The Atlantic 21 has to be tough and reliable - the lives of survivors and crew depend on it. Claire Judd, Assistant Editor, visited the RNLI's Inshore Lifeboat Centre, Cowes, to investigate the work that goes into the construction of these rigid inflatables.

Within five minutes of the 'shout', the crew of Hunstanton lifeboat were on their way. A boardsailor. known to have been at sea for at least an hour-and-a-half. was in difficulties close to a wreck off Brancaster eight miles away and in need of urgent assistance.

As they raced to the rescue, the crew of the Atlantic 21 Spirit of America had to check their speed to prevent the rigid inflatable flying as they overtook the waves in the rough following seas.

Before long, the boardsailor was spotted close to the wreck off Brancaster by the auxiliary coastguard, but to reach him the lifeboat would have to negotiate shallow water and breaking seas over the surrounding sandbanks. Conditions were particularly difficult around the wreck itself and in the approach channel to Brancaster, and the echosounder was of no use because the water was too shallow.

Helmsman Alan Clarke brought the Atlantic 21 in slowly, the engines tilted to reduce draft. Seas to the south of the wreck were breaking heavily and despite the generally fine conditions, visibility was almost zero in the spray.

Turning north following a report that the boardsailor was now drifting to seaward, the Atlantic suddenly grounded and stuck fast just 20ft NNE of the wreck. A helicopter would take an hour to reach the casualty, and helmsman Clarke knew the boardsailor could not survive that long. They would have to continue the search.

With the three crew members stationed in her bow to reduce the draft, the Atlantic 21 was driven forward with every sea, only to ground again in each trough, gradually filling with water.

As the lifeboat cleared to deeper water, the survivor was sighted close to starboard, clinging face down to his board. The wind was a westerly near-gale, Force 7, and the tide was running east at one knot, creating very rough, short seas 8ft high which broke heavily on the sandbanks. Visibility was still almost nil.

Positioning the lifeboat just downwind of the boardsailor, the crew fought to hoist him and his sailboard into the lifeboat as he drifted alongside. He was taken straight to the beach at Brancaster and put ashore to receive immediate medical attention.

For this service, helmsman Alan Clarke received a Bronze medal.

Bronze medal certificates were awarded to crew members Gerald Wase, Victor Dade and Michael Wallace. Another life had been saved.

It is clear that the crew acted with great courage during this rescue, displaying their considerable skills as boathandlers. But credit is also due to those who designed and constructed a class of lifeboat tough enough and manoeuvrable enough to be capable of carrying out such a successful service in extremely difficult circumstances.

Before and many times since, the Atlantic 21 class has proved itself to be both effective and efficient in fulfilling its intended purpose of offering a speedy rescue capability close to shore. And it is thanks to the designers and those who construct the Atlantic 21 that crews can depend on their craft to be reliable in life-threatening situations, without fail or fuss.

Because an Atlantic 21 will be subjected to a considerable battering during its lifetime from beach recoveries and dumping surf, each boat must be extremely tough and constructed to rigorously high standards to ensure the safety of crew and survivors aboard in the worst of conditions.

Buying suitable craft off the shelf from external manufacturers has been tried in the past. However, it is considered that by having its own staff fitting out boats the Institution is able to exercise control over standards. Few other operators need craft built to the same level of sophistication and toughness as does the RNLI.

Equipping rigid inflatables with the standard fittings of an Atlantic 21 does not make commercial sense for manufacturers. But these fittings are essential features aboard lifeboats, working as they do in conditions that beckon every less well-equipped boat to safe harbour.

To ensure craft reach the high standards necessary for them to cope with the tough work ahead, Atlantic 21s are currently designed, constructed and surveyed in-house at the Inshore Lifeboat Centre, Cowes, where highly skilled men and women work together as a team to produce rigid inflatables that conform exactly to the Institution's needs.

Those working on the Atlantic 21 are well aware of what is expected of them in terms of quality of workmanship. Alan Tate, superintendent of the Inshore Lifeboat Centre, says, 'Boats built at the ILC are constructed and fitted out to an extremely high standard, and some might even say they are over-engineered, because of risk factors involved in our work compared with normal commercial requirements.' A definite sense of team spirit exists at the Inshore Lifeboat Centre, and those involved in construction of the Atlantic 21s have many years of experience between them, as well as a great deal of enthusiasm and interest for the work. Efforts are not confined to boat production alone, but also to surveying craft and to making modifications and improvements in response to feedback from stations on the coast, from divisional inspectors and after discussing and implementing their own ideas.

