A particularly interesting problem was presented in designing to the International Yacht Racing Union’s basic specification for the proposed Two-man Keelboat. The length, sail area, draft and keel weight, with the pointed reminder that a trapeze could be used, indicated the opportunity of a boat that, to us in England at any rate, would be something entirely new; a boat in fact which would plane almost as easily as a top performing centreboarder, but at the same time would have the stabilising factor and security of a keel.

Such a boat was likely to prove the answer to those used to racing dinghies, who find that when they turn their thoughts to keel boats there is nothing which gives a sufficiently satisfying performance, particularly off the wind.

The need for a Two-man Keelboat had been hinted at IYRU Conferences since 1960, but nothing definite had been done before 1963 towards instituting such a new class.

The specific requirements were finally announced by the IYRU in 1963. A design competition was held in Holland, but ten years previously I had entered a boat for the Two-man Centreboarder Trials, from which the Flying Dutchman class was ultimately chosen, and experience indicated it might be best to delay producing and publishing a design until as late as possible to avoid the inevitable tendency towards pooling ideas. It was, after all, my Osprey which introduced the modern technique of trapezing to the Flying Dutchman and 5-0-5 prior to the 1954 Trials, though this was a revival of a less highly developed technique from the 1930s.

In Britain we are fortunate to have three active classes of high performance racing dinghies, in which design is free within the limitations of a rule framework. These classes, the National 14 ft., Merlin Rocket, National 12 footers and International 14 footers, are officially termed "restricted classes," but they are better called "development classes." Many years of continuous development in these classes have produced extremely advanced boats, which both in hull shape and gear bear very little resemblance to their forebears of twenty years ago. Much of my designing experience has been in these classes, which provide an endless source of interest.

One of the most valuable things learned from the long experience of designing for the restricted classes is the effect of each characteristic in the shape of the hull or the design of sail plan and its relation to the lateral plane. In fact there exists the benefit of almost constant tank testing of the most reliable kind, as new hulls and sail plans are evolved, and then sailed competitively. The design of a racing sail boat is inevitably a compromise seeking to achieve a wide range of performance characteristics. Sometimes that compromise is more successful than at others, but at least an experienced designer should know what sort of dish he will produce from the ingredients thrown in the cooking pot. Designers lacking the competitive performance data on fairly closely related designs, such as is found in the restricted classes, are almost inevitably at a disadvantage when it comes to producing a completely new type of boat aiming to achieve a very positive kind of performance. The Tempest was designed against this background.

Obviously, all the contestants in the Trials would use the sail area limit set by the IYRU and it seemed clear also that almost everyone would design to the maximum waterline length that could be contrived, always bearing in mind the official stipulation that "the ends of the boat must appear balanced." It seemed probable also that everyone would choose the minimum permitted keel weight, and this was the case, but there was wide variation in hull weights and general conception, the British boats being lighter than the others and obviously paying more regard to planing performance. Tempest was not the lightest, but was designed for a long racing life in reinforced plastic construction. With the keel and trapezing crew helping the keep the hull upright, it seemed to me that the optimum angle at which the boat should sail would be about 15 degrees, when both keel and trapeze would really be working. Tempests's hull is, therefore, designed to sail efficiently at this angle.

A 22 ft. planing keelboat with 240 square feet of sail could obviously be quite a hair-raising machine in fresh winds when sailed in confined spaces by two people unless the handling characteristics were good. Great attention was paid, therefore, to the manners of this boat to ensure that she had no shrewish vices or wild habits. One of the characteristics of the Tempest which is always remarked upon is her extreme controllability.

It was highly desirable that the new boat should be self-righting after a knockdown in extreme conditions, and entirely self-draining. A fair amount of spray was likely to blow into the cockpit in a boat sailing as fast as this in heavy weather, and to keep the sailing weight as low as possible the cockpit was made to self-drain at all angles of heel and at all speeds. This proved also extremely useful when the boat is left on moorings, as all rain water drains out.

I started designing Tempest in December 1964. W. Richardson and Co. Ltd. of Darlington began building her in February and everything went very smoothly. The boat was delivered in March, without any fittings and unrigged. Fittings were made by Ian Proctor Metal Masts Ltd. and I did most of the fitting out myself, screwing the bits and pieces on personally. My firm also, of course, made the spars and rigging.

She was ready for launching in April and we immediately got down to the job of tuning her. I was very fortunate that John Oakeley who, of course, sails Flying Dutchmen and ocean racers, and Cliff Norbury, who mainly sails National 12s, leapt at the chance of being helmsman and crew. The had both owned many boats of my design and we have done a great deal of sailing together, so it was great fun as well as being a good working team. We were limited to sailing at weekends, but concentrated hard on tuning up whenever possible and Tempest was taken out whatever the weather. Most of the time it blew hard and it soon sorted out any weaknesses. Having such a new type of boat we found that a few of the first ideas of gear needed changing; sometimes we had to toughen up and sometimes to pare down.

