THE Royal National Life-boat Institution has been criticised from time to time for being slow in adopting modern designs and techniques.

Such criticism largely arises from a lack of appreciation of several factors which have militated against the rapid adoption of a progressive policy.

In the first place the safety of life-boat crews is of paramount importance. This means that no new design or equipment can be adopted until it has been exhaustively proven. Consequently it can take four or five years before a new design can go into quantity production.

The same criterion applies to new materials 'Commander Swann is the Chairman of the R.N.L.I.

The article is condensed from Tackling World for January, 1973, and is reproduced with the Editor's permission.

such as g.r.p. which was considered 10 years ago but not proceeded with, because it was felt at that time to be insufficiently tried and there was uncertainty as to the life of the material.

But perhaps the greatest handicap was simply the size of the fleet; about 160 boats with a life of 25 years if afloat, or 30 years if housed, followed by perhaps 10 years on relief duties.

It was not feasible to scrap more than the annual replacement number—of about five boats; the number of building yards is very limited and the cost would have been astronomical.

Two-thirds of the R.N.L.I. fleet of 160 boats are launched either down slipways or from carriages and in a few cases down a beach, and, until comparatively recently, it was the policy of the Institution that life-boats should, as faras possible, be inter-changeable. Accordingly nearly all boats were capable of being launched down a slipway. This meant a standard midship section and hull form with the propellers in tunnels, not only to protect the screws, but also to prevent cavitation.

With such a design it was virtually impossible to get more speed; neither was it felt desirable to do so, as speed was considered at that time to be inconsistent with seaworthiness. So it was that there was very little change in basic life-boat design during the period 1920-1960.

The first major change came in 1958 with the introduction of the 37-foot Oakley selfrighter.

This boat was designed because the five post-war capsizes had shown the need for self-righting boats; with the life-boat staying bottom up once she capsized, the crew had little chance of escape.

Following the success of the first boat some 24 have been built and have given a good account of themselves, largely replacing boats of the 35-foot 6-inch Liverpool class.

Recently the Institution has developed a Mark II version of the 37-foot boat, the object being to enable radar to be installed, to provide a covered steering position for the protection of the crew and also to enable the boat to be selfrighting without the need for the transference of water ballast; the boat is simply unstable in the capsized position by virtue of her profile.

The 37-foot Mark II, built of wood, is the smaller of the two classes of conventional lifeboat now being built by the Institution. The other is the 48-foot 6-inch class, the prototype of which was completed in time to be shown at the 9th International Life-boat Conference at Edinburgh in 1963.

The constructional details of the boat were then revised for building in steel, in the expectation that this would be a cheaper form of construction.

In the event, the overall saving was only about 10%. So much of the cost of a boat is the equipment put into it, that the difference in the cost of hull material is a relatively small part of the whole.

The opportunity was taken to make the boat self-righting without the need for the transference of water ballast—an important point in view of the very high cost of the non-return valves in the earlier boats.

These steel hulled boats are known as the Solent class, of which eight boats have been built, and three more of a Mark II version are under construction.

Following a visit to the Life-boat Societies in Holland and Germany in 1961, it was decided to build two 70-foot boats which could be used either for patrolling or as station life-boats.

They are fine, seaworthy boats, like a small trawler.

These two boats, which went into service in 1965, have carried out many services, that of the second boat, 70-002 stationed at Kirkwall in Orkney, last November, being particularly meritorious. Apart from their draught, the main disadvantage is that such boats are expensive to build and man. However, as two boats cannot beoperated without a relief, a third boat is being built at Bideford for launching in July, 1973.

The first step towards faster boats for the Institution came with the purchase of a 44-foot steel life-boat from the United States Coast Guard in May, 1964. After successful evaluation, the Institution built six boats to this design, giving them an aluminium instead of a steel deck. A further eight of these boats are currently on order.

Experience of these six boats in service has been very satisfactory. It has been shown, for instance, that they can operate in shoal water without undue risk to the propellers. They lie afloat. Shortly after their introduction, the Institution designed a 50-foot boat to similar basic design, also to be built of steel. The tank tests were satisfactory, but no boats were built at that time. However, two of these boats are now being built. This is an exciting project.

As already mentioned, there was some resistance at the beginning of the period to the introduction of faster life-boats but this has gradually lessened, when it was realised that faster boats could be built without sacrificing seakeeping qualities, and also that many life-boat crews were asking for more speed.

Moreover and most important it was necessary to have faster boats to enable the Institution's fleet to be deployed to the best advantage, both operationally and economically.

Consequently a staff requirement was drawn up for a 20-knot boat, fully self-righting with an rll-weather capability, which would lie afloat, length to be about 52 feet and draught 4 feet 9 inches. Arun is the result. She was built of cold moulded ply and launched in May last year; this hull design is capable of speeds up to 28 knots, but with the machinery installed, a top speed of 19.95 knots was achieved. She is a good seaboat. Her chief disadvantage is her high freeboard. The second prototype will be better in this respect, as the deck line is lowered amidships, thus making it easier to haul a man out of the water.

A great deal of thought has been given to g.r.p. construction and the Institution has been fortunate in being able to call on much expert advice. As a result, it has been decided to build a third prototype in cold moulded ply from which a plug may be made for possible eventual construction of the hull in g.r.p.

The second and third boats will have rather more power than Arun so as to achieve 22 or 23 knots which is considered sufficient. The third prototype will have a rounded transom but a similar deck layout to the second boat.

Another project which is at an interesting stage is a design for a steel slipway and afloat lifeboat.

The object is to produce a boat which will have an all-weather capability, but which will be easier and cheaper to build than the Solent class. She will be fully self-righting and possibly a little faster than the Solents.

There have also been considerable developments in the field of inflatable and small craft.

Much experience has been gained since the (continued on page 452).