The RNLI's Shoreworks Manager Howard Richings continues his look at the Institution's shore facilities T;• he effects of coastal geology on the costs of operating the lifeboat service may not be immediately apparent, but the relative hardness of rocks and the actions of ancient and modern geological processes have all helped to form the varied and attractive coastal features which we enjoy around our coasts.

The method chosen for launching a lifeboat in a particular area is often dictated by the nature of the coastline: shallow sandy beaches requiring mobile carriage launched boats, sheltered deep water harbours allowing afloat berths and rugged exposed cliffs requiring slipway stations. Each method has its own cost implications in terms of the lifeboat and her launching equipment.

The greatest capital cost is, however, often the cost of building and, in some cases, protecting the boathouse and the launching area. The East Coast of England from Holderness to the Thames estuary is very young in geological terms and soft and glacial deposits are being rapidly eroded in places. Large quantities of shingle, silt and sand are continuously on the move with consequential implications for coastal structures.

Unique With this very much in mind we pick up the thread of our journey at the end of one of the most interesting coastal features in Europe.

Number lifeboat station is unique in a number of ways. It serves one of the busiest sea routes in Europe and the natural forces at work on the famous spit that terminates at Spurn Head, with its RNLI village and the Institution's only full time lifeboat crew, ensure that life never becomes dull for the RNLI's shoreworks staff.

The RNLI and the Number pilots share the responsibility for maintaining the four-mile road link and the essential services necessary for the seven families and the pilot station. The spit is the subject of a recently formulated management policy, which now favours letting nature take its course with regard to coastal erosion.

During the last major ice age sea levels were well below those of today and much of the bed of the North Sea was dry land. Today's sand spit lies on top of ridges of material deposited by the ice sheet, and is a mobile feature controlled by the actions of wind and tide. The successful work by Victorian engineers to maintain the integrity and position of the spit after major breaches in the 1850s, is the cause of the current instability. Similar problems could occur at any time, and the RNLI has had to install generators and water storage at a cost of over £250,000 in case of any interruption.

Precisely how the situation will progress cannot be predicted, at places the spit is now less than 30m wide and serious breaches would make operations difficult - there being no alternative location for the lifeboat station.

However, while the spit is vulnerable to erosion Spurn Head itself, where the lifeboat station and village are located, is more solidly founded and is not believed to be under any immediate threat.

In 1995 the old Humber slipway lifeboat house was demolished - the lifeboat having been kept afloat for some years - illustrating yet another 'hidden' cost of providing lifeboat stations. Such structures cannot just be abandoned, and must either be kept in a safe condition or removed.

Just across the Humber estuary lies In the Summer 1997 issue we began a circumnavigation of the coast from Berwick-upon-Tweed and stopped over at Withernsea. This section of coast is perilous and we should have been on our guard.

As a result we wrongly assigned a Tyne to Tynemouth. which actually has an Arun, which should be replaced by a new 25 knot Severn in 1999. Neither class of boat sounds as appropriate as a Tyne, but fortunately lifeboat allocation is based on sounder principles than coincidental geographical nomenclature! Cleethorpes where work is currently in hand to improve the facilities at the inshore lifeboat house.

Grimsby, a little further to the South, does not have a lifeboat station but is the second home of the Number lifeboat, which operates from this famous fishing port when weather conditions make the Spurn Head berth untenable.

In such circumstances the lifeboat may be away from her home base for several days, and so accommodation has to be provided close to the berth for the six-man crew. A new dormitory and supporting facilities were provided in 1994. It is a fortunate coincidence that while Grimsby does not offer suitable allweather berthing for the lifeboat it is safe under the very conditions which make the Number mooring difficult.

Value After the home of the fishing industry we move south past the holiday resorts of Mablethorpe and Skegness. Skegness saw the completion, in June 1990, of the first purpose-built boathouse for a carriage launched Mersey, which also houses a D class inshore lifeboat. At a cost of just over £160,000 it represented excellent value for money, and was the first new boathouse built by the RNLI for an all-weather lifeboat in over 20 years.

After carefully navigating the Wash, where sediments originating from the eroding coasts further North come to rest, we reach the north facing coast of Norfolk. The inshore lifeboat house at Hunstanton has a long history, having been reclaimed by the Institution when it reopened the station in 1979 following earlier closure in 1931.

