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    New generation heavy lift ship delivered

    Yard News // March 6, 2000
    Offshore Heavy Transport in Norway has taken delivery of the first of what it describes as a new generation semi-submersible heavy lift vessel, and says a second vessel, built to the same design, is due to be delivered in late March or early April.

    The new vessel, the Black Marlin loaded the new drilling rig Deepwater Nautilus in Korea and is now underway to US Gulf to deliver the rig to owners, RB Falcon (see photo).

    The two ships were built simultaneously at CSBC Shipyard in Kaohsiung, Taiwan. Capable of loading very large floating cargo or other types of extremely large cargoes, the ships are the largest of this type ever built. The cargo deck is considerably longer than existing ships, and because of their large size, larger cargoes than ever before can be dry transported safely, claims the owner.

    Designed specifically to transport high value, complex cargoes, the Marlin class heavy lift ships have a stowable deck 178.20m long and 42m wide, thus amounting to in excess of 7,216 m2.

    The only obstructions on the deck are two stability towers aft, but the smaller of the two towers (to the port side) can easily be shifted to any other place on the deck, and the larger stability tower on the starboard side aft can be removed for specialprojects.

    Their size and other characteristics make the two ships especially suitable for transporting the largest semi-submersible rigs, jack-ups, TLPs and SPAR buoys built to date. According to the owners, the marlin class will be capable of carrying semi-submersible rigs of up to 30,000mt.

    The large free and open deck area makes the ships very suitable for skidding or rolling large cargoes onboard. The ballasting system is specially designed for such operations. The Marlin class is equipped with four high capacity ballast pumps with a total capacity of 12,000 MT per hour. With this capacity the new class can perform loading and discharge operations quickly and efficiently, a facility which will be particularly useful when weather limits the time available.

    In addition to the pumps, a total of 36 ballast tanks can be free-flooded, thus reducing the critical contact period. With all four ballast pumps in operation and flooding of tanks, the ship can alter its draught by 1.0m in just 20 minutes. When the cargo deck is submerged the same change in draught can be accomplished in just five minutes.

    Uniquely for vessels of this size, they also have double bottom and double deck tanks, which provides a high level of flexibility when it comes to optimising ballasting for small or large cargoes, and the ability to tune GMt to any desired level.

    The company says a number of new features have been built into the ballast system. The ships have double redundant ballast lines and valves, which make it possible to pump directly from any tank to any other. This will be especially useful during skid-onoperations, to compensate for large heel moments and tidal changes.

    All main valves are operated remotely from a control room overlooking the cargo deck area. A computer system is connected to double redundant level gauges in each tank.

    All loading parameters are calculated to a very high level of accuracy using a realtime computing system, even when the ship and cargo is submerged. The same computer can also be used to simulate complex ballasting operations to address all safety features before execution and to prepare safe ballasting procedures.

    The newbuildings have a standard set of six ballast tanks arranged longitudinally. With two longitudinal bulkheads there are three sets athwarthships.

    A unique feature for such a large ship is that they also have double bottom and double deck tanks. Altogether there are 54 large tanks in the main cargo area. In addition to those 54 tanks, there are another 14 tanks fore and aft. With 68 tanks a great choice and flexibility make it easier to find optimum ballast conditions to reduce motions when transporting 'awkward' or difficult cargoes.

    The Marlin class ships are fitted with a main engine capable of more than 17,000bhp continuous output, sufficient to provide an estimated speed of 14.5kt on design draft.

    The hullform and size of the newbuildings is such that they should experience little loss of speed due to high seas, and their fuel capacity is sufficient to sail half way around the world without refuelling.

    The ships are powered by a proven, reliable, slow speed diesel engine combined with a large-diameter controllable pitch propeller. Best reliability is ensured by direct drive shaft with no gearboxes. A Becker rudder considerably increases steering reliability under slow speed and extreme weather. A huge bow thruster is installed in the bow.

    Apart from the two anchors forward the ship is equipped with a heavy duty Bruce anchor aft. This anchor is connected by chain for improved holding power.

    The ships are equipped with five electrically driven winches for cargo positioning, four of which have double drums.

    As Offshore Heavy Transport explained to Offshore Shipping Online, the Marlin class has hullform is deep compared to a conventional barge shaped hull.

    Together with the large deadweight capacity of the new class vessels, a very high freeboard is achieved and maintained even with heavy cargoes loaded onboard the ship.

    A large freeboard will provide cargoes carried by the Marlin class with a high level of protection heavy seas, a fact that is of particular relevance to large, overhanging and more vulnerable cargoes.

    Main particulars

    Length overall: 217.50m
    Length between perpendiculars: 206.57m
    Breadth (moulded): 42.003m
    Depth (moulded): 13.304m
    Summer draught: 10.079m
    Deadweight: 57,021mt
    Gross/Net: 37,938

    Submerged depth above deck: 10.0m
    Maximum deck load: 27.5 mt/m2
    Free deck length: 178.20/157.20m
    Free deck area: in excess of 7,216m2
    Main engine output: 12,640 kW
    Bow thruster: 2,000 kW
    Speed: 14.0kt
    Range: 25,000nm
    Accomodation: 50-55
    Built by: CSBC, Kaohsiung

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