Location: At sea
Project: Special deep sea tower construction
Challenge: High resistance welding on trusses
Market: Industry
A company specialising in CPT (Cone Penetration Testing) systems for the offshore Industry were looking for an application of truss techniques in one of their CPT systems – the Rosen - and thought that the Prolyte Group would be an excellent partner.

So, what is CPT? CPT is used for geotechnical soil investigation using specially developed probes or “cones”. The Rosen is a seabed penetrometer designed to examine and map the seabed at depths of up to 2000m using cones with up to 5m penetrations. Normally, on shore the tubes would be lengthened per metre; however on the ocean floor this is not possible.

Therefore Prolyte was asked to develop a tower that could be mounted on the ship, with the tubes and cones at the right probing length. With the cones and tubes mounted in the “Roson Truss”, the complete installation could be lowered to the ocean floor.

While the Technical Director of Prolyte, explained a thing or two about the tower construction, it was clear that there were still several questions to be answered: A truss tower to be used at the bottom of the ocean at a depth of 4000 meters? The water pressure would be…what was the formula again? At the surface, 1 bar at 10 meters depth, 2 bars at 20 meters depth and so on. What about 4000 meters? What kind of material would be needed to withstand this kind of pressure?

After feasibility study the order was given to produce eight of these “Roson Truss” systems. The basic design was based on the Mammoth truss concept, with the right welding guide we could weld the “Roson Truss” in different stages.

Not all welders are capable of this specific job. Inspection representatives from the customer were impressed by the guaranteed tolerances we were able to achieve, and granted production approval. This is yet another prestigious project that Prolyte can be proud of. If we’re ready for the depths of the ocean, we’re ready for anything!