MAY 19, 2016—The first of four Ulstein SX157 design ultra-long distance towing and anchor handling vessels was named ALP Striker in a shipyard ceremony last week.
The four vessels, each with a bollard pull of some 300 tonnes, are under construction by Niigata Shipbuilding & Repair, Japan, a subsidiary of Mitsui Engineering & Shipbuilding Co., Ltd. (MES), for Teekay Offshore Partners subsidiary ALP Maritime Services.
The four 88.9 m long and 21 m wide SX157 design ALP Future class vessels will have a service speed of 13 knots and top speed of 19 knots.
With a fuel capacity of more than 3,500 cu.m, they can tow at full power for 45 days, sufficient for non-stop Trans-Atlantic/Indian, Pacific Ocean towing operations without fuel calls.
Each vessel will have four MaK 9 M 32 C propulsion engines, rated at 4,500 bkW at 600 rev/min and three Cat C32 auxiliary generator sets rated at 940 ekW @ 1,800 rpm as well as one Cat C9 generator set to provide emergency power.
All four vessels will each be equipped with two AEM shaft generators rated at 3,150 ekW at 1,200 rev/min.
Each vessel has two Cat BCP1330F main propellers, two BTT625 tunnel thrusters and two BTT419 tunnel thrusters.
The vessels were developed in close collaboration between ship designer Ulstein Design & Solutions AS and ALP Maritime Services.
They will typically tow oil rigs, or FPSOs, from the building yards to the installation site at the oil field.
The vessels are outfitted with DP2 and anchor handling capacity in order to assist during the installation/hook-up phase for the towed objects.
At the time of contract signing, the ocean-going tug market was a new design area to Ulstein, and the largest single contract so far for Ulstein Design & Solutions AS.
In developing the design, Ulstein had to ensure that each vessel had sufficient bollard pull and operational reliability to handle even the heaviest tows by only two vessels. Environmental protection and fuel efficiency were also important criteria.
The vessels are classed with DNV's Clean Design and Ice Class 1B notations, which allow operation also in restricted zones. Their equipment, as anchor handling vessels, includes stern roller, a three-drum winch with 400-ton hoisting capacity, and with chain lockers for rig chain.
The ships have a comfortable and spacious accommodations for 35 persons reflecting long periods at sea.Ulstein is also responsible for the deliveries of main components, such as engines, thrusters and propellers, winch, power distribution and thruster drives, control system and communication system.
The three sister vessels are in different phases of construction. Vessel number 2, the ALP Defender, will be the next one to be completed, while vessel number 3, the ALP Sweeper, was launched on May 7, 2016. The final vessel will be named the ALP Keeper.