Wells Next The Sea has one of the best examples of a lifeboat station at the mercy of wind, waves and tide. The boathouse was substantially rebuilt in 1989/90 to house a Mersey, and recently timber revetment and groyne works were necessary when erosion of the sandy headland on which the boathouse stands threatened to cut the station off.

Greenheart from Guyana remains one of the best materials for piling in coastal works, as its high density and resistance to marine borers give it a long life in the sea - although it has the opposite effect on tools used to work it! Greenheart was used at Wells, but no rain forests were depleted as the old timber slipway at Eastbourne had just been dismantled, and the piles proved to be in such excellent condition that they could be re-used to give many more years of service at Wells.

Sheringham has also seen major works, with a new slipway built in 1992 and major modernisation of the boathouse in 1994. Again the RNLI has to maintain groynes to protect the slipway but, in contrast to the sand at Wells, it is coarse shingle and cobbles that are on the move at Sheringham.

As this issue goes to press a large jack-up barge is about to sail from Lowestoft to Cromer, to start work on what will be the largest contract ever undertaken by the RNLI - rebuilding the famous slipway lifeboat station at the end of Cromer Pier.

The previous boathouse was demolished in December 1996 after giving over 70 years of service in some of the most severe sea conditions in the country. The new station will be considerably larger to provide the supporting facilities which the old station lacked and to house the new fast slipway lifeboat now under development.

Building the new slipway and boathouse will be a major project, and access will be almost entirely from the sea as the Victorian pier can support only pedestrian traffic. Planning and design has taken two years and construction - subject to weather conditions - is expected to take 15 to 18 months.

The old boathouse was a listed building and it was with some sadness that it had to be demolished. Various ideas were put forward to preserve the building but the costs were prohibitive and the demolition contractor eventually cut the building in two and loaded it onto a barge. It may yet have a new lease of life, possibly as a museum adjacent to the harbour in Southwold.

The station's Tyne class lifeboat Ruby and Arthur Reed II has been moth-balled and will return once the project is complete. In the meantime cover is being maintained by a carriage launched Mersey on the slipway outside the lifeboat museum to the East of the pier.

The Norfolk and Suffolk coasts are a coastal engineer's nightmare. The full range of timber groynes, revetments, concrete seawalls and more exotic structures line the foreshore. Since Victorian times solid masonry bastions and promenades have held the line at Sheringham, Cromer and other coastal towns while in between the soft and unstable glacial mixture of sand, silt and clay has been eaten away despite man's best attempts at playing King Canute.

Eroded At Happisburgh (pronounced 'Hazeburra') the station's D class launches from a slipway cutting through the continuous line of coast defences which protect the low cliffs, on which caravans and houses are poised perilously close the ever-receding crest. Plans are in hand to extend the boathouse and to give the station improved facilities for the crew and it is hoped that these will be completed later this year or early in 1998.

What gets eroded from one part of the coast must of course get deposited somewhere else, and at Great Yarmouth and Gorleston siltladen waters from both river and sea can deposit up to a metre of sand in the lifeboat's berth on a single tide and periodic dredging is required. In 1992 over £220,000 was spent reconstructing the berth to provide boarding facilities ready for the arrival of a new Trent and in the same year the old boathouse was also extensively renovated to modernise the supporting facilities for the crews, house the Atlantic 21 and provide a new souvenir sales outlet.

Davit At Southwold both erosion and deposition are active. Just north of the town the coastline has been receding by some 6m a year for at least the last 100 years, and complete villages have disappeared beneath the waves. The new lifeboat house, located safely within the harbour, was completed in December 1993 and is finished in black ship lap timber. The station's Atlantic 21 is one of a number of that class launched by davit - in this case over the old quay edge. The RNLI has standardised on a marine Schat davit with a safe working load of 2 tonnes at a reach of 6m.

The design of the Southwold station required a sensitive approach as it is in a Conservation Area, and a particular feature of the building is the excellent 270° view from the first floor crew/operations room over the harbour entrance and the coastline to the north and south. The lifeboat must cross the estuary bar, formed from sand moving steadily south, and the seagull eye's photo vividly illustrates the effect of the north pier of the estuary training works. The pier acts like a groyne and there is dramatic step in the beach line between north and south with the beach at Walberswick lying well to the west of the main Southwold sea front.

