First two of six head for Port Hedland

Tugs & Towing’s look beyond Europe for news of international interest takes us to the Port Hedland bulk export terminal which has been making news in the towing world including the recent order for six 32m Damen-built Rotortugs for Pilbara Marine Pty Ltd (see MJ April 2017). The significant investment in the terminal’s towage services is continuing apace with this order for Robert Allan Ltd designed escort tugs.

The six-vessel order covers RAstar 85 class tugs built by ASL Shipyards Singapore, custom designed to meet the ‘formidable environmental conditions and demanding operational requirements’ of the world’s busiest bulk commodity port by tonnage. Environmental conditions include: very high air and water temperatures, airborne ore dust, strong currents in a narrow channel and 35 knot winds and 3m significant wave heights.

Escort steering forces are achieved through a sponsoned hull-form incorporating a foil-shaped escort skeg along with an aft biased ‘Wide-A’ escort staple. Main particulars include: length 34.94m, beam 14.75m, depth 6.07m and draught (260dwt) 6.18m. Principle tank capacities include 225m3 of fuel oil and 32m3 of fresh water.

Main machinery comprises a pair of IMO Tier III compliant Caterpillar C175-16 diesels rated 2,550kW at 1,800rpm with propulsion via Schottel SRP 4600 thrusters with 2.7m controllable-pitch propellers. Auxiliary machinery includes Caterpillar C18 350ekW and C9 150ekW gensets. Performance figures for the Lloyd’s Register-classed vessels include bollard pull in excess of 85 tonnes and free running speed (ahead) 13.9kn.

Deck machinery specifications reflect the demanding role for the series with pride of place taken by a Markey Model DESF-48-400HP escort winch forward. Powered by a 400hp, water-cooled, continuous duty electric motor the two-speed winch delivers a pull of 191t at 8m/min in first gear and 44t at 35m/min in second gear, brake capacity is 250t. The main element of the drum accommodates 200m of 80mm towline with 50m on the working part.

The aforementioned A-staple is engineered to a design load of 400t and a set of 350mm retractable Karmoy escort tow pins are fitted forward for escort transit mode. To keep the main working deck forward clear, anchoring arrangements are provided aft and given the demanding conditions the fendering arrangements are particularly robust.

Five MLC-compliant cabins are provided on the lower deck for eight persons including an office that can be used as a spare cabin on the main deck. The usual mess, galley and domestic facilities are also included on the main deck and the wheelhouse features a single Alphatron control console with winch operator position, visibility to the forward working deck is described as ‘exceptional’

By Peter Barker