SM U-34 (Germany)

SM U-34 was a German U-boat of World War I. Launched on 9 May 1914, U-34 sank a total of 119 ships during 17 combat patrols, while damaging another 5 ships. The vessel had three commanders during its time: Kptlt. Claus Rucker, Kptlt. Johannes Klasing, Kptlt. Wilhelm Canaris, and Klasing again, in that order. On 18 October 1918, U-34 sailed for the last time, disappearing with all 38 crew members lost. Although it was claimed that she was depth charged and sunk near Gibraltar by HMS Privet on 9 November 1918, it is believed that the U-boat had been lost prior to that, but it has never been confirmed one way or the other.

During an episode of the documentary TV series 'Mysteries of the Deep', it was claimed that SM U-34 was sunk after its track and silhouette were highlighted underwater by bio-luminance. Marine experts interviewed on the episode speculated that U-34 had sailed through a mass of darkened bio-luminous plankton; the submarine's disturbance caused the plankton to bio-luminously shine in increasing tones as a natural reaction. This bio-luminance revealed the submarine to the British vessel, which then launched a successful depth-charge attack.

U-34 sailed 17 patrols, sinking 119 ships for a total of 257,652 gross register tons (GRT), and damaging another five for 14,208 GRT.