Arun-class lifeboat

The Arun class lifeboat is a fast all-weather lifeboat designed by the Royal National Lifeboat Institution (RNLI) for service at its stations around the coasts of Great Britain and Ireland. They were operated by the RNLI between 1971 and 2008. Many have been sold to see further service in the lifeboat and coastguard services of other countries.

The class takes its name from the River Arun in Sussex, England.

History
The RNLI's first lifeboat capable of speeds in excess of 10 kn was the 14 kn Waveney-class introduced in 1967. This was based on an American design, but in 1971 it was replaced by the Arun-class which was designed by the RNLI and gave vastly improved accommodation and increased the speed to 18.5 kn.

The first prototype boat entered service at St Peter Port in 1972 but moved on to Barry Dock where it was stationed until 1997. Two more boats were introduced in 1973 and 1974 and then full production started in 1975 although small numbers of Waveneys were still built until 1982. By 1990 46 Arun-Class boats had been launched. The following year saw the launch of the first 25 kn Severn and Trent class boats.

The three prototype boats were withdrawn in 1994–1997, the third of which then went on display at the National Lifeboat Museum. The production series boats were taken out of regular service between 1998 and 2007. While a few have found new uses around the coast of Great Britain, the majority have been sold to other lifeboat operators around the world, predominantly in China, Finland and Iceland and some further boats were built new for service in Canada and Greece. Those travelling long distances go as deck cargo on larger ships but those going to closer harbours are generally sailed across under their own power. The first boat to go to Iceland, the Richard Evans, was loaded as deck cargo on a container ship but was washed overboard during the passage – the only Arun to have been lost at sea.

Design
The design was developed for the RNLI by J.A. MacLachlan working for naval architects G.L. Watson of Glasgow. Initially proposed with 'chines' along the hull to disperse the spray and improve stability when underway at speed, this caused a high deck above water which proved difficult when trying to get people aboard from the water, so the chines were dispensed with on the second boat and the deck curved down nearer the water. The three prototypes were built with wooden hulls and were respectively 51 ft, 52 ft and 54 ft long. The next four boats were 54 ft long with glass reinforced plastic (GRP) hulls but the remainder were 52 ft long. These all had GRP hulls except for one built in 1986 with a steel hull. It was regarded as the best of the class for seakeeping, although the slowest. The GRP hulls were moulded in blue material in the outer skin. After a while it was found that water was accumulating in the fibreglass which added up to 2 tons to the weight. The boats had the coloured layer stripped off and replaced by a new one made with clear gel which reduced the amount of water absorbed.

The large watertight cabin gave it self-righting capability. Two survivor cabins are situated below decks where first aid and emergency equipment is stowed. The hull is divided into 26 watertight compartments as protection against sinking should it be holed. There is also a flying bridge above the main cabin with an auxiliary steering position which can be used when additional height or visibility is required during an operation. The boat won a Design Council award in 1982.

Two Caterpillar D343 460 hp diesel engines are fitted to earlier boats although many of the later boats are fitted with two Caterpillar 3408TA 485 hp. Fuel tanks have 620 gallon capacity which gives an operating range of 250 nmi.

RNLI fleet
'ON' is the RNLI's sequential Official Number; 'Op. No.' is the operational number painted onto the boat.

Canada
Ten 15.77 m boats were built for the Canadian Coast Guard. They were all built in Canada by Industrie Raymond Ltée, Sept-Iles QC; East Isle Shipyard Ltd., Georgetown PE; Hike Metals & Shipbuilbing Ltd., Wheatley ON, with aluminium hulls except for the GRP-hulled British-built prototype (CCGS Bickerton) which was built by Halmatic, Southampton. They are considered "high endurance" lifeboats staffed by a crew of four. The first vessels of this class were ordered in 1990. The Canadian Coast Guard also maintains approximately three dozen smaller Cape class motor life boats. They are considered "medium endurance" lifeboats.

Greece
The Greek boats were built in Greece by MotoMarine with GRP hulls. Ten are in service with the Hellenic Cost Guard.