Robert Allan delivers first-in-class designed escort tug

Photo courtesy Robert Allan Ltd.

IRSHAD, a joint venture between ADNOC and Lamnalco, have taken delivery of their latest high-performance terminal support/escort tug from Astilleros Balenciaga SA, of Zumaia, Spain. The Alaryam is the latest delivery of the widely acclaimed RAstar Class true escort tug designs from Robert Allan Ltd., Naval Architects of Vancouver, BC., but in fact was the first tug of the RAstar series ever designed. The design was the subject of an extensive series of model testing to prove the concept.

This RAstar 3600 Class vessel was designed to perform a wide range of tasks, including ship-handling, LNG and Oil tanker escort, fire-fighting and oil spill response/recovery duties. The RAstar class hull form ensures the highest standards of both escort towing capability and superior sea-keeping in the heavy sea conditions encountered in these operations.

The Alaryam is classed for unrestricted duty and accordingly was built to Lloyd’s Register of Shipping Class: 100 A1 Escort Tug, Fire-Fighting Ship 1 (2,400 m3/hour), Occasional Oil Recovery Duties LMC, UMS, EP, MCM, and in full compliance with SOLAS and International Loadline regulations.

The particulars of the new tug are as follows:

Length Overall     – 35.80 metres
Beam, Moulded     – 13.50 metres
Depth, Moulded     – 5.92 metres
Operating Draft, Maximum     – 5.87 metres
GRT     – 656

Tank Capacities are:
Fuel Oil     – 284 m³
Potable water     – 30 m³
Fi-Fi foam capacity     – 32 m³

Propulsion comprises a pair of Wärtsilä 8L26 diesel engines, each rated 2600 kW at 1000 rpm, and each driving a Wärtsilä model CS275 controllable pitch Z-drive unit. With this propulsion system, the vessel performance satisfied all expectations, with a recorded Bollard Pull of 84 tonnes and a free-running speed of 14.7 knots.

The Alaryam is very well-equipped for its various towing and escort duties: the fore deck is fitted for typical ship-handling and escort work, with a Karmoy double-drum hawser winch, Karmoy tow-pins and Karmoy anchor windlasses. The winch features a towline render / recover system for escort operations and has capacity for 200 and 150 metres of 76 mm diameter high strength towline.

The aft deck is fitted with a 100 tonne SWL towing bitt and Mampaey towing hook. Also fitted are a 10 tonne capstan, and a hydraulic knuckle-boom deck crane of 15 tonne-metre capacity.

The Alaryam is outfitted to the highest standards for an operating crew of up to twelve (12) persons. Facilities on board include spacious crew rooms for the full complement in two (2) single cabins, each with individual en-suite toilet and shower facilities, and five (5) spacious double cabins. Public spaces include a generous combined lounge/mess area and a fully equipped and modern galley.

In common with the majority of Robert Allan Ltd. designed tugs, a great deal of attention was paid throughout the design process to mitigate the propagation of noise and vibration. This includes the essential resilient mounting of the main engines, isolation of all exhaust system components, and the extensive use of visco-elastic floating floor systems throughout.

The layout of is illustrated on the accompanying General Arrangement drawing.

Illustration courtesy Robert Allan Ltd.

Source: Robert Allan Ltd., Naval Architects

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