BNR 203 - Pollux

The identical Castor and Pollux are self-propelled split hopper barges. The vessel does not have its own dredging equipment, but it can be filled from another dredger (or from an onshore station) and can dump its load quickly underwater. Together with Mustang and Duke II, two powerful AHTS tugboats of Shipyard Gebr. Kooiman and owned by the same client, the vessels will be used in the oil and gas infrastructure projects in the waters north of Russia.

Their major task will be to dump a protective layer of sand and stone on top of newly laid gas pipelines on the seabed and for filling underwater trenches. The owner of the vessels is MRTS JSC, one of the largest Russian companies that delivers turnkey construction of undersea oil and gas pipeline infrastructures.

Castor and Pollux were designed by Kooiman Engineering, Kooiman Marine Group’s own design and engineering division. The four hull halves were built in Turkey and then towed to Zwijndrecht, where the locally built superstructure was placed on top.

Each of the vessels consists of three main parts: a superstructure and two almost perfectly symmetrical half hulls. The hulls are joined on main deck level with hinges in front of and behind the hopper. Close to the hinges on the main deck, but also in the bottom sheeting, a male/female finger joint ensures a strong longitudinal connection between the two halves.

Several metres below the side hinges, in a recess on the outside of the hopper, underwater hydraulic cylinders are mounted which can open and close the hull. The 1,500 cubic metre hopper is equipped with a load-monitoring system to determine the hopper volume and weight. Two fire hoses on the hatch covers of the hopper can clean the remaining sand.

The vessels have an Ice Class rating of 1C, which extends the season for working at high degrees of latitude. They have been approved for use in ice up to a thickness of 40 centimetres. Visible consequences of the Ice Class certification are the larger diameter of the propeller shaft and the size of the gearbox, which must be able to cope with the effects of rotating in ice. The screws have a diameter of 1,800 mm.

Each hull houses a Mitsubishi main engine of 940 kW at 1,600 rpm, and a MAN generator set of 280 kVA. The exhausts pass a dry damper and go upward through the aft deck near the accommodation, by means of casings which are fastened to the hull. These casings are also  used for the air supply and air extraction for the engine room ventilation. The entire electrical system was designed and installed by Kooiman Marine Group’s own electrical systems division: Kooiman Ship Electric.

SHIP TYPE:

1500 m³ split hopper barge, hull, mach, unlimited navigation, aut-ums, ice class 1C

MAIN DIMENSIONS:

• Length o.a.: 77,40 m
• Length perpendiculars: 73,20 m
• Beam moulded: 13,20 m
• Depth moulded: 5,40 m
• Draught: 4,00 m

PROPULSION SYSTEM:

• Main engines: Mitsubishi S12R-MPTAW-3, 2x 940 kW @1600 rpm
• Gearboxes: Masson MM17000
• Propellers: 5 blade, 1,8m / diameter 2,4m
• Bow thruster: Veth Tunnel Thruster VT-150 + B-1 E-engine Leroy Somer, 150 kW @1800 rpm 

AUXILIARY SYSTEM:

• 2x MAN D2866LXE30, 244 kW @1500 rpm (generator set)
• 1x Hatz 2M41, 16.4 kW @1500 rpm (emergency generator)

AUXILIARY DEVICES:

• Vremac split cilinders

ACCOMMODATION:

• Cabins for 8 crew members en 2 passengers