Marine Link
Saturday, January 20, 2018

Same operator ... different solutions

During 1996, three Aquamaster and two Voith type tugs are to be delivered to Howard Smith Towage & Salvage from Dutch and U.K. yards in a $27-million U.K. expansion program boosting services at the ports of Southampton and Felixstowe, and on the rivers Medway and Humber. So far, three vessels have been delivered representing the two designs; both of which incorporate new features derived from the owner's extensive experience operating more than 130 tugs worldwide.

Southampton's new vessel, Lyndhurst, was the first to arrive. Built at the McTay Marine yard on Merseyside, this 98.4 x 36.1-ft. (30 x 11- m), Voith Schneider propelled, Ruston diesel powered tractor tug follows five similarly configured vessels built by the yard for the same operator in 1990/91. An evolutionary process can, however, be detected. The most obvious visual change is a much higher sheer at the stern, designed to prevent the aft deck becoming awash when running astern at speed in escort mode. The aft fendering has also been dramatically improved and better wheelhouse visibility accomplished by modifying the layout and removing horizontal window bars.

Power is provided by a pair of 1,500-kW Ruston 6RK 270 main engines, thus extending a close relationship between engine builder and operator. This current spate of newbuilds will bring the number of Ruston diesel equipped tugs in Howard Smith's fleet to 44. Each main engine has a Norgear step-up gearbox fitted to its free-end driving hydraulic systems for all the deck machinery, and a pair of Worthington fire pumps. The Rustons are also fitted with alternators to charge the batteries; part of another improvement to allow the vessel, if necessary, to remain fully operational without power from the generator sets. Located in their conventional 'tractor' position forward are the Voith Schneider 28GH/200 propulsion units. On trials, Lyndhurst achieved a maximum bollard pull of 45.3 tons and a free running speed of 12.5 knots — both in excess of contract requirements. Howard Smith Towage insists that crew accommodation should be above main deck level and all the cooking, dining and sleeping facilities are contained within the deckhouse. Two single and two double cabins are provided together with separate galley and messroom. The high, compact wheelhouse has become a characteristic feature of Howard Smith tugs as well as many built by McTay for other customers. It has an almost spartan but fundamentally functional interior, with a small floor area which contributes to the visibility. In order to see what is happening below, the skipper does not have to move from their position across to a window. The command console is straightforward, and it only houses the essential thruster, engine and winch controls. All other wheelhouse items are located either in a four-sided overhead console or adjacent to the chart table.

A different solution has been selected for the growing Port of Felixstowe fleet, with the recent arrival of Melton and Bentley, identical Aquamaster azimuthing stern thruster tugs. Before settling on this option, Howard Smith's Felixstowe operation 'borrowed' a Voith tractor and also a powerful stern drive tug from the company's own Humber and Medway fleets, and employed these vessels in practical trials, docking ships that regularly use the port.

According to Director Ken Marshall, the local requirement of high speed on and off the berth made the stern thruster option the preferred choice of all involved in the evaluation trials.

Once the decision was made, yards worldwide were invited to submit proposals, but the final short list comprised Dutch, Spanish and U.K. yards. Damen, famed for its range of standard designs, offered a 107.4 x 39.2-ft. (32.7 x 12-m) hull with a draft of 15 ft. (4.60 m). The Howard Smith design team then suggested modifications to improve speed and astern running. The builder agreed to carry these out, and a contract was signed for three tugs, a third identical tug being required for the Medway.

Maintaining faith with the same engine builder, each tug is powered by a pair of 1,800-kW Ruston 6RK 270m diesels.

These drive Aquamaster US 2001/3325 azimuthing units through Twin Disc 3000.5 HD marine control drive clutches, as Mr. Marshall explained: " ... to ensure the level of precision maneuvering necessary for the Felixstowe operation." On trials, the vessels reportedly achieved free running speeds of 13.5 knots and bollard pulls in excess of 60 tons.

As on Lyndhurst, all the living quarters on Melton and Bentley are above the main deck level. The chief engineer and two crew members each have individual cabins on the lower level of the deckhouse adjacent to the mess room and galley, and the captain is accommodated one deck up immediately beneath the wheelhouse. This also follows the established pattern of the Southampton tug with full height windows and small floor area. In response to requests from Howard Smith's engineers, Aquamaster has developed an improved control system to facilitate close-quarter maneuvering.

Called the 'Aquaduo' it comprises three modular panels compact enough to be located side-by-side within easy arm's reach; with dual steering levers, dual speed control levers and a small steering wheel between them.

Interest shown in all the new tugs has been high and already the Aquamaster versions would appear to have set a standard, as the vessels ordered by U.K. operator Cory for Milford Haven bear a remarkable similarity. At the time o{ MR/ENs visits to Southampton and Felixstowe, Damen and McTay each had one more tug to deliver to Howard Smith.

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