Marine pipe laying system method and hoisting device

摘要

The invention relates to marine pipe laying. For laying of an offshore pipeline, a system is used having a hoisting device (2). The hoisting device (2) comprises a tower (3) with a tower top side (3a) provided with cable pulleys (4). Furthermore the hoisting device (2) has a traveling block (5) which is displaceably attached to the tower (3). The traveling block (5) comprises a first block (51) and a second block (52), both provided with cable pulleys (6,7). The first block (51) is provided with a clamp (10) for holding a pipe section (20) to be connected to the pipeline (21) as well as for lowering the pipeline (21) after the pipe section (20) is connected to the pipeline (21). The hoisting device (2) has a hoisting cable (8) and a winch (9), the hoisting cable (8) being guided over the cable pulleys (4,6,7) on both the tower top side and the traveling block (5). The traveling block (5) is moveable with respect to the tower (3) by operation of the hoisting winch (9). The first block (51) and the second block (52) are adapted to be releasably coupled, in which coupled state they can travel along the tower (3) as a unit and are able to support the weight of the pipeline (21). The second block (52) can be locked to the tower (3), such that the first block (51) can travel along the tower (3) while the second block (52) remains stationary with respect to the tower (3).