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May 2005 23 The Afon Dyfrdwy: Wings Under the Bridge Low bridges continue to challenge and limit trans- portation on inland waterways. Recently Hollyhead Towing of North Wales U.K. developed a self powered vessel, Afon Dyfrdwy, to transport the prefabricated wings for the new Airbus A380 from the manufacturer at Broughton, near Chester, down the River Dee (Afon Dyfrdwy is the proper Welsh name for the River Dee). Components of the aircraft are built at various loca- tions for final assembly at Toulouse, France. After being moved one at a time down the river to Mostyn Dock the 150.9 x 39.3 ft. (46 x 12-m), 200-ton wings are transhipped on an ocean going vessel for final delivery. The river trip requires the 189 x 48.5 ft. (57.6 x 14.8- m) boat to pass under low bridges. To meet these restrictions while transporting its cargo, the boat was built at McTay Marine Ltd. Bromborough, U.K., with a 9-ft. (2.8-m) molded hull depth and a sophisticated ballasting system capable of taking the draft down to 4.9 ft. (1.5 m) with a 14.1 ft. (4.3-m) air draft. The bal- last system can vary the boat's trim to allow for differ- ing weight distribution between the port and starboard aircraft wings. In addition to the ballast system, the boat is equipped with a low level cargo deck with 300 ton capacity lift system. The allows a specially designed trailer to roll on with the wing. The lift sys- tem then raises the wing on its pallet allowing the trail- er to be rolled off the vessel and the wing to be lowered to the deck. Heavy steel rails above the bulwarks assure that the wing will not be damaged in the event that the boat did come in contact with an overhead obstruction. At the same time attention is paid to mon- itoring the river depth and bottom contours with an echo-sounder with an electronic survey and route plan- ning navigation system. Propulsive power for the boat is provided by two Cummins KTA 19 M3 engines, 477kw each driving a pair of Type W60 Jastram azimuthing jet thrusters. These take water from the hull sides just at the chine and expel it out the bottom of the boat. Controllable vanes can direct it in any direction. Not only does this give the operator a very high level of control over the vessel's movement, it also protects the river bottom from the type of disturbance that con- ventional propellers could create. Environmental requirements stipulate that river silt may not be dis- turbed and the vessel wake must be kept to less than 30 cm in height. The main engine thrusters are located aft. An additional pair of Jastram W20 bow thrusters, each driven by a Cummins 6CTA8.3, give the operator an additional level of control and redundancy. The boat is classed, A1 IWW 'Roll on Roll off barge', LS "0", Zone 1, `River Dee Service`, + LMC UMS, E.P., A, B. UK MCA Class IX A. Circle 17 on Reader Service Card In October 2004, the contract was signed between Gulf Cobla and Damen Shipyards Gorinchem for the delivery of a Damen Multi Cat 1908. The Multi Cat is amongst other duties intended to assist the Khaleej Bay. This Damen Cutter Suction Dredger 600 was built at Abu Dhabi Shipbuilding from a partial pack- age of Damen Technical Cooperation. The dredger has a suction pipe diameter of 600 mm, a cutter power of 920 kW and a dredge pump of 1910 kW. As the hull of the Damen Multi Cat 1908, named Tarpon Bay, was on stock a short delivery time could be offered. The crane was delivered in the last week before the delivery of the vessel, but through careful planning and preparations the vessel could be handed over on time in March 2005. The Damen Multi Cat 1908 is one of the larger sized standard Damen Multi Cats with the following main dimensions: Length o.a.: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61.3 ft. (18.7 m) Beam o.a.: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26.2 ft. (8 m) Depth at sides: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9/1 ft. (2.8 m) Draft: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.5 ft. (2.3 m) The major tank capacities are: Fuel oil (own use): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.5 cu. m. Fuel oil cargo: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46.6 cu. m. Fresh water (own use): . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.6 cu. m. Cargo fresh water: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14.8 cu. m. Ballast water: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10.5 cu. m. The Damen Multi Cat 1908 has a single chine hull with a transom stern and a mildly-formed bow. The hull is divided into five watertight compartments and is of a very strong construction with side and bottom plating of 10 mm and deck generally of 10 mm thick- ness and even 20 mm thickness in the area aft of the bow roller. The two push bows are fitted with cylin- drical rubber fender of 380 mm diameter. Two Caterpillar 3408C TA engines are driving fixed pitch propellers of 1300 mm diameter, through Reintjes WAF 164L reverse/reduction gearboxes. This complete installation is of standard proven design resulting in a guaranteed trouble free opera- tion. The 1300 mm diameter propellers run in Van de Giessen nozzles which have stainless steel inner rings. The total power is 716 bkW (960 bhp) at 1800 rpm. This propulsion installation resulted in a trial speed of 8.9 knots and a bollard pull of 12.5 tons. The most important tool of the 'Tarpon Bay' is the hydraulic deck crane. This crane is of the knuckle boom configuration; make Effer type 65000-3S. The capacity is 7.6 ton at the maximum outreach of 25.7 ft. (8.34 m). The crane is complete with a hydraulic winch with a lifting capacity of four tons. A main engine driven hydraulic pump supplies the power for the crane. The wheelhouse is fitted out with a helmsman's seat, a chart table with chair and completed with time clock, barometers, binoculars etc. The communica- tion and navigation equipment consists of a Sailor RT2048 VHF radio, a Furuno LS-6100 echo sounder, a Furuno FR-7062 radar and a Furuno GP-1650 GPS/chart plotter. This chart plotter has a six-in. dis- play and is delivered with a digital chart card of the operating area of the 'Tarpon Bay'. Circle 18 on Reader Service Card Damen Delivers Multi Cat MR MAY 2005 #3 (17-24).qxd 5/2/2005 6:53 PM Page 7
