Keith lli:ih hn, the ItNIJ's Senior Naval Arrhitn t. looks :it lifeboat development over the past 175 v. rs, Modern lifeboats are highly sophisticated craft with unique features which enable them to survive when lesser craft would be in great difficulty.

Yet despite the huge differences between today's high-tech lifeboats and those in use when the RNLI was founded 175 years ago many of the basic principles had been established even before Sir William Hillary made his historic Appeal.

Indeed many of the basic ideas can be traced back to man's earliest attempts to build livesaving craft, today's success resulting from the advances in technology of the late 20th century.

Lionel Lukin's 'Unimergible Boat' of 1785 introduced the concept of sealed buoyancy chambers, cork tendering and an iron ballast keel and predated the RNLI by 40 years. Other principles which stood the test of time were the reduction of the internal volume able to hold water (by having large internal air tanks) and returning the water to the sea through large drains. Ironically when patented the design was intended to make a safer boat for taking ladies for trips on the Thames! Shortly afterwards, in 1789, William Wouldhave pioneered the self-righting principle which was essentially the same as that used today - ensuring that the centre of gravity is kept low in the boat while providing buoyancy high up to make the boat unstable when inverted.

Elements from these two designers provided the basis for Henry Greathead's Original, usually considered to be the first true lifeboat, which entered service on the Tyne in 1790. Various types of lifeboat were in use around the country before 1824, some making use of Lukin's ideas and other simple rowing boats used by local associations.

The founding of the RNLI in 1824 saw some standardisation, but lifeboats in the main continued to be small self-righting rowing boats Unfortunately the selfrighters had to be narrow to make them work and were consequently rather 'tippy', earning them the name 'self capsizers'.

In East Anglia in particular the selfrighters were unpopular and the 'Norfolk and Suffolk' type evolved to suit the local conditions. These large non-self-righters were heavy and stable, similar to the local working boats, and needed a large crew. To row one for any distance required a great deal of effort, so sailing performance was significantly better than for other types.

They used Lukin's principles of large internal buoyancy tanks and were self draining. They were however very wet in a seaway and few were built.

In 1887 G. L. Watson was appointed as the RNLI's consulting naval architect and the RNLI entered a new era. Watson held strong beliefs that lifeboats should be as stable as possible, and that stability should not be sacrificed to provide self-righting ability. Although his influence was to be felt for the next 60 years self-righting boats continued to be built, and in 1899 237 of the Institutions lifeboats were still self-righters.

Mechanical propulsion and screw propellers arrived early in the new century and by 1910 G. L. Watson and Co had designed the first of many motorised lifeboats with their propellers recessed in protective tunnels.

By now lifeboats were becoming larger, with open rowing boats being superseded by w the semi N enclosed motor boat and self-righting ability was no longer thought necessary.

A reversal of policy followed when R. A. Oakley became the RNLI's naval architect in 1947. Prompted by disasters in the late 1940s and early 1950s Oakley set about designing a lifeboat with maximum stability, but with self-righting ability - the first selfrighter to be designed for almost 100 years. His 37ft and 48ft classes, first introduced in 1958, led the way to seaworthy, self-righting lifeboats. To do this the inherently self-righting form developed by Wouldhave had to be abandoned. Oakley avoided the narrow beam and consequent lack of initial stability by devising a righting system that made use of the transfer of water ballast.

Although Oakley's water transfer system was effective and automatic it was somewhat complex and allowed some water to remain inside the vessel - which could be detrimental to the structure of a wooden boat.

Now that it was no longer necessary to have a narrow boat in order to self-right Oakley's designs held sway until the advent of the new generation of 'fast' lifeboats in the 1960s.

A demonstration of an American 44ft lifeboat in 1963 resulted in its introduction, with a few modifications, as the RNLI's Waveney class. This was the Institution's first 'fast' lifeboat, and marked a return to the inherently selfrighting principles of Wouldhave almost 200 years before.

By now technology and materials had advanced sufficiently to allow the superstructure to be made watertight enough to constitute the high-up buoyancy required to self-right, although the Waveney was still relatively narrow.

The Waveney was followed by the Arun (1971), Thames (1973) and Tyne (1982). Each boat brought its own 'first': steel hulls for the Waveney and Thames, a glass reinforced plastic (GRP) hull for the Arun and a fast tunnel hull shape for the Tyne.

All these new designs were inherently self-righting as a result of their watertight, buoyant superstructures, a feature of all recent RNLI all-weather lifeboats The Mersey class, a fast carriagelaunched lifeboat, arrived in 1988. She also had a tunnel hull, but the real innovation lay in her construction. Following the first few aluminium boats a modern material called fibre reinforced composite (FRO was adopted and each of the FRC internal sections was fitted out before being bonded into the hull. The Mersey was the first class of modular construction lifeboats.

The RNLI's latest designs, the Trent and the Severn classes also adopted the same method of construction. Both can achieve 25 knots and have advanced FRC hulls. The shape too is new, being a 'soft' chine form to promote planing while retaining the traditional RNLI propeller tunnel.

A similar concept is now being developed into the next generation of fast slipway boat, eventually to replace the Tynes.

The new Fast Slipway Boat (FSB2) forms part of the lifeboat service's plans for the next millennium, plans which were largely the result of an overall review under the heading of 'Lifeboats 2000'.

This programme took a long hard look at what kinds of lifeboat and equipment would be needed in the foreseeable future, and is likely to lead to some new types of lifeboat.

So, although today's Severns and Trents would be unrecognisable to the pioneers of lifeboat design the early innovators at least have the satisfaction of knowing that the principles they established still hold good.

If Henry Greathead had access to turbocharged diesels, FRC hulls and polycarbonate windows the Original might have looked a little different…Lionel Lukin s 'Unimergible Boat' Norfolk and Suffolk type/.