Cheoy Lee’s fab four

Named SL Jamba, SL Korowi, SL Logohu and SL Siage, the tugs have arrived in Papua New Guinea to provide towage and marine services at new LNG export facilities being developed by Exxon Mobil PNG/Kutubu LNG.

All four ASD tugs have been built to a Robert Allan Ltd (RAL) RAstar 3200 design and measure 32.00m in length overall, with a beam (moulded) of 12.80m, a depth (moulded) of 5.37m and a maximum draft of 5.80m. The design and construction meet the class requirements of Lloyd’s Register of Shipping: 100A1, Escort Tug, LMC, UMS, Fire-Fighting Ship 1 with Water Spray, Unrestricted Voyages, IWS.

The unique ‘sponsoned’ hull form of the RAstar Class tugs gives these vessels a level of crew safety and comfort that will enable them to operate in conditions previously deemed unworkable. The RAstar hull form, developed and used exclusively by RAL has been proven in both model and full-scale testing to provide significantly enhanced escort towing and seakeeping ability. The motions and accelerations are significantly less than those of comparable sized, wall-sided ‘standard’ tug hulls.

Main propulsion system for these RAstar 3200 class tugs consists of a pair of Caterpillar 3516C HD high-speed diesels, each rated 2240 kW at 1800 rpm (a total of approx. 6000bhp). The main engines are coupled to a pair of Schottel SRP 1515 fully azimuthing propulsion units incorporating controllable pitch propellers.

Two identical auxiliary generators, each with a power output of 100ekW supply electrical power onboard, supplemented by a small harbour generating set.

The principle tank capacities are: Fuel oil – 193m³, Fresh water – 35m³ and fire fighting foam – 16m³.

It is understood that on trials the SL Korowi achieved a bollard pull of 75 tonne towing ahead, 79.75 tonne astern and a free running speed of over 14 knots. A similar performance was achieved by its sister-ships.

All four tugs are virtually identical with one major exception, two vessels SL Logohu and SL Siage have a towing winch on the after deck, a stern roller and deck crane. The remainder a radial type tow-hook installed aft. All four tugs are fitted with a Kraaijeveld winch on the foredeck for shiphandling

The tugs are well fendered for push-pull shiphandling and other duties with a mix of large diameter cylindrical rubber, ‘D’ section extrusions and ‘W’ section block mouldings.

The wheelhouse is designed for maximum all-round visibility and provides maximum visibility to both fore and aft deck working areas. These vessels have been fitted out with full accommodation for maximum crew of eight. The master’s and chief engineer’s cabins are located on the main deck, with three additional two berth crew cabins on the lower accommodation deck. The galley and a spacious mess/lounge room complete the deckhouse arrangement.

By Jack Gaston