RORLEGGNINGSFARTYG FOR UTLEGGNING AV EN AV STORA ROR KONTINUERLIGT HOPSVETSAD RORSTRENG

摘要

An underwater pipe laying vessel for laying a continuous pipeline, applying what is known as the "J" shape pipe laying method, uses shorter lengths of pipeline welded together on board end to end to form pipe assemblies; the pipe assemblies are stored and subsequently transported to a pipe laying boom unit which guides pipe assemblies to be welded end to end to a pipeline which is already in the "process of laying" under the vessel. The pipe laying boom is located substantially in the center of the vessel and is swivelled about a horizontal axis which is perpendicular to the length of the vessel; the boom includes a flash butt welder and an underlying jacketing-unit for suitably treating a welded surface of the pipeline to prevent subsequent corrosion; a pipeline section guide and pipeline section support located under the jacketing-unit assist in supporting and guiding the treated pipeline for proper positioning. Shorter lengths of pipe and the pipe assemblies are stored, handled and moved on board the vessel expediently on conveyors and rollers in such manner that the length of each pipe and pipe assembly is always parallel to the longer axis of the vessel. The invention provides very efficient and speedy pipe laying operation which is monitored from a control station on board the vessel.