Marine pipeline installation system and methods

摘要

The first aspect of the invention relates to a marine pipeline installation system for laying an offshore pipeline, wherein the system comprises a vessel (202) and a pipeline launch tower (206) comprising pipe laying equipment defining a tower firing line (204), which tower (206) is mounted pivotably about a tower pivot axis on said vessel and which is adapted for launching the pipeline in the tower firing line into the sea in a first position of the tower in which the tower is at an angle ± with respect to the vertical. The vessel further comprises an abandonment and recovery (A&R) system comprising at least one A&R cable (213, 713) and a sheave arrangement with one or more sheaves (770, 771) supported by the pipeline launch tower. The invention is characterised in that one or more sheaves of the A&R sheave arrangement are provided at an upper position of the pipeline launch tower, and one or more other sheaves of the A&R sheave arrangement are provided on an A&R trolley which is supported by the pipeline launch tower and moveable substantially parallel to the tower firing line.