Damen is building the ASD Tug 2009 for commercial use

It was designed initially to meet the requirement for four such tugs as part of the massive 29 vessel ‘package’ built for the Serco support contract with the Royal Navy at HM Naval Bases in Portsmouth, Devonport and the Clyde (Maritime Journal December 2009 & April 2010).

Sixteen tugs and tug/workboats were included in the ‘package’ and four were 20m ASD tugs built to a bespoke design formulated to meet the exacting needs of the client. The first vessel, SD Eileen, was delivered in April 2010 and the remaining trio , SD Christina, SD Suzanne and SD Deborah, by the end of the year.

In spite of the tight specification, which required a mass of equipment to be embodied in such a small vessel for naval purposes, the resulting tug proved to be extremely successful in service. At the time it seemed unlikely that the ASD Tug 2009 would prove to be a serious commercial proposition but market research indicated otherwise and Damen are now able to offer a ‘cost effective’ variant as part of their ASD range. Two tugs are already under construction at the Damen Changde shipyard in China, with delivery due in the summer of 2012.

In overall appearance, the new ASD Tug 2009 has changed little, with the hull measuring just 21.19m in length overall, with a maximum beam of 9.43m, a depth (at sides) of 4.00m and a slightly increased draft of 3.90m. The double-chine hull form is similar to other Damen ASD designs and includes a short box keel, a docking skeg aft and a stern optimised for good performance when running astern. A broad beam enhances stability and the bulwark design and fendering gives adequate clearance and protection above and below the waterline. The tug complies with Lloyds Register rules for 100 A1 Tug Specified Coastal Service + LMC UMS and *IWS.

A bollard pull of over 27 tons is anticipated towing ahead and 25.2 tons astern, with a maximum speed of 11 knots. The most significant change from the naval version is that the new ASD Tug 2009 will have a Schottel propulsion system comprising two SRP 550 FP (895 kW each) fully azimuthing propulsion units powered by Cummins KTA 38-M2 engines generating a total of 2,400 bhp (1,750 bkW) at 1,800 rpm. The propulsion units incorporate 1,750mm diameter fixed pitch propellers, rotating in high performance thrust enhancing nozzles.

The supply of Schottel units for this Damen project is significant for both companies. A contract was signed at the Europort shipping fair in Rotterdam on 10 November 2011, marking the beginning of a new chapter in the propulsion specialist’s long success story in the field of tug propulsion. Damen’s purchasing director Cees van Dijk and Coen Boudesteijn (product director, Tugs and Workboats) explained their decision for Schottel, saying “The selected propulsion systems fully satisfy the technical requirements for this new tug type, and Schottel is also in an excellent position to provide after-sales service worldwide.”

Electrical power is supplied by two Cummins 6B-CP auxiliary generators, each rated 88.8kVA at 230-440 volts, 50Hz. Double hydraulic pumps driven by both main engines power the deck hydraulics system.

The deck layout is spacious, with adequate room to work around the towing winches, which are installed fore and aft to enable quick and effective towing connections to be made when working with ships, barges and other floating plant. Both winches are hydraulically powered and supplied by Kraaijeveld. The winch mounted on the foredeck incorporates a cable lifter for the vessel’s single anchor and a towing drum with a line pull of 10 tons and a maximum brake load of 75 tons. An almost identical winch is fitted immediately aft of the deckhouse in a particularly neat installation. Both winches are used in conjunction with substantial, stainless steel lined, towing fairleads and high performance manmade fibre ropes. A Mampaey quick release tow hook with a safe working load of 450 kN is also fitted aft for secondary use.

The outfit of equipment on the after deck is completed with the provision of a Heila HLM 20-3S hydraulically powered marine crane with a maximum lifting capacity of 1.7 tons at a maximum outreach of 10.56m.

A neat, well designed superstructure, wheelhouse and accommodation makes the maximum use of the space available, while at the same time offering the tugmaster excellent all round vision. Accommodation is provided for up to five persons, in one single and two double berth cabins. Durable modern linings, an acoustical Dampa ceiling in the wheelhouse, Bolidt floating floors along with flexibly mounted engines and coupling have all contributed to reducing noise levels throughout the wheelhouse and accommodation.