Image of the sunken U-boat U 581

© Rebikoff-Niggeler-Stiftung

The LULA 1000 submersible finds a missing German U-boat

The LULA 1000 research submarine has made a find that will enthrall marine biologists and historians alike: On the sea bed off the Azores islands, it has discovered the German U-boat U 581.

In the early hours of February 2, 1942, the sister ship of the world-famous U96 film U-boat was sunk by its own captain. 42 crew members survived the evacuation at the time, four men lost their lives. Since then, it had been considered lost – until two explorers made the discovery in their deep-sea submersible with a PLEXIGLAS® dome. They discovered the 67 meter-long and almost 800 ton-heavy hull – broken into two parts – at a depth of 870 meters off Pico Island in the Azores.

The PLEXIGLAS® viewing dome for Lula1000

The cockpit for Lula 1000 required a 1,000 kg block. The concave design allows for a viewing angle of 150 degrees. In deep water, the pressure on the cockpit is enormous. At a depth of 1,000 meters, there is a pressure of 1,000 tons on each square meter. Glass would not be able to perform under these extreme conditions. The finishing work of the PLEXIGLAS® block was done by a specialty firm in Baden-Württemberg, which took care of grinding the cockpit.

U-boat with dome of PLEXIGLAS®

These findings have been made possible by a PLEXIGLAS® dome developed by Evonik for the LULA 1000 submersible. Thanks to its special properties, such as having the same refraction index as water, the 14 cm-thick dome is almost invisible under water, meaning that high-resolution, distortion-free videos can be taken even at great depths. Filipe Mora Porteiro, director of Marine Affairs for the regional government of the Azores and himself a marine biologist, was impressed by the first pictures of the wreck: “I’m astonished by the large number and rapid growth of the corals.” There has so far been very little research on the rate at which the many species of coral reefs develop in deep waters.

Lula 1000 finds the missing U-boat U 581

Evonik supports the Rebikoff-Niggeler-Stiftung

When we dive down, we feel as though the dome is not even there.

Joachim Jakobsen
Submersible developer

The discovery of U 581 is due to a husband-and-wife team of German explorers, Kirsten und Joachim Jakobsen. They are the driving force behind the LULA 1000, which is owned by the Rebikoff-Niggeler Foundation. Evonik has been supporting the research projects of the Foundation since 2013. The Jakobsens are in great demand as consultants for deep-sea video recordings for marine biologists and television stations throughout the world.

They began research on the U 581 a few years ago. They talked with witnesses, studied the records and were able to define an area in which the wreck should be located. Using sonar technology, they took an image of the seabed in the area in question between the islands of Faial and Pico in the Azores. They found the wreck during the very first dive in the fall of 2016 and began shooting the film with the LULA 1000.

U 581

The German U 581 U-boat, like the structurally identical U 96 (which featured in the novel and film “Das Boot”), operated from St. Nazaire in France. In the night of February 1-2, 1942, U 581, along with another German U-boat, had been due to sink the damaged British troop transport Llangibby Castle, forced to leave the port of Horta on the Azores island Faial. But U 581 was spotted by a British destroyer and hit by a depth charge near the neighboring island of Pico. The commander gave the order to surface and to open the vents at the water level to sink the vessel.

Further recordings

On September 13, 2016 they struck lucky: From its position and the clearly visible model number (VII C) of the U-boat, U 581 could be identified with high certainty. By means of advanced lighting engineering, the Foundation plans to record more high-resolution pictures, from which a 3-D model of the submarine will be generated. Also on the cards is a TV documentary on the history and scientific value of the sunken warship.