The Turkish shipbuilder Sanmar and a UK island council have confirmed initial reports that two escort tugs have been ordered for Scottish island operations. Orkney Islands Council Marine Services has ordered two azimuth stern drive (ASD) tugs of Robert Allan design, for £6.1M (US$7.9M) each, from Sanmar Shipyards. These will be 32-m tugs with fire-fighting systems and winches for escort duties.

They will be built to an adapted RAstar 3200-SX design at Sanmar’s Altinova facility in Turkey, as the first of a new series of Kocaçay-class tugs. Delivery of the first tug is due around May 2020, with second tug three months after that.

With free running speeds of more than 13.5 knots with an expected bollard pull of up to 84 tonnes ahead, they will be capable of safely escorting ships at up to 10 knots.

Their main propulsion will incorporate a pair of Caterpillar 3516C diesel engines, each developing 2,350 kW at 1,800 rpm driving two Rolls Royce type US255 P30 Z-drives, with 280 cm diameter controllable pitch propellers in ASD configuration.

Sanmar projects director Ali Gurun explained how the shipyard worked with Orkney Islands Council Marine Services to adapt the design.

“We visited the port and spent time with the team and the crew and tried to understand the operational needs of the area,” he said. “Then we modified the design with our designers not only according to the tender requirements but also according to the demanding conditions of Orkney.”

Robert Allan contracts manager Oben Naki said the tug design was adapted for minimal draught and maximum performance requirements.

“Unlike other shallow-draught designs that use a compromised hullform to achieve a reduced draught, these RAstar 3200-SX are still expected to deliver high astern bollard pulls of up to 77 tonnes,” he said. “Using the latest Robert Allan escort analysis software the tugs are capable of safely escorting ships at up to 10 knots with predicted steering forces over 70 tonnes and braking forces of almost 120 tonnes.”

These will have forward and aft winches and will be much more capable than the present tugs, said Orkney Islands Council’s harbour master and head of marine services Brian Archibald. “The current three tugs have served us very well indeed for over 30 years,” he said.

“However, in order for Scapa Flow to maintain its faultless safety record and to continue to thrive as an income generator for Orkney, the new tugs are essential.”

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Mr Archibald said the council had agreed to purchase two new tugs with greater power and manoeuvrability than its existing ones.

Three tugs are currently based in Orkney: Harald, Einar and Erland, which were built between 1989 and 1992. These tugs provide a 24-hour, year-round towage service, and are involved in a broad range of operations.

In addition to considerable tanker traffic linked to the Flotta oil terminal, Scapa Flow regularly hosts ship-to-ship transfer operations of crude oil, gas and other products, and has proved to be an ideal location for the long-term anchorage of accommodation rigs.

Orkney new tugs particulars

Type: ASD escort

Design: RAstar 3200-SX

Length, oa: 32 m

Breadth: 13 m

Maximum draught: 5.47 m

Bollard pull: 84 tonnes ahead

Free running speed: 13.5 knots

Engines: 2 x Caterpillar  3516C

Propulsion: 2 x Rolls Royce US255 P30 Z-drives