Back in the day when allatsea first went ‘offshore’ rather than being your traditional ‘mariner’, a ‘big’ tug, be it deep sea salvage or a very large anchor handler, had around 15000 BHP, which with good props, nozzles and a deep draft, would give around 185 tonnes bollard pull (BP). The article below, from gCaptain, suggests that the day of the 300 tonne BP tug is upon us. Hmmmmmm.
Now when you consider that the diameter of the towing wire required for a tug of 185 tonnes BP was in the region of 76-83mm and that the connection jewellery was then at the limits of assisted manhandling it rather begs the question of how they’re going to make it all work in the practical sense. Wires of what, 120mm diameter and pear links/shackles with a mass of 350kg each.
Deep joy it is not.
Norwegian shipbuilder Ulstein Group announced its big entry into the long-haul ocean towing segment with a design and equipment package contract for four 300 ton bollard pull tugs featuring the unmistakable X-Bow.
The vessels will primarily designed for the towing of large structures over long distances, representing Ulstein’s entry into a new market and the single largest contract for Ulstein Design & Solutions to date.
The four vessels will be built by Niigata Shipbuilding & Repair in Japan for the Dutch company ALP Maritime Services, a new customer for Ulstein, and designed for worldwide operations. They are scheduled for delivered by Q4 2015 and Q1 2016.
The design is called the SX157, developed in close collaboration with ALP, which Ulstein says is expected to deliver in the range of a whopping 300 ton bollard pull and measure 88.9 meters long by 21 meters wide.
Niigata project manager, Shigeru Morioka (middle), UDS managing director, Sigurd Viseth (left) and UDS area sales manager, Ove Dimmen (right). Photo courtesy Ulstein Group
“This is a very important contract, involving activities in a new market for us and with a new customer involved. The contract is a result of close cooperation with the shipyard, the ship owner and our partners in the Norwegian maritime cluster, a cooperation we will work to develop further in the years to come,” says deputy CEO Tore Ulstein in Ulstein Group.
“An oceangoing tug typically tow oil rigs, or FPSOs, from the building yards to the installation site at the oil field,” says managing director Sigurd Viseth in Ulstein Design & Solutions. ”In addition, these vessels are outfitted with DP2 and anchor handling capacity in order to assist during the installation/hook-up phase for the towed objects. The SX157 have fuel capacity to tow over long distances, with the ability of towing at full power for 45 days. This is a niche market where we see that our solutions can be a positive contribution.”
Viseth added: “Within each project we work strategically in order to come up with safer, smarter and greener solutions. ALP refers to these four ships as the ‘ALP Future Class’. When developing the design we had to ensure that each vessel has the sufficient bollard pull and operational reliability to handle even the heaviest tows by only two vessels. Environment and fuel efficiency have also been important criteria. The vessels are classed with DNV’s Clean Design and Ice Class 1B notations, which allow operation also in restricted zones. Additionally, they are equipped as anchor handling vessels including stern roller, a three-drummed winch with 400-ton hoisting capacity, and with chain lockers for rig chain. The ships have a comfortable and spacious accommodation for 35 persons reflecting long periods at sea.”
In addition to providing the design, 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.
Niigata Shipbuilding & Repair is part of Mitsui Engineering & Shipbuilding Co. ALP Maritime Services is subsidiary of Teekay Offshore Partners L.P.
Vessel Characteristics Via Ulstein:
Long Distance Towing
High bollard pull: For the towing of very large floating objects
Also equipped for: Anchor Handling, positioning, mooring
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