Prefabrication of pipe strings on board of pipe-laying vessels

Abstract

A method of laying pipeline from a vessel () is disclosed. The vessel () includes many pipe processing stations (), arranged across the width of the vessel. In one embodiment, there are two pipe processing areas () separated along the length of the vessel. The pipe processing stations () may be operable in two modes of operation, for example, a first mode of operation where the vessel produces triple joint pipe strings (from three lengths of pipe section welded together) and a second mode of operation where double joint pipe strings are produced, for example, from two single length pipe sections having a significantly greater length than the single length pipe sections used in the first mode of operation. In one embodiment, a triple joint pipe section is part welded in one pipe processing area (), then moved along the length of the vessel () to a different pipe processing area, where further welding operations are performed on the triple joint. In order for the vessel to operate in two modes of operation, the storage bin facilities () for storing single length pipe sections are configured to be able to accommodate different lengths of single length pipe section arranged end to end in a single bin.