Although Ian Proctor Metal Masts Ltd. had some thirty-three different mast sections available, there was not one which was ideally suited to this boat and I designed a new section. The extrusion could not be produced until after we had started to sail her, but as soon as it arrived a new mast was made to give us a bendy rig, which proved highly efficient. The sail plan had been designed with a high foretriangle leaving just enough topmast to produce the right bending characteristics farther down the mast. A bending boom controlled by centre mainsheet traveller was used.

All the equipment was evolved from experience in the Flying Dutchman and other centreboarder classes. We had a very high degree of control over every aspect of the sail plan including, of course, underdeck jib furling devices, internal mainsail clew outhaul, cunningham hole controls, and so on. We also spent a great deal of time getting the sails as we thought they should be.

Division of work between helmsman and crew in a boat like this, which may often be sailed in top competition and make heavy demands on both, is important. Many of the controls normally left to the crew are taken over by the helmsman, who has at his fingertips the spinnaker halyard, spinnaker boom vang and jib furling gear. The spinnaker sheets can be handled by either helmsman or crew, the controlling point being at the bridge deck. The crew can, therefore, concentrate on setting the spinnaker pole and attaching its vang and lift while the helmsman makes other necessary adjustments.

One problem with such a prototype is finding a trial horse against which to tune. We had nothing more suitable on our water than a good fleet of Flying Dutchmen, which was perhaps fortunate as we had to set our sights high and work hard. We had some rapid surprises; the first was that under nearly all conditions Tempest had a comparable performance with the best of the Flying Dutchmen. I expected this to windward, but never hoped for it off the wind in planing conditions, yet we found that Tempest would tear along just about as fast in a plane. We also found that Tempest was faster in light airs. As was anticipated she showed up a little less favourably under the conditions in which the lighter Flying Dutchman would just plane and Tempest, with her 500-lb. keel, just would not.

This planing ability was well beyond my expectations. Certainly the design was intended to produce a boat which would plane fairly readily, but the main objective was that Tempest should best the other boats in the Trails, and I felt certain that some of those would almost ignore planing ability and would aim at speed to windward and light weather performance, both of which are characteristics which conflict with the design of fast planing boats. In any case, it was obvious that a keelboat, carrying 500 lb. of ballast, could not expect to plane as often as a centreboarder and, therefore, to sacrifice windward ability and light weather performance by putting too much emphasis on planing performance would have been a dangerous chance to take. The hull shape was, therefore, a compromise type and certain features which make for out and out planing were not used. For this reason mainly, the transition between the normal displacement sailing of the Tempest into planing is more gradual than for high performance centreboarder types. She does not accelerate and lift in the same way, nor is she intended to.

John and Cliff, being very perceptive sailors, soon evolved a technique for getting the best out of Tempest. This, together with the fact that they never failed to take her out even in the worst weather, produce supreme confidence in the boat and in themselves. They felt that Tempest was invincible, and no doubt this helps.

We tried to think of everything, but I made one stupid mistake in using an untested rudder of a slightly modified shape for the IYRU Trials and it broke in the third race, forcing her to retire when leading. Otherwise our feeling that Tempest was invincible would have been fully justified, for it was the only one of the nine races she did not win. We returned to the original rudder for the rest of the Trials.

During the Trials, Tempest had won under every condition from very light airs to a really strong blow. She had also sailed with 40 kilos (88 lb.) of sand ballast in the cockpit to prove that her performance was not solely due to lightness, and that if subsequent building in plastics made her a little heavier, she would not be inferior to the other trialists.

At the end of the Trials, which were conducted very efficiently, it was announced that no further Trials would be required and that the Selection Committee would recommend to the IYRU Permanent Committee Meetings in November the adoption of the Tempest class as the new International Two-man Keelboat. Some members of the Selection Committee, including the Chairman Jan Loeff, were in favor of granting immediate International status, so that the impetus derived from the Trials would be maintained in establishing the new class. However, the main body of opinion in the IYRU was against this.

Naturally, there is much pleasure to be gained from producing a design which ultimately is successful, but in the case of the Tempest it went much further than this. Throughout the whole campaign there was wonderful co-operation from the builder, sailmakers and everyone else connected with the preparation of the boat. Also, we all hoped that perhaps the Tempest would introduce all over the world a really new and intriguing facet of sailing—the high performance planing keelboat.

