Sinking of the Swedish steamer Hanna

During the night of 12–13 March 1915 in the North Sea, a few miles north of Flamborough Head, a powerful explosion tore open the bow of the Swedish steamer Hanna. The ship sank within half an hour and six sailors were killed. The British Admiralty concluded that Hanna had been torpedoed without warning, and the British chronology of the war calls her the first neutral ship sunk by a German submarine. To this day, however, it is not certain that this was a U-boat attack.

Coal for the Canary Islands

Hanna was carrying a cargo of coal from the mouth of the Tyne, from South Shields, to Las Palmas. She put to sea on the afternoon of 12 March together with another Swedish steamer, August Leffler. Sweden was a neutral state, and its ships were still sailing to British ports at this time, although since 18 February the waters around the British Isles had been a German war zone.

According to British and local accounts the explosion occurred shortly after midnight, according to various accounts between half past midnight and two in the morning of 13 March, between Scarborough and Flamborough Head. The blast destroyed the forward part of the ship. Six of the eight sailors asleep in the crew’s quarters in the bow were killed: the boatswain, four stokers and the steward. The others took to the boats. They were rescued by the crew of August Leffler, who then transferred them to a Norwegian ship, which landed the survivors at Hull.

Torpedo or mine?

Hanna’s second officer reported that just before the explosion he had seen the track of a torpedo on the starboard side. No one, however, saw a submarine. The chief engineer, who had served for several years in the Swedish navy, and the captain were convinced that the ship had struck a mine. In this area lay a minefield laid by the German cruiser Kolberg during the raid on Scarborough in December 1914. According to local historians, about twenty vessels had been lost on it by March 1915.

The British Admiralty announced that Hanna had been torpedoed, and that is how she was recorded in post-war lists. Submarines were indeed operating off the east coast of England at this time. According to the British Naval Staff monograph, on 8 March the German command lifted the ban on attacking ships under neutral flags in the waters between the mouth of the Tyne and the Skagerrak. On the morning of 13 March U-23 torpedoed the British steamer Invergyle without warning near Blyth, roughly a hundred kilometres further north. Modern lists of ships sunk by U-boats, such as the uboat.net website, do not, however, attribute Hanna to any submarine. Local historians believe that she probably sank on a mine.

The first neutral victim?

Whatever the cause of Hanna’s sinking, describing her as the first neutral ship sunk by a U-boat is doubtful. Earlier, on 19 February, a German submarine had torpedoed the Norwegian tanker Belridge in the Strait of Dover, but she did not sink. Neutral ships were also lost to mines, such as the American steamers Evelyn and Carib in the North Sea or the Norwegian collier Regin, which in February struck British mines off the coast of Kent. The first neutral ship certainly sunk by a German submarine was the Dutch steamer Medea, stopped and sunk by gunfire in the English Channel on 25 March.

The news of Hanna nevertheless strengthened the conviction in the neutral countries that their flags offered no protection against German submarine warfare. Swedish ships nonetheless continued to sail to Britain, from which Sweden imported coal among other things, and the risk of this trade grew month by month.