighed all military considerations. On the evening of 13 October Admiral Rosslyn Wemyss, commanding the escort, received orders to direct the ships to Plymouth. Soon afterwards, for the same reason, two other troop convoys returning home from Egypt and India were diverted to Liverpool.

Hunting the convoy

The British fears were justified. According to later British findings, the German command learned from its agents in New York that the convoy had sailed from Canada and believed it was heading for Boulogne. On 10 October two submarines, U-8 and U-20, were sent into the Channel with orders to attack the transports. Neither of them, however, got as far west as Plymouth, and the Canadians arrived safely.

As Corbett stressed, despite the bold offensive of German submarines in the waters around the British Isles, not a single troop transport suffered at the time. The presence of U-boats nevertheless forced the British to change routes, strengthen patrols and suspend sailings, which complicated the movement of men and supplies to France.