Alan Tate says, 'The staff at Cowes are a team of perfectionists and you'd be pushed to find a better situation than we have here where the workers believe in what they are doing and are keen to see the right answers all the time. That applies right down to the most junior level.' There's a real sense of dedication to the task to be found at the Inshore Lifeboat Centre, as I discovered when I visited Cowes to investigate just what goes into constructing an Atlantic 21 class lifeboat. As I was shown around the workshops and was explained the many individual processes, I was struck by the sense of pride that those at Cowes take in their work.

One thing that is very clear is that demarcation lines between the different roles and workshops have to be flexible. Generally, the boatbuilder is responsible for structural work on the hull and the fitter for the metalwork and fittings, but it's probably more realistic to look at the whole process as a combined effort, involving the skills of electricians, engineers and those in the rubber shop as well.

The hull of the Atlantic 21 is one of the few elements of the lifeboat that are 'imported' from an external supplier. Halmatic, experts in hull moulding, produce the glass fibre-reinforced plastic (GRP) hull from a mould designed by Institution staff. It comes supplied to the Inshore Lifeboat Centre with the permanent sections of the side deck already fitted, although the temporary middle deck, fitted for transport only, is removed on arrival, ready for the in-hull fittings.

Already built into the hull are the six watertight longitudinal compartments with their respective bow drains and drain plugs.

During the production process, this hull is passed between boat shop, fitting shop and rubber shop as each section completes its work ready for the next stage. When it leaves the boat shop for the last time, the new lifeboat will be ready for trials and, if these are completed successfully, fit for service.

Underthe authority of Dave Butler, overseer of rigid inflatables in the boat shop, and Tony Pollard, chargehand in the adjacent fitting shop, a team of one boatbuilder and one fitter see the construction and fitting out of the craft right through from the initial stages to the moment it is deemed fit for the station.

It's a process that takes anything from four to five months, depending on the amount of emergency repair work or survey work that inevitably has to take priority on occasions.

Each team is responsible for organising their own schedule and making the most efficient use of their time.

The first task - that of preparing the area under the deck of the hull - falls to the boatbuilder. Once the portable deck has been removed, the fuel tank bulkheads are fitted. The two 18-gallon stainless steel fuel tanks are installed and then surrounded with foam, after being precisely positioned to maintain the correct longitudinal centre of gravity. Two-part foam is used and then coated with waterproof paint to ensure that no water is absorbed. Six deck beams are laid in, in readiness for the console fixings.

Also laid in the hull at this stage are the fuel take-offs and the breather pipes.

Then the 3/8in marine plywood deck is replaced, access holes (for fixing of the 'roll bar' and engine bracket to the hull) are cut out, and the deck is prepared for the tubes.

Because of the pounding that the rigid inflatable will inevitably take during its lifetime, it is absolutely essential that the inflatable tubes are fastened as securely as possible to the hull, as this could be an area of weakness in the craft.

In a first step, the boatbuilder roughens a five-inch strip around the edge of the deck to encourage maximum adhesion of the glue to tubes. The boat is then passed to the rubber shop next door, where chargehand Chris Clark and her team of five women workers prepare the tubes for fixing.

Ready-constructed by Avon Inflatables of tough, grey Hypalon material, the tubes are laid out and marked up for glueing.

Hypalon is an immensely strong sandwich of nylon between two layers of neoprene and is especially suited to its purpose. The designated adhesion areas are scuffed up with emery paper and two thin coats of Bostik adhesive are applied to the hull 24 hours apart. On the third day, two thicker coats of glue are applied to the hull and two coats to the tube, which is then firmly rolled onto the deck in a semi-deflated state and left to set for two days. After a further two days, doubler strips are attached, one each side of the tube, to strengthen the bond still further and give added flexibility.

This arrangement is strong and extremely reliable, having lasted in some cases over twenty years. But if ever the inflatable tubes are in need of repair, they can simply be removed, cleaned up, patched and re-glued to the deck for further service.

The Hypalon tubes are strong enough not to require an inner tube and it takes a very sharp object indeed to snag them.

Chris Clark and her staff also design and manufacture Hypalon fittings like stabilisers for roll bars, spare prop fittings, rope stowages, first aid bags, foot holds and cleat covers, to name but a few. Once again, most of these fittings cannot be bought in off the shelf from external sources to the correct specifications needed by the lifeboat service.