Rounding Thorpeness our journey takes us to Aldeburgh famous for its annual music festival and, to some, infamous for the new lifeboat house opened in March 1994. Many things about the Aldeburgh project were special and it is perhaps appropriate that the design of the boathouse should also have been notable - local Woodbridge architects Mullins Dowse and Partners designed both Aldeburgh and Southwold. Lifeboats had been stationed at Aldeburgh since 1852 and the station's Pother was the last 8-knot double-ended lifeboat in service with the Institution. The lifeboat was a feature of the sea front, being launched by slipway from a raised plinth on which she was kept in the open.

At high water there was no problem but at low water the boat often had to be moved on skids across the shingle after failing to reach the sea even though the slipway had been raised to try to counter the effects of the accreting shingle beach.

The nature of the beach at Aldeburgh was both an asset and a problem. Like many stretches of the Suffolk coast land has been lost in recent times, and the famous 15th century Moot Hall which now lies adjacent to the sea front road used to be several streets Lifeboat Stations referred to in the text Building up to the Millennium Continued away from the sea.

Old photographs examined during the design stages showed the sea reaching the seawall in the first half of this century, but the construction of a groyne system led to a steady build up the beach and to the development of a broad shingle berm stretching 30m to 50m from the wall.

It was this berm which provided the site for the new boathouse, but the susceptibility of the beach to future erosion had to be borne in mind. The foundations are surrounded by sheet piling which will preserve the stability of the building should the beach be lost in the future. The prudence of this precaution was demonstrated when in January 1993, just before construction started, a storm tide moved thousands of tonnes of shingle and exposed the groyne system to an extent not seen since the 1950s.

Dramatic The erosion did not reach the site of the boathouse but did produce a dramatic 3m drop some 20m in front of the position of the main doors. As predicted the beach reformed over the following months and, provided that the groyne system is maintained, it is unlikely that a catastrophic loss of the beach will occur.

The unique design of the boathouse which features external stainless steel A-- frames from which the main boathouse and its smaller cousin, the tractor house, are hung has been the subject of critical comment - and caused one Sunday newspaper to make some less than complementary comments accompanied by some less than accurate facts.

Any movement from traditional design will always risk adverse criticism, but the design was chosen in close liaison with both the town council and the planning authority and the finished product has met with a mostly favourable public response.

Crossing the county border to Harwich brings us to a station which has yet to be upgraded to provide the full modern facilities which the RNLI is striving to provide at all stations - a situation which it is hoped will be put right in the not too distant future.

At Clacton plans are being prepared for the modifications needed to house the new 32 knot Atlantic 75. The boathouse is part way along the privately owned pleasure pier and the boat launches via a slipway. After recovery the lifeboat must be turned by lifting and rotating inside the boathouse, and the slightly greater length of the A75 requires some judicious internal adjustments.

The flat and relatively sheltered surround- ings of the new West Mersea inshore lifeboat house - completed in 1992 - seems a world away from the exposed coasts to the north. Yet the silt of the Essex marshes present another set of problems, both to building boathouse and to launching lifeboats.

The West Mersea Atlantic 21 is launched from a conventional trolley, but at low water the rig must be hauled along a lengthy 'hard' across mud flats to the navigable channel. The timberclad boathouse is built on a piled concrete platform with a slipway leading down to the tidal mud flats with launch and recovery assisted by a winch located in the boathouse.

Floating The current leg of our voyage ends in a yacht marina at Burnham on Crouch, where one of the most recent new facilities was commissioned and yet another Atlantic inshore lifeboat has yet another method of housing and launching.

Burnham is one of three stations at which Atlantic 21s and 75s are housed in floating boathouses moored to pontoons. The first floating boathouse was at Brighton, with a later version at Poole.

Both were successful, but the refined design at Burnham has met with considerable acclaim and may well be adopted by the Danish lifeboat service for some of their larger 10m RIBs.

The boat is kept on a hinged platform which can be raised clear of the water when housed and lowered to launch rapidly when required for service. Although simple in concept the dynamics and buoyancy calculations require some care if the crew are not to get their feet wet when the 1.5 tonne boat is raised out of the water. The disadvantage with floating boathouses is that crew facilities cannot be provided within the same building, and separate shore facilities must be provided as close as possible to the berth. Both the floating boathouse and new shore facilities were completed at Burnham on Crouch in the Autumn of 1996.

After a winter lay-up at Burnham Howard Richings' circumnavigation will continue in future issues of The Lifeboat.