PTC Heavy Lifting Barge

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PTC Heavy Lifting Barge Heavy lifting for marine projects Heavy lifting operations for harbor and offshore projects are usually carried out using either sheerlegs or fl oating cranes. Sheerlegs have the advantage of a greater lifting capacity, while fl oating cranes can revolve (slew) which gives much greater operational fl exibility. Flexibility Mammoet has developed its PTC cranes over 15 years and used them for 17,000 heavy lifts. We have now installed one of these PTCs on a large barge. The key advantage of our design is that the PTC can operate either with the boom fi xed in sheerlegs mode, for the highest lifting capacity, or in revolving mode, for much greater fl exibility when picking up and placing the load. The barge has a relatively shallow draught and can therefore operate close to the shore, even in harbors which have not been fully dredged. This multifunctional design can bring great time-savings when constructing large jetties, other harbor works and offshore structures. The PTC on a barge has many advantages over large sheerlegs, fl oating cranes and jack-up rigs. PTC Mammoet’s PTC cranes, developed in-house, have established a reputation for reliably and safely handling the heaviest loads. Their A-frame jibs are extremely stable and resist side loads. The crane installed on the barge has specially upgraded slewing drives so that it can rotate (slew) with a load on the hook even when the barge has an incline up to three degrees. The ballasting of the barge does not have to be changed during lifting operations, this makes the work safer, quicker and more effi cient. Operating modes In slewing (revolving) mode the whole PTC can rotate a full circle. This movement is relatively quick (around 15 minutes for a typical movement of half a circle). Compared with using conventional sheerlegs, the slewing mode greatly helps to simplify lifting operations and save time. In sheerlegs mode the upper carrier of the PTC is fi xed and the slewing system is not used. Both the PTC’s ballast and the barge itself act as counterweights. This mode provides the highest crane capacity. Finally, the tie-down mode is used during sea voyages. In this mode the crane is fully secured for safe transit. 2 | 3
Key parameters Net lifting capacity: Sheerlegs mode 974 tons at 20 meters radius 173 tons at 76 meters radius Slewing mode 267 tons at 20 meters radius 10 tons at 60 meters radius The net lifting capacity takes account of the weight of the main and auxiliary hook blocks and wire ropes and is therefore fully available for lifting loads. The auxiliary hoist has a capacity of 30 tons. Barge: 100 x 30 meters, draught with maximum load on the hook 4.2 meters Maximum hook height (main hoist) 64 meters Operating envelope The PTC on the barge has a wide operating envelope and can continue lifting up to: - 12.86 m/s wind speed - 0.6 m signifi cant wave height The full lift capacity is available within this envelope, i.e. there is no derating. Certain lifting jobs can be undertaken at signifi cant wave heights up to 1.3 meters. However, when the operating boundaries are approached Mammoet personnel on site will assess the situation and decide if the lifting operations may be continued.
Page 1: PTC Heavy Lifting Barge The perfect
Page 6 and 7: Crane Geometry: Indication A: Load
Page 8: Worldwide specialists in heavy lift

PTC Heavy Lifting Barge

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