All are produced to a very high standard.

While the process of attaching the tubes is taking place in the rubber shop, the team of boatbuilder, fitter and electrician are busy working together on the console.

The basic console is bought in as a moulded GRP shell, into which access apertures are cut. Then the battery shelf is glassed in and wooden reinforcing pads are added.

After the helmsman's and crew's seats, together with the knee pads and other rubber work, have been added in the rubber shop, the console returns to the fitting shop to be equipped with radio, flares, capsize lights and so on. Most of the fittings are manufactured by the fitters while the boat is being worked on in the rubber shop.

The isolating box and control panel are tested for watertightness before being fitted into the console by the electricians, together with the sealed batteries. At this stage, the hydraulic steering is also installed.

Back again in the boat shop, the finished console is screwed down onto the deck, and the team's attention turns to the roll bar, which carries the air bag for self-righting.

By this stage, the aluminium bracket for the engines has been manufactured by the fitter and bolted to the transom. The basic aluminium roll bar, made outside the centre, is fitted out in the fitting shop with port and starboard navigation light boards, radar reflector and aerial.

Just after the roll bar is added, the righting bag is attached. It is a delicate piece of equipment and prone to damage, so its attachment is delayed until the latest stage.

Finally, the boat is equipped with the deck kit, and the inversion-proofed outboard engines are bolted on.

Both 50hp Evinrude outboard engines have to be stripped down and rebuilt to ensure re-starting at the touch of a button after capsize.

In the early days, engines were meticulously sealed, and water was prevented from entering the engine by a valve on the engine cover. All that altered when the engine manufacturer made many components in the ignition system waterproof in themselves.

Chris Powell, overseer of the engineering shop, which includes within its jurisdic- tion the inversion-proofing unit, explains, 'We were able to redesign things so that water is allowed inside the hood, but we sealed elements like the carburettor air intake instead. This makes the waterproofing more reliable, in that there is no need to make sure the hood is 100% sealed or that the control cables and electrical cables are sealed in. We can treat it as an ordinary engine, work on it as an ordinary engine, but after capsize it will still work. It makes servicing much easier.' One man takes one week to inversion- proof one engine. Four men work full-time in the unit and engines are usually worked on in batches of six. By the time the engine has been waterproofed, it will have cost the Institution twice its original price.

The process has been developed in-house over the years by trial and error.

Chris Powell says, '99% of it is down to the chaps on the shop floor who have looked at the problems, designed and made up possible solutions, tried them at sea and amended them again till the perfect solution is found.

'Hopefully, our latest system will remain virtually unchanged for the manufacturer's model changes for 1992 and 1993.

'We're very satisfied with the way the engines are currently performing, although, of course, we are always looking to refine the engine in the light of problems on the coast.' Once fully kitted-out, every Atlantic 21 is weighed (average weight: 2,8001b) and its longitudinal centre of gravity is tested. Uneven weight distribution substantially affects the performance of the boat, making its ride uncomfortable, slowing it down or causing it to take longer to accelerate onto the 'plane', that is, to lift partly out of the water to reach high speeds.

Each new inflatable is also tested for reliability and to prove it is up to the standards required for service. The compass is adjusted, the electronics are all tested and the boat is run over a measured mile to determine her speed. Finally, she is subjected to an acceptance trial and, if all is well, accepted for active service.

Throughout its life, the Atlantic 21 has developed to the point that some would argue it is currently the Institution's most efficient and cost-effective craft. Since its introduction to the fleet in 1972, it has been launched on 13,015 services, saving 4,090 lives. In 1990, there were 45 Atlantic 21s stationed around the coast.

Five Atlantic 21 s were completed in 1990, The isolating box, as well as the control panel and the batteries, are made watertight and tested before being fitted into the console by the electricians.

Photo Bob Kennovin.

four were built in 1991, and there are plans for another five in 1992. By 1996, the fleet is expected to include 77 of this class.

Development work on the Atlantics continues and Alan Tate expects that production of a new Atlantic 22 class will begin towards the end of 1992.

'We have learned so much from the Atlantic 21 class and have now bolted on so many extras that it was time to re-design the boat, particularly the console. The new lifeboat will be basically the same but a little larger and giving the crew more protection.

'We see this boat as the way forward.

The Atlantic 21 has been such an exciting, efficient boat and its correctness for purpose is smack on target. Some people argue that we've had this boat for nearly twenty years now and it may be time to try something new, but as yet there's nothing we have seen that can do the job as well. There's no point in change for change's sake,' he says.

Alan Tate explains that, as the workload of the Inshore Lifeboat e n t r e increases with a greater number of infl tables s°ing through the system and the introduction of D class crew training, it is possible the new Atlantic 22 and future Atlantic 21s will be constructed to the Institution's specifications by an outside manufacturer.

Alan Tate says: 'It's a consideration that's being looked at. Having said that, we have tried it before and the commercial approach has not always been up to the standards we require. Any such project would have to be discussed and carefully overseen if we went ahead.' But to date, having our own staff fit out boats to our own standards has proved the best solution.

The evolution of the Atlantic 21 Observations while sailing in the Bristol Channel in the 1960s first suggested to Rear Admiral Desmond Hoare, headmaster of Atlantic College in South Wales and member of the Royal Institution of Naval Architects, the need for a fast safety craft that could be launched quickly from a beach.

Admiral Hoare also recognised that such a craft would have to be efficient, reliable and above all tough to withstand the added abrasive effects of the shore and the surf. However, at the time, such a craft was unavailable.

With the help of his students at the College, Admiral Hoare set out to construct an inflatable boat to meet his requirements. As the craft developed, it became clear that extra measures were needed to strengthen the hull. Marine ply was attached to the underside of the hull to reduce abrasion and deck boards were inserted inside the craft to stiffen the hull.

Before long, a 17ft 'rigid inflatable' craft evolved, incorporating a rubber tube attached to a hollow, plywood hull with a single outboard engine at the stern. Early trials suggested that the design worked well.

A member of the RNLI's Committee of Management, Admiral Hoare subsequently offered his new craft to the Institution. It was accepted, the design was developed and improved and it was not long before the first Atlantic 21 was under construction. B500 completed her trials in 1971 and came into operation at Hartlepool in 1972...

Moving On In response to feedback from crews on the coast and from those who work on the construction of the craft, the Atlantic 21 has seen many modifications and improvements since the early years. Most notable amongst the changes are the following: - Over the last 20 years, the Atlantic 21 has increased in weight from about 2,0001b (900kg) to about 3,000lb (1,360kg). Despite this, the longitudinal centre of gravity (the LCG) has remained in the same place, approximately 69in from the transom.

- The hulls of the first eight Atlantic 21s, constructed at William Osborne of Littlehampton, were built of marine plywood. But it wasn't long before this material proved to be inadequate for the working conditions. The hull has since been constructed of GRP, although the original plywood longitudinals remain the same. Internal hull framing has also been increased over the years and frames now stand at eight-inch pitch.

- The first consoles, seating three crew, were designed in-line, but they are now constructed in a delta or T shape. It became obvious very early on that a new seating arrangement would have to be developed because of problems that arose as crew strained to see where they were going in rough seas. The T-shape has proved so popular that most commercially available RIBs today incorporate this arrangement in their consoles, providing improved all-round visibility for the crew and a better view of instruments.

- The Atlantic 21 is capable of running for three hours at full speed. The individual capacities of the two stainless steel petrol fuel tanks have been increased from twelve to eighteen gallons because of the increase in boat displacement and thus fuel consumption.

- The capacity of the inflatable righting bag has increased since its introduction in 1973 to cater for the greater displacement. Although originally only one bottle was fitted as standard and only one is needed to inflate the bag during capsize, since 1985 two CO2 bottles have been fitted for safety. After righting, the bag is deflated and re-stored, and the second bottle is then available in the unlikely event of a second capsize. Thereafter, the bag is left inflated...

- Over the years, there has been only slight modification to the sponson tube. The overhang at the stern has been varied and the handles have changed from hand-laminated ones to those moulded by Avon Inflatables. Avon also manufacture the Hypalon tubes, which are subdivided into nine compartments. If one compartment is damaged, the internal baffles expand as the pressure decreases into the damaged area to retain buoyancy. It is often thought the inflatable sponson tubes will need replacing after a few years' wear and tear. In fact, the tubes often outlast the life of the hull.

In the past, slide-on tubes using a female aluminium extrusion have been tried, but these proved difficult to fit and slide into position, so the glued-on tube is now favoured.

- Although the boat lines for the shape of the hull remain unchanged, the two spray rails, which are clearly visible when looking onto the side of the boat, now follow the waterline rather than the buttock lines, as they did in the earlier craft..