OSD-IMT, a division of Offshore Ship Designers, has secured a design contract for two IMT 965 seismic support vessels with a bollard pull in excess of 50 tonnes for China Oilfield Services Ltd (COSL), Beijing.
The vessels will be used to provide a range of support activities to larger seismic vessels which operate continuously for months when conducting seismic surveys. Designed to have a multi-role capability in support of the mother ship, they can be used for re-fuelling, fresh water replenishment, the provision of refrigerated stores and dry provisions, the supply of spares and general stores, emergency towing, and escort support and guard duties.
Refuelling
The IMT 965 carries 980 m3 of cargo oil for refuelling the mother ship, either alongside or ahead. Fuel is pumped to the mother ship from a deck-mounted fuel supply module located on the working deck of the IMT 965. Up to 500 m3 of fresh water can be supplied in a similar way.
Transfer of Goods by Crane
Cold stores and dry provisions totalling 80 m3 can be accessed directly from the working deck of the IMT 965, providing easy access for transfer to the mother ship, either by the ship’s crane or by a crane mounted on the mother ship.
Shadowing the Mother Ship
The operating cycle for the IMT 965 requires it to be on station shadowing the mother ship for prolonged periods. During this time the IMT 965’s activities include keeping passing vessels clear of the streamer arrays, and ensuring that there is a traffic-free area ahead of the mother ship. The vessel is classed with a DP1 notation which will allow it to shadow the mother ship at a pre-set distance for long periods.
Hybrid Propulsion
The main IMT 965 propulsion arrangement is a hybrid system, comprising twin CP propellers, each driven by a medium-speed diesel engine. A PTO/PTI alternator/motor is connected to each main gearbox, and two 360 kWe diesel generators are also provided. The system is arranged such that one main engine can drive both propellers for maximum fuel economy.
The IMT 965 has accommodation for a total of 48 persons, including cabins for mother ship relief personnel. Its principal dimensions are:
- LOA: 64.9 metres
- LBP: 58.2 metres
- Beam: 16 metres
- Draught: 5.65 metres
- Total Deadweight: 1800 tonnes
- Speed: 13 knots
