This paper describes the design, building and functioning of a ship for single-lifting of topsides of offshore platforms up torn53,000 short tons (48,000 metric tons) and jackets up to 27,500 short tons (25,000 metric tons).rnThe vessel will have a wide slot at the bow which fits around platform substructures and is equipped with a hydraulicallyrnoperated topsides lifting system. For installing or removing platform jackets she will have a system of two tilting lift beams atrnthe stern.rnVery large lifts can substantially reduce offshore hook-up costs in topsides installation.rnIn topsides decommissioning, single-lifting can make laborious module removal unnecessary. The offshore environment isrnspared and the safety of personnel at work offshore is enhanced.rnIn rough areas such as the North Sea, a motion elimination system is a necessity to avoid re-impact of a lifted structure onto itsrnbase structure, which could cause severe damage.rnThe vessel may not always find sufficient occupancy in very heavy lifting work and therefore will also be a pipelayer with anrnS-lay tension capacity up to 2200 short tons (2000 metric tons) for installing heavy pipelines in shallow and deep water.rnThe building of the vessel and equipment is in progress; she is scheduled to be commissioned by the end of 2013.
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