Rolling bearings speed pipeline laying

The Skandi Navica vessel has successfully laid thousands of kilometres of pipeline off the German coast with the assistance of rolling bearings from INA FAG. Run by the Norwegian company DSND, the Skandi Navica represents one of the world's leading pipelaying vessels and is used in offshore crude oil production. Pipelines are installed on the sea floor and are required to convey oil from the drilling platforms to land or distribution columns. Traditionally, pipes from 12 to 24m in length are welded together, jacketed and lowered on to the seabed. This is an arduous task allowing only one mile of pipeline to be laid a day, and all work has to be completed on board the vessel. However, the Skandi Navica's cable drum principle, with help from INA FAG bearings, involves a giant reel which is lowered into the ocean. The reel weighs 2500 tonnes and stretches 25 metres wide and allows the Scandi Navica to lay 42 kilometres of pipe (with a diameter of 29cm) in one piece. The 2900kg spherical roller bearings, with a machined INA FAG cage, support the gigantic loads on the reel. Gunter Herles, Head of Mining and Processing Application Engineering at, INA FAG, said utmost care was given to selecting the appropriate bearings and its specialists were also required to assist with the bearings' mounting and lubrication issues. 'Apart from the immense loads, we had to take into consideration that the bearings have to compensate for errors of alignment and shaft bending resulting from the reeling movement and deformation of the vessels hull', Gunter said. INA FAG selected a hydraulic method to simplify mounting and dismounting. The company also supplied 3D load rings which permit the lifting of the bearing. For initial lubrication, INA FAG filled each bearing was filled with 73kg of Arconol Load 220, a lithium-soap based grease. Each bearing has to be relubricated with 3-4kg of the grease once a year. Herles said since implementing the cable drum principle, the Skandi Navica has been able to cut time and its associated costs. 'The Skandi Navica has laid several thousand of kilometres of crude oil pipeline with the assistance of INA FAG bearings', he said. 'The vessel returns to harbour when the pipeline has been unreeled and the next piping is wound up'. 'The huge advantage of this method is that all preparations can now be made ashore, making the process so much faster'.