A hundred year old World War I mystery solved – SM U-26 has been found

Helsinki, Finland – June 2nd, 2014 – Free for immediate release

In the beginning of World War I the German submarine U-26 disappeared without a trace in late August 1915, somewhere in the northern Baltic Sea. Almost a hundred years U-26 was believed to have sunk either by a mine or a technical failure around the west or south-west side of Estonian islands Hiiumaa and Saaremaa, or in front of Libaun (present-day Liepaja, Latvia).

Until Now.

Badewanne – a Finnish wreck diving team – has identified the wreck of SM U-26 in the western Gulf of Finland. U-26 never got out of the Gulf of Finland, instead she was destroyed by a Russian minefield, which was laid down to block German access to the Gulf of Finland.

U-26, which was commanded by Lieutenant commander Egewolf von Berckheim, was maybe the most successful German submarine operating in the Baltic Sea during World War I. The young naval officer and Freiherr von Berckheim was one of the first “aces” of the new and technical submarine branch. Right in the beginning of World War I U-26 immediately sank the Imperial Russian armoured cruiser Pallada in October 1914 outside of Hanko. During 1915 U-26 sank three more ships. In the Sea of Åland the Finnish merchant vessel Fråck and in the Gulf of Finland Russian minelayer Yenisei and transport ship Pechora. The luck of U-26 ‘s crew however turned in the end of August 1915, and von Berckheim and his crew never returned from the Gulf of Finland to their base in Kurzeme Region.

The wreck of U-26 and her crew rest in the same waters off Hanko as her largest and most prominent victim, the armoured cruiser Pallada. The submarine has sunk stern first into the mud, in such a way that a big part of the hull still lies above the mud, including the conning tower. The wreck is slightly leaned on her port side, and the bow is pointing upwards loose and off the bottom at an angle of about 15 degrees. It seems that U-26 was hit on the surface by a mine which has exploded in the stern.

The wreck is in a very good condition and the lightweight outer shell of the hull is practically intact. The natural environment of the Baltic Sea has protected the wreck superbly, low salinity and oxygen-poor bottom water have slowed down destructive corrosion processes. U-26 had a double hull design and the pressure hull is not visible at all. There is only some visible damage caused most apparently by a trawling net, which has stuck on the wreck years ago. Although most of the trawl is gone, there are still some parts left. U-26 is no doubt the most well preserved German World War I U-boat wreck in the world. The submarine took down its entire crew of 30 sailors. By coincident, U-26 was located and the side scan sonar images were taken exactly 100 years after U-26 was commissioned.

Maritime-wise U-26 has sunk on a high traffic sea lane in a critical location. Diving at the wreck site without compromising maritime safety and sea traffic is only possible with special arrangements and co-operation with the Finnish maritime authority.

Submarine warfare during the World War I

During World War I Germans had 373 different submarines, or “U-boats” (Unterseeboot)*. Out of these submarines 203 were lost during the war, each fordifferent reasons*. Among these many different reasons history books usually mention only “Verschollen” (missing in english) while the cause of the loss and final resting place remain unknown. During World War I U-boats proved to be very effective and dangerous weapons, because technically sophisticated counter weapons and tactics did not exist at that time. The success of German U-boats was however limited by the concept of “limited submarine warfare” – rules that Germany followed most of the time during World War I. U-boats were not allowed to sink merchant ships without a warning unless they were a part of a convoy. Instead, the ship was stopped, examined, and if any of the war prohibition goods were found on board, the vessel was scuttled either by explosives or artillery fire. Among many others, this was the fate of the Finnish merchant vessel Fråck.

The most famous U-boat captain during World War I,  Lothar von Arnauld de la Periere, sunk 194 vessels, a total of 453,000 grt. During World War II the most successful U-boat ace Otto Kretschmer sunk “only” 44 ships, totaling 266,000 grt.

U -26 was  one of the four “U-23” class submarines that were built (U-23 – U-26). U-26 was commissioned in 1914, before the war began. The first fifty ocean going U-boats were quite similar. Over time, the following U-boat types were developed and modified in a series of only a few boats.

*) The numbers vary in different sources.

U-26 specifications

  • Type displacement: 670 tons (surfaced)
  • Dimensions: 64.7 x 6.3 x 3.45 (length x width x draft)
  • Maximum speed: 16 knots surfaced, 9 knots submerged
  • Armament: 4 x 50cm torpedo tubes (two bow and two stern), 6 torpedos


Media contacts & further information:

Jouni Polkko, jouni.polkko(at)fmi.fi, +358 50 526 6661

Juha Flinkman, juha.flinkman(at)ymparisto.fi, +358 40 750 3911

Badewanne diving team

Badewanne is a non-profit organization representing a group of voluntary divers that have been documenting shipwrecks in the Gulf of Finland (known during WW II as “Badewanne”) for more than 15 years. We are a multi talented team with a broad skill set on underwater video, still photography, drawing & painting, 3D modelling, underwater engineering, marine biology and environmental sciences.

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