In November 2009 the Damen Shipyards Changde in China delivered the powerful and compact harbour tug Patriot, the first of a pair of identical tugs built for use in the Ukraine. Patriot, and sister ship Bulat completed two month later, were ordered by Tekom Leasing Ltd, the end-user of this tug is Odessa Sea Commercial Port. The tugs are the first examples of the ASD Tug 2310 design, a promising new addition to the comprehensive range of ASD tugs Damen can now offer tugowners.
The ASD Tug 2310 design is the result of careful market research and product development work carried out to find a replacement for the existing ASD Tug 2509. The aim was to produce a very compact, economically viable harbour tug, with a good performance, suitable for shiphandling in small harbours, confined dock systems and locks. Close co-operation between Damen’s T&W project office and Central Engineering and Research resulted in completely new design with the promise of a high bollard pull, excellent manoeuvrability, and considerable inherent stability. During the development stage everything possible was done to ensure that the final result would be a genuine cost effective Damen ‘standard’ design suitable for series production. Essential basic design criteria included; good visibility from the wheelhouse, good handling characteristics, safe working conditions and ease of maintenance.
All of the basic requirements were achieved by adopting a shorter but wider hull design - with an overall length of 22.73m, a maximum beam of 10.43m and a draft (aft) of 4.77m.The choice of hull-form was based on previous experience with similar ASD tugs, such as the ASD Tug 2411, and tank testing, taking it consideration the operational requirements. Important features of the new hull include a more heavily chamfered stern to improve performance sailing astern and a greater ‘sheer’ to reduce the possibility of excessive water on deck.
For a small vessel Patriot has a remarkably spacious layout. Considerable attention has been paid to providing adequate deck space and a safe working environment for the crew. A similar approach has been applied in the wheelhouse and engineroom. The attention to detail is self-evident. The entire bulwark structure is fully enclosed, simplifying maintenance and adding considerably to the strength of the vessel. Mooring bitts are situated on the inside of the bulwarks, and an enclosed filling station is located on both sides of the vessel, housing all of the major filling pipes and vents. In all other respects the decks have been kept free of any unnecessary projections likely to cause fouling or accidents. Such details give the vessel a simple but modern appearance.
A comprehensive fendering arrangement is designed to protect the tug and its tow during a wide range of shiphandling and other harbour operations. The bow fender comprises a large cylindrical rubber moulding mounted above a series of rubber block sections, offering excellent protection during push-pull operations. Hollow ‘D’ section rubber mouldings are fitted around the sides at deck level. The aft corners the additional protection of large diameter cylindrical sections.
A hydraulically powered towing winch, incorporating an anchor windlass, is installed on the foredeck for shiphandling operations. The winch has a single ‘split drum’ with a line pull of 18 tonnes at 11m/min and a maximum brake holding load of 130 tonnes.
Each section of the drum can accommodate 150m of 80mm diameter high performance Euroflex fibre towline. In normal operation only one towline will be in use and the ‘spare’ towline secured on the drum. The towlines are deployed via a ‘towing fairlead’ incorporating two apertures lined with stainless steel.
The superstructure follows established Damen practice, with heavily chamfered corners, angled exhaust stacks, and a centrally located wheelhouse to allow maximum overhead clearance when working alongside ships. Overhead clearance can be increased further if necessary, by lowering the mast. Access into the accommodation, at deck level, is via a door at the rear, in a sheltered position between the two narrow exhaust and air vent housings.
Patriot and Bulat are fitted with a single towing bollard fitted with a 65 tonne Mampaey quick release tow hook, located in that sheltered area aft,. The ASD Tug 2310 design allows for an optional towing winch to be installed in that location. That option has proved popular with previous customers using the earlier ASD Tug 2509.
The heart of the ASD Tug 2310 is its remarkably spacious engineroom. As standard the tug is powered by two Caterpillar 3512C HD/TA/C main engines each generating 1500kW at 1600 rev/min, a total of 4023 brake horsepower. The engines have electronically controlled fuel injection systems and meet the requirements of EPA Tier 2 and IMO recommendations. Resilient engine mountings and flexible couplings reduce the transmission of vibration and noise throughout the vessel. A closed circuit cooling system and box coolers are utilised eliminating the need to handle seawater in the engineroom. The large main engine exhaust silencers are mounted in the engineroom and heavily insulated to control noise and temperature.
Each main engine drives a Rolls Royce US 205 FP/Mk 1 fully steerable propulsion unit, incorporating a built in clutch and five-blade, fixed pitch propeller of 2200mm in diameter. The propellers turn in a type TK nozzle with a stainless steel liner.
Hydraulic power for the towing winch is supplied by dual pumps, one mounted on each main engine. Electrical power is generated by two Caterpillar C4.4T diesel powered alternators, each supplying 64.5 kVA, 230/400V, 50Hz. The auxiliary machinery and necessary switchboards are located in the engineroom. A third diesel auxiliary, a Caterpillar 3406E TA, drives a 1200 cu/m/hr (at 10.5 bar) capacity fire pump to supply a single water/foam fire monitor mounted forward of the wheelhouse.
Dedicated tanks within the hull structure can accommodate 60 cu/m of fuel oil, 8.0 cu/m of fresh water, 6.3 cu/m of fire fighting foam, 2.7 cu/m of lubricating oil, 1.9 cu/m of dirty oil, 2.9 cu/m of sewage and 0.8 cu/m of bilge water. Provision can be made available, as an option, for 2.9 cu/m of chemical dispersant.
The compact wheelhouse embodies many standard Damen features in a functional and ergonomically designed layout. A centrally located control position offers excellent vision all round the vessel from the captain’s chair. The standard Damen ASD control console brings all of the essential propulsion system, winch controls and UMS alarm panels within easy reach. Foot controls are provided for some of the winch and VHF radio functions. A chart table, with drawers is neatly incorporated in the layout. The wheelhouse is airconditioned and heated and the use of modern noise and vibration control measures has reduced sound levels to 67dBA.
Navigational and communications equipment meets the GMDSS Area 3 standard. Included in the outfit of bridge electronics are; a Furuno FR-1505 radar, a Simrad AP-50 Autopilot, a Furuno GP-150 GPS and a Furuno FE-700 echosounder. Communications equipment includes, VHF radios by Sailor and a Furuno AIS set and Navtex.
Accommodation on board Patriot is suitable for up to six persons. Two single cabins are situated on the main deck, along with a spacious galley, a mess room, toilet and shower room. In spite of its limited dimensions, combining the mess room and galley has provided a comfortable lounge area equipped with TV and a DVD player. Two double berth cabins and an additional sanitary space, containing a shower and toilet are located below decks.
The entire accommodation is air-conditioned ensuring that temperatures remain pleasant even under tropical conditions. The cabins are fitted out to a good but simple standard using wood and modern lining materials. Floating floors, thermal insulation and high-grade acoustic ceiling materials all contribute towards comfortable and quiet living conditions.
As the first vessel in this new class Patriot was subjected to extensive trials. At an early stage it became clear that the ASD Tug 2310 represents a major step forward. During bollard pull trials the tug exceeded expectations, pulling 47 tonnes ahead and 45.3 tonnes astern. Maximum speeds of 12.4 knots ahead and an impressive12.1 knots astern were recorded.
The trials Captain reported that he considered the tug “more than satisfactory”. Stability was very good and sailing astern proved to be very easy, thanks to the new hull design. During turning circle tests the vessel remained very dry with little water on deck. Patriot was found to be extremely manoeuvrable and ideally suited to shiphandling operations in confined spaces and narrow waterways. Conditions on board were reported to be quiet and virtually free from vibration.
Patriot and Bulat will undoubtedly prove their worth in Odessa harbour, where they will be the first tugs to be delivered by Damen to the Ukraine. Damen believe that the ASD Tug 2310 is an ideal vessel for small harbours and will open up a new market in the large number similar ports around the world.
Damen shipyards are now able to offer a range of five harbour and multipurpose ASD tugs. They range from the new ASD Tug 2310 with 47 tonnes bollard pull to the ASD Tug 3213 terminal tug with its 95 tonnes bollard pull, introduced earlier in 2009. A sixth vessel is also ‘on the drawing board’ a 125 tonnes terminal and multipurpose tug to be designated the ASD Tug 3914.