Jumbo Shipping was awarded by IMECA with the contract for the ocean transport of two pipelay towers from Gdynia (Poland) to La Rochelle (France). After all assembly works are finished in La Rochelle, the fully assembled tower(s) will be shipped to Okpo (South Korea). Only one tower is shipped each time and therefore four shipments are scheduled to execute the scope of work. In Okpo, the tower will be further prepared for installation on a pipelay vessel. The design of the outrigger construction is part of the Jumbo scope. Saltwater was contracted by Jumbo Shipping to complete the design and strength calculations for an outrigger frame for the purpose of lifting the tower.
The transport requires an extension of the towers, so the vessel’s cranes can reach the lifting points. The center of gravity of the tower is too high to be lifted by the baseframe, hence the lifting points need to be raised. As both towers will be shipped in different transports, the lifting tools require to be re-usable and demountable. The outrigger structure that was developed for the lifting is connected to the tower by means of pins through the structural pad-eyes that are present for fixing the tower to its new mothership. The outrigger structure is built of S355 and the connection points consist of S690 steel quality. The pins are made of 42CrMo4 steel. The cross-braces include threaded rods to be able to adjust the length of the braces after installation of the main lifting structure to improve ease of installation.