The 555-seat A380 Airbus is the newest and largest aircraft to be built by the company and due to fly for the first time in 2006.

Early in the planning process a decision was made to transport many of the major assemblies including the wings, from Airbus factories around Europe to France for assembly, by sea and river.

Wings produced at the Broughton factory for all other programmes are flown to the aircraft final assembly plants in Toulouse and Hamburg using specially designed aircraft but the wings for this new generation of aircraft are too large to be carried by aircraft.

Considerable thought was therefore required to establish a safe and reliable means of transportation from the factory to Mostyn using the shallow river Dee, known for its constantly changing tidal and riverbed conditions, low bridges and environmentally sensitive areas.

Afon Dyfrdwy (River Dee in Welsh) was designed and built by Merseyside shipbuilder McTay Marine Ltd for the Holyhead Transportation Company Ltd (an associate of Holyhead Towing) with intense collaboration from the operators and client.

The resulting vessel is a highly manoeuvrable, shallow draft, motor barge capable of transporting a single wing on its supporting jig for the 18 mile journey downstream to the Port of Mostyn from the Load Out Facility at Broughton.

Satisfying the various environmental constraints imposed by the relevant authorities and regulators for the navigation of this environmentally sensitive waterway and meeting the Airbus 'Statement of Requirements' for carrying the wings tested the ingenuity of the design team.

Among the marine requirements were; a draft not exceeding 1.50m, an air-draft of less than 4.30m and a minimum speed of 9.0 knots. The craft must be able maintain its position in a current of 4 knots and wind of force Beaufort 6 from any direction, and vessel's wash must not exceed 300mm height at 40m from the vessel (ie, the river bank). In an emergency Afon Dyfrdwy must be capable of stopping from full-speed within one ships length and was required to meet a two-compartment damage stability standard. Noise levels at 25m from the side of the vessel, underway at 8 knots, must not exceed 68dBA. No discharges into the river are permissible. The criteria to be met to carry and load wings included; the ability to load the wing via a stern ramp onto a deck capable of handling a 220 tonne rolling load. A loading ramp gradient not exceeding 1:19.1 was required and the cargo deck had to meet a flatness tolerance of +/-10mm. The cargo lift system must likewise remain within a tolerance of +/-10mm on all six lifting points.

After a long design period and a spell of testing at the Vienna Test Tank, construction commenced in spring 2003 and delivery took place in February of this year.

Afon Dyfrdwy is a vessel of 57.80m in length overall, with a breadth of 14.80m, depth of 2.60m, and measuring 235dwt. The craft 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.

One of the most interesting features of the vessel is the unusual hull-form. In order to meet the stringent requirements for wash reduction and speed, what has been described as a 'canoe type' hull-form was adopted to give a low resistance and low wash performance - combined with a large cargo deck area. The result is a mini 'Aircraft Carrier' configuration with a flat-bottomed hull and flared overhang to deck level.

Hull construction is immensely strong, with frame spacing of 550mm and 'egg-box' construction throughout the bottom. This enables the vessel to be loaded whilst aground at grillages provided at the loading facilities at Broughton and Mostyn.

Afon Dyfrdwy has a low-profile wheelhouse close to the bow and four cabins, a galley/ mess-room, and washroom facilities below decks in the forepart of the vessel. Engine rooms, situated fore and aft, are accessed from the deck and the remaining under deck space is dedicated to water ballast tanks, a fuel tank and void spaces. A small foredeck accommodates an anchor windlass to handle the two 1.5 tonne 'high holding power' anchors housed beneath the overhanging bow, and the usual mooring equipment. Two further anchors of the same type are positioned at the stern, on either side of the loading ramp opening. Each anchor is handled by a combined anchor windlass and mooring winch. Both winches are fitted with a single drum carrying a length of high performance HMPE manmade fibre rope used during the 'stern-on' mooring procedure.

Both winches and anchor windlasses were manufactured by North Sea Winches Ltd.

The vessel is propelled by four, Jastram 'water-jet', thrusters, each capable of delivering it's thrust through a full 360º. Two size W20 units located in the bow are driven by Cummins 6-CTA diesels each producing 199kW @ 1800rpm, Two larger, size W60 units, are installed in large skegs beneath the stern. Each of the latter is powered by a Cummins KTA 19 M3 engine developing 477kW @ 1800rpm.

A computerised Jastram 'Quadro-Jet' control system, with three stations located on the main wheelhouse console and bridge wings, is used to control the power and direction of thrust from all four propulsion units - in unison or individually. An autopilot can be used to control the aft units on passage.

Each main engine is located in its own engineroom and cooled by means of self-contained Bloksma box coolers. The engines are started locally but controlled, monitored and stopped from the bridge. Electrical power for the vessel's systems is supplied by two Stamford alternators, with a capacity of 80kW, powered by Cummins 6BT 5.9 diesels. A further Deutz B/FL 1011F, air-cooled harbour set is rated at 33kW.

The full width wheelhouse gives the vessel's master excellent all round vision, including aft over the cargo deck. A full outfit of propulsion controls, navigational and communications equipment is located on the main full-width console, with essential items duplicated on the bridge wings. Navigational equipment, mainly from Furuno, includes a high-definition daylight river radar, a 15in clear view radar, an echosounder, a GP2 WAAS Navigator, and a NX-500 Navtex receiver. The auto-pilot is a Robertson AP9 Mk3, taking input from the S.G.Brown - Minerva gyro compass. In order to deal effectively with the local marine conditions two Leica DGPS systems are installed, one incorporating Real Time Kinematic RTK GPS input. A purpose designed charting and tidal prediction computer system is used giving the vessel's master real time information on the route and tidal conditions. Inputs are also available, remotely, from tide gauges on the route between Mostyn and Broughton.

Panels in the wheelhouse also enable draft monitoring and ballast control to be carried out centrally under remote control from the wheelhouse. The rapid transfer of ballast is facilitated by two 180 tonne/hour Desmi pumps which, with their associated ballast valve system is controlled by a purpose built panel and system from Dobbie McInnes. A closed circuit television with cameras mounted around the vessel give improved visibility where necessary but also carry out the important function of recording washpatterns to confirm that the vessel meets environmental conditions for wash-reduction.

The large after deck carries a single Airbus 380 wing on a sophisticated, high precision, jig that is handled in much the same way as a very large pallet by an equally sophisticated 96-wheel low profile 'Multi-Purpose Vehicle' (MPV). Each wing is approximately 45m in length, 12m wide and weighs around 30 tonnes. The jig has six supporting legs, 1m high, and adds another