'Afon Cadnant - The Most Impressive Tug Yet for Holyhead Towing

The new 'Afon Cadnant' is one of a pair of tugs of a completely new class that truly represents the development that has taken place in the tug fleet and in the company as a whole. In keeping with the previous generation of tugs, the 'Afon Alaw' class, the new vessels will be capable not only of unrestricted deep sea operation but are fully equipped to provide a wide range of services on site.

Afon Cadnant is a triple screw, shallow draft anchor handling tug, built to Ice Class and fire fighting FiFi 1 standards and compliant with the class requirements of Lloyds +100A1 Tug LMC UMS, Ice Class 1B, FiFi 1.

This first vessel of the new class has been constructed by Metaaldraaierij Sepers BV in the Netherlands to a design conceived by Holyhead Towing technical staff and managing director Captain Mark Meade in collaboration with Dutch consultants Technisch Bureau Gommes. The resulting vessel is 35m in length overall, with a beam of 11.5m (both excluding fenders), a depth of 4.0m, a minimum working draft of 2.4m and a maximum mean draft of 3.15m.

The single chine hull, much favoured by Holyhead Towing, was chosen to provide adequate buoyancy for lifting and anchor handling and the hull form allows the vessel to take the ground comfortably without damage. A high forecastle affords good protection at sea and incorporates a substantial push knee in the bow. Additional, heavily fendered rubbing strakes are fitted on either side of the forecastle to supplement the moulded rubber belting used around the hull at deck level. The aft bulwarks are well shaped to leave an open stern accommodating a 50 ton SWL stern roller of 700mm diameter and 4.5m wide. The work deck has standard ISO fastening for the carriage of containers and the usual timber protection.

Internal tanks enable 218m3 (183 tons when full) of fuel to be accommodated, along with 135m3 of fresh water, 24m3 of sewage, 2.6m3 of dirty oil and 2.6m3 of lubricating oil.

Three Cummins KTA50-M2 main engines power Afon Cadnant's triple screw propulsion system. The engines deliver a total of 5,100 bhp at 1,800 rpm to drive fixed pitch propellers via reverse reduction gearboxes. Kort propulsion supplied the propellers, their associated fixed nozzles and a hydraulically powered bow thrust unit delivering 2.5 tons of thrust. Four quick acting, semi-balanced, high stall, rudders are fitted, each with a 60(DEGREE) hard-over angle. Two rudders are located adjacent to the centre propeller and one each on the centreline of each of the outer screws. This propulsion system is designed to produce a bollard pull of 54 tons, a free running speed of 12 knots and extremely good manoeuvrability.

Auxiliary electrical and hydraulic power aboard Afon Cadnant is of prime importance and is provided by four more Cummins diesels. Two 83kW (105kVA) alternators, powered by Cummins 6BT 5.9-D(M) engines located between the main engines, supply electrical power for the vessel. A pair of Cummins N14-M diesels, rated at 480 bhp each and positioned side by side ahead of the centre main engine, provide power for the hydraulic power pack. The latter are arranged to work in tandem or separately and the power pack, manufactured by North Sea Winches, supplies hydraulic power to the bow thruster, winches, crane and other deck equipment.

Also located in the engine room are a sewage treatment plant, fresh water plant and high capacity fresh water and fuel transfer pumps. High capacity box coolers are installed to provide cooling for all main and auxiliary machinery.

Pumps to supply water to the FiFi 1 external fire fighting system are coupled to the outer main engines. This arrangement enables the centre main engine to be used at full power if required to manoeuvre the tug during fire fighting operations. Two monitors, each with a capacity of 1,200m3 per hour, are mounted at the forward end of the bridge deck.

At the heart of the tug's deck equipment is a double drum, reverse waterfall type towing and anchor handling winch. Again, in keeping with many previous Holyhead newbuildings, the winch and its associated hydraulic system and controls was designed and built by North Sea Winches Ltd. The winch has a maximum line pull of 50 tons at 8m/minute and a brake holding capacity of 140 tons. The towing drum can accommodate 550m of 52mm diameter steel wire rope and the anchor handling drum can hold up to 380m of 48mm wire. Manually operated spooling gear is used in conjunction with both drums. The spacing of the spooling gear guide rollers is controlled hydraulically by the operator and enables shackles, pennants or larger ropes to pass easily under full control. Both the main towing and anchor handling winch and tugger winch can be controlled locally or from the wheelhouse.

North Sea Winches also supplied a tugger winch and storage drum for spare towing gear. The tugger winch, mounted on the port side adjacent to the main winch, has a line pull of 9 tons at 20m/minute, can take 120m of 22mm diameter wire and operates through a four roller fairlead. Located in an under deck hold for spare gear, the hydraulically operated storage drum has the capacity to hold one complete 550m towline. The same manufacturer supplied the anchor windlass, to handle the 28mm U3 chain and 900kg (oversize) Pool, high holding power anchors.

Dutch style 'bitts' and a quick release 60 tons SWL towhook are provided aft of the towing winch. A set of three hydraulically operated tow pins with a hold down hook were manufactured by Western Machinery Works in Canada and located on the centreline forward of the stern roller.

The all important deck crane is a hydraulically operated HS Marine Crane AKC rated at 185 tons per metre. With a long arm telescopic jib, the crane typically has working capacities of 32,540kg at 4m radius through to 6,350kg at 17m radius. A 6 ton winch wire and hook are included and the crane can be operated remotely if required.

Afon Cadnant has extensive fully air conditioned accommodation for up to 18 persons in ten cabins. All of the cabins are located in the forecastle and include two single cabins with en suite facilities and eight doubles. Located in the superstructure is a large mess room and adjacent galley, a laundry, changing area and the ship's office. Extensive use has been made of modern acoustic and thermal linings and insulation to reduce noise levels throughout the accommodation and assist in maintaining reasonable temperatures in a vessel required to work in conditions from +40 to -20 degrees C.

The spacious wheelhouse follows the same style as earlier vessels, with good visibility from four control positions. Two positions are located on the centreline and equipped with Captain's chairs. The forward control position gives ready access to all of the major propulsion, navigational and communications equipment and includes a number of multi-function display screens. From the aft position the master has an exceptional view of the working deck and winches with duplicate controls to hand for propulsion and winches, essential navigational equipment and radios.

Afon Cadnant has a communications outfit that meets the requirements of GMDSS Area 3 and includes two Furuno Felcom 15 Inmarsat C systems, a Furuno FS 1570 DSC radiotelephone, two Furuno FM 8800 class A DSC VHF radios, four VHF handsets, EPIRB and SART. An Irridium IMF 1000 satellite telephone with a data option and email capability is also installed, along with a Furuno LH 3000 hailer intercom system, a cell phone and a Thuraya DSL satellite broadband modem for computers in the ship's office and wheelhouse.

Furuno also supplied much of the navigational equipment package, that includes a Furuno FR1510 MK 111 15" radar, FC50 GPS compass, GP90 GPS, FE700 echosounder, DS80 doppler log, FA150 AIS system, NX500 Navtex and a Furuno Navnet radar with internal cameras and video system. A Robertson AP50 automatic pilot is installed, in addition to a magnetic compass and chart plotter.

This latest addition to the Holyhead Towing fleet was launched at the Sepers Druemel yard in the spring by means of a submersible pontoon provided by Van der Wees Transport of Dordrecht. After extensive commissioning and trials Afon Cadnant was due to sail on its first assignment early in September.

The second tug of the pair, to be named 'Afon Cymyran', is being completed at the Humberside UK yard of Hepworth Shipbuilders, one of the few yards still open for business in the small craft sector. Hepworth and Holyhead Towing have had a long association and the majority of the towage company's purpose built vessels have originated from this yard. The hull of the second tug was sub-contracted to Aveco in Middlesborough and towed to the Humber in June. Work started almost immediately and delivery in March 2008 is anticipated.

The introduction of Afon Cadnant and its sister ship is by no means the end of the Holyhead newbuilding programme. A number of other vessels are under consideration or on order including a standard design Neptune multi-purpose pontoon type work vessel and a wind farm access catamaran. The Holyhead fleet now comprises some 20 vessels of all types, ranging from high specification multi-purpose tugs to smaller workboats, survey craft and several other specialised vessels. Many of these vessels are currently employed in locations abroad such as the Caspian Sea, West Africa, the Persian Gulf, Russia and in various locations around Britain and Europe.