SM UB-6 - Early Career

Early Career

The submarine was commissioned into the German Imperial Navy as SM UB-6 on 8 April under the command of Kapitänleutnant Erich Haecker, a 29-year-old first-time U-boat commander. On 19 April, UB-6 joined the other UB I boats then comprising the Flanders Flotilla (German: U-boote des Marinekorps U-Flotille Flandern), which had been organized on 29 March. When UB-6 joined the flotilla, Germany was in the midst of its first submarine offensive, begun in February. During this campaign, enemy vessels in the German-defined war zone (German: Kriegsgebiet), which encompassed all waters around the United Kingdom were to be sunk. Vessels of neutral countries were not to be attacked unless they definitively could be identified as enemy vessels operating under a false flag.

The UB I boats of the Flanders Flotilla were initially limited to patrols in the Hoofden, the southern portion of the North Sea between the United Kingdom and the Netherlands. Although UB-4 had made both the first sortie and sunk the first ship of the flotilla in April, UB-6 sank the first warship credited to the flotilla. On 1 May, Haecker spotted two old Royal Navy destroyers, Brazen and Recruit, about 30 nautical miles (56 km) southwest of the Galloper light vessel. Just before noon, Haecker launched a torpedo that hit Recruit and split the 335-metric-ton (369-short-ton) displacement ship in half, killing 34 men; 26 men were rescued. One month later, on 1 June, UB-6 sank what would be her largest ship, the British cargo ship Saidieh, of 3,303 gross register tons (GRT). Saidieh was en route to Hull from Alexandria with a load of onions and cottonseed when UB-6 sank her at the mouth of the Thames; eight crewmen lost their lives in the attack.

In late June, Korvettenkapitän Karl Bartenbach, head of the Flanders Flotilla, used UB-6 to test a theory that British defenses in the Straits of Dover—anti-submarine nets and mines—were not insurmountable. On the evening of 21 June, UB-6 departed Zeebrugge for a round-trip to Boulogne. UB-6 sailed past Dunkirk on the surface and made Boulogne in the early morning of the 22nd, having to crash dive once during the voyage when discovered by a British destroyer. UB-6 immediately made the return trip and arrived safely at Zeebrugge later the same day. Three other UB I boats, UB-2, UB-5, and UB-10, soon followed with patrols in the Channel, but bad weather and fog hampered the boats and none had any success. Even though no ships were sunk during these forays into the English Channel, by successfully completing their voyages, the submarines helped further prove the feasibility of defeating the British countermeasures in the Straits of Dover.

On 12 July, while patrolling between 18 and 23 nautical miles (33 and 43 km) off Lowestoft, UB-6 attacked five British fishing vessels, sinking four of them. All four of the sunken ships were smacks—sailing vessels traditionally rigged with red ochre sails—which were stopped, boarded by crewmen from UB-6, and sunk with explosives. Two weeks later, UB-6 torpedoed and sank the 406-ton Firth 4 nautical miles (7.4 km) from the Aldborough Napes Buoy. UB-6 sank the 57-ton Leander, another smack, on 11 August.

Germany's submarine offensive was suspended on 18 September by the chief of the Admiralstab, Admiral Henning von Holtzendorff, in response to American demands after the sinking of the Cunard Line steamer Lusitania in May 1915 and other high profile sinkings in August and September. Holtzendorff's directive ordered all U-boats out of the English Channel and the South-Western Approaches and required that all submarine activity in the North Sea be conducted strictly along prize regulations. It would be five months before UB-6 would sink another ship.

In mid-November, Oberleutnant zur See Ernst Voigt succeeded Haecker as commander of UB-6; it was the first U-boat command for the 25-year-old Voigt. Under his command, UB-6 sank her next vessel in January 1916. The 57-ton smack Crystal was boarded and sunk by explosives 25 nautical miles (46 km) southeast of Southwold on the 27th.