Have you lost track of what boats are in the RNLI fleet? Do you get your B class confused with your D class? You are not alone With the RNLI at the forefront of technical innovation in boat design, lifeboats are constantly evolving. In 2002 we said goodbye to the last of the Brede class lifeboats. Newcomers to the fleet are the lifeboats on the Thames, the E class, and the inshore rescue hovercraft. For the lowdown on the current RNLI fleet, look no further.

ALL-WEATHER Severn class One of the two latest classes of fast afloat boat and the largest RNLI lifeboat. Severns are allocated to stations where they can lie afloat on a sheltered mooring and where their size and large survivor carrying capacity are useful. Above the wheelhouse the boats carry a small Y class inflatable, which can be launched at sea.

Length: 17m Speed: 25 knots Range: 250 miles Weight: 41 tonnes Launch: Moored afloat Construction: Fibre reinforced composite (FRC) Crew: 6 Introduced: 1995 Trent class Developed at the same time as the Severn, the Trent has a very similar hull shape but is smaller.

Trents are allocated to lifeboat stations where they can lie afloat but where there is no need for the larger Severns. Like the Severn, her propellers are protected by substantial side keels so that they can work in shallow water.

Length: 14.26m Speed: 25 knots Range: 250 miles Weight: 27.5 tonnes Launch: Moored afloat Construction: FRC Crew: 6 Introduced: 1994 Arun class TheArun has been the backbone of the afloat fleet since 1971. A small, readily launched Y class inflatable is carried on top of the wheelhouse. The bulk of the Aruns are built of glass fibre, although three ex-fleet boats were wood and there is one in the training fleet made of steel Length: 16m Speed: 18 knots Range: 230 miles Weight: 29 tonnes Launch: Moored afloat Construction: Class reinforced plastic (GRP) Crew: 6 Introduced: 1971 Tyne class The Tyne's compact superstructure is designed to fit existing boathouses and her steel hull and fully protected propellers take into account the stresses and strains of slipway work.

Length: 14.3m Speed: 17.6 knots Range: 240 miles Weight: 24-25 tonnes Launch: Slipway or afloat Construction: Steel Crew: 6 Introduced: 1990 Mersey class The Mersey was designed as a faster replacement for older carriage-launched lifeboats. The Mersey's protected propellers and relatively light weight make her suitable not only for carriage launching but also slipways and even lying afloat where size or depth of water is critical.

Length: 11.77m Speed: 17 knots Range: 140 miles Weight: 13 tonnes Launch: Carriage, afloat or slipway Construction: FRC or aluminium Crew: 6 Introduced: 1988INSHORE Atlantic 75 Slightly bigger and faster than the Atlantic 21, the Atlantic 75 provides a rapid response to inshore emergencies by day or by night. An inflatable bag on a rollbar enables them to be righted after capsize.

Length: 7.3m Speed: 32 knots Endurance: 3 hours at max. speed Weight: 1,450kg Launch: Trolley, floating boathouse, davit Construction: CRP hull with hypalon-coated nylon tube Crew: 3 Introduced: 1993 Atlantic 21 A fast and rugged rigid inflatable, first developed at Atlantic College in Wales and then by the RNLI. The forerunner of the Atlantic 75, the Atlantic 21s share the same features and are being steadily replaced by the newer boat.

Length: 6.9m Speed: 29 knots Endurance: 3 hours at max. speed Weight: 1,400kg Launch: Trolley, floating boathouse, davit Construction: GRP hull with hypalon-coated nylon tube Crew: 3 Introduced: 1972 D class The original RNLI inshore lifeboat. Fast, light and with very shallow draught, they can respond rapidly and work in very shallow and confined waters. They have a single outboard engine and can be launched from special trolleys or even manually.

Length: 4.9m Speed: 20 knots Endurance: 3 hours at max. speed Weight: 338kg Launch: Trolley Construction: Nylon coated with hypalon Crew: 2/3 Introduced: 1963 E class fast rescue boat SixT9-FRC-type boats, developed for use with waterjets, have been provided for use on the Thames.

They can operate in both daylight and darkness, and are the fastest lifeboats in the fleet. The boat has an assisted righting capability similar to the Atlantic.

Length: 9m Speed: 40 knots Endurance: 4 hours at max. speed Weight: 3,500kg Launch: Moored afloat Construction: Aluminium alloy hull + closed cell foam collar Crew: 3 Introduced: 2002 Inshore rescue hovercraft The latest addition to the RNLI fleet, the first craft was introduced at Morecambe in 2002. Fast and manoeuvrable, this amphibious craft has specialist capabilities on mud and very shallow water where no other craft in the fleet can reach. They are road transportable, powered by two VW diesel engines and can carry up to 10 people.

Length: 8.1m Speed: 30 knots Endurance: 3 hours + 10% reserve Weight: 2,400kg Launch: From most smooth surfaces Construction: Marine grade aluminium hull with FRC Crew: 2/3 Introduced: 2002This issue covers the current RNLI rescue fleet. In the next issue of the Lifeboat we look forward to finding out about other life saving equipment.

Trent class Acun class Mersey class Atlantic 75 Atlantic 21 D class Inshore rescue hovercraft © Gilbert Hampton O Peter Bentley/Royal Bank of Scotland © Rick Tomlinson/Royal Bank of Scotland © Nicholas Leach © Cotin Watson © Ian Readman © Martin Fish.