A test of the multipurpose pontoon (MPP) and its specialized submarine frame SDT (Submarge Dumping Tool) took place at the dry dock of Gdynia's Crist Shipyard on May 17 at 10:00 am.

The SDT underwater frame is the main key performance element of the MPP vessel. Its task is to prepare the ground for the tunnel elements by driving a layer of specially prepared gravel with very high accuracy before the foundation of the prefabricated concrete tunnel segments. Subsequently, the laid segments are backfilled to strengthen their foundation.

The purpose of the trial was to check the specialized equipment installed on the ship to raise the frame, verifying the transport position along with anchoring the frame to the ship.

The test was fully autonomous, as it was carried out using the ship's equipment - starting with power generators, electrical and automatic apparatus, and ending with hydraulic actuators (the frame is equipped with nearly 50 hydraulic cylinders).

The SDT frame, including equipment, weighs more than 700 tons and is saturated with equipment, specialized apparatus and measuring instrumentation. It is the highest level of technology, designed and constructed to the highest offshore standards.

The SDT trial, as well as the entire project to build the MPP multipurpose pontoon (NB131), is another unique project on a global scale in which Crist is participating.

The construction of this vessel officially began with sheet metal cutting on October 26, 2021. The ordering party is the FLC (Femern Link Contractors) consortium, which is responsible for the entire tunnel construction project. According to the contract, Crist shipyard was to build both the unit itself and the drop device (known as SDT), whose job will be to lay gravel on the seabed, on which in turn the tunnel elements will be set. The device is remotely controlled. It will be lowered from under the vessel's hull to 46 meters below the waterline, where the foundations will be laid. The precision of their placement is ensured by state-of-the-art positioning technology.

Crist collaborated with StoGda design office on the project.

The vessel has a hull length of 130.2 meters, but its overall length, including the transmission belts, will be 149 meters with a width of 48 meters. The pontoon will be able to accommodate 19 people. The unit is equipped with two gravel chambers that will hold 14,000 tons of gravel.

The tunnel, in the construction of which the Crista-launched pontoon will work, will connect the German port of Puttgarden and the Danish Rødbyhavn on the island of Lolland, and thus Scandinavia and Germany. The 18-kilometer structure will accommodate a highway and a railroad. It is expected to reduce train travel between Hamburg and Copenhagen from 5.5 to 3 hours.

Further advanced testing will take place in the following weeks, and the unit will be handed over to the end user during the summer.