The non-profit Rebikoff-Niggeler Foundation plans to seek out and film the legendary giant squid Architeuthis in its natural habitat, using a submersible constructed specifically for this purpose. A central component of the submersible "Lula1000" is a large viewing dome made of Plexiglas.
The submersible Lula1000 can move autonomously on dives. After the dive down, Joachim Jakobsen controls it from the hull of the catamaran Ada Rebikoff, the only submarine tender boat in the world. (photo: Christoph Bauer/Evonik Industries)
Underwater pioneers Kirsten and Joachim Jakobsen, the driving force behind the Rebikoff-Niggeler foundation, have begun their search for the giant squid Architheutis. They had been waiting for the submersible "Lula1000" to gain approval, which was granted by the classification society Germanische Lloyd. With that, the 7.5-metre-long submersible is now cleared to dive to a depth of 1,000m below sea level. The Plexiglas viewing dome plays a key role in the exploration of the deep sea with this manned exploration vessel. The dome, with a diameter of 1.4m, was manufactured and shaped in a special process by Evonik.
Joachim Jakobsen, who controls the Lula1000, and his wife Kirsten Jakobsen, who is in charge of the film shoot, behind the Plexiglas viewing dome. (photo: Christoph Bauer/Evonik Industries)
The making of the PMMA concave cockpit
The production of the viewing dome was a challenge for Evonik as the required Plexiglas, which was produced by the Acrylic Polymers Business Line, had to be processed without affecting its optical properties. Evonik had to find new work methods to accommodate the custom order. "The challenge was to turn a block of Plexiglas into a hemisphere without affecting the optical quality or impairing the material strength," explained Wolfgang Stuber, Product Manager in the Evonik Acrylic Polymers Business Line. The team therefore came up with a specialised process, in which an optically perfect, pre-approved block is reshaped with the help of heat and pressure. "The patent application is pending," reports Stuber. Representatives of Germanische Lloyd were on site during the development work and then certified the procedure.
A sighting of a sixgill shark. The PMMA viewing dome had to be processed without affecting its optical properties. (photo: Rebikoff-Niggeler foundation)
The cockpit for Lula1000 required a 1,000kg block. The thinnest section of the finished viewing dome has a thickness of 14cm. The concave design allows for a viewing angle of 150°. In deep water, the pressure on the cockpit is enormous. At a depth of 1,000m, there is a pressure of 1,000t on each square meter, the equivalent of 1,100 Smart cars stacked on top of a mid-sized flat TV screen. Glass would not be able to perform under these extreme conditions. The finishing work of the Plexiglas block was done by a speciality firm in Germany, which took care of grinding the cockpit. The viewing dome of the Lula1000 has a diameter of approximately 1.40m. Another Plexiglas dome with a diameter of 61cm seals the entry hatch at the top.
The concave design of the viewing domw allows for an viewing angle of 150°. (photo: Rebikoff-Niggeler foundation)
Architeuthis, the giant squid
Little is known about the giant squid, which features in many myths and stories. Until the second half of the 19th century, sightings of giant squid were considered sailors' yarn. This belief was disproved when remnants of dead giant squids were discovered. The animals, which have eight arms and two tentacles directly attached to their head, can reach a length of more than 10m. Their natural enemies are sperm whales, which can dive to depths of up to 3,000m and feed on squids as their primary diet. The same whales alerted the researchers to the presence of Architeuthis near the Azores. Female whales will hunt for food at depths of 500 and 1,000m while rearing their young. The Azores, where the gigantic ocean creatures can often be observed directly from the beach, are known as one of the world's largest whale habitats.
www.evonik.com/lula-1000
http://rebikoff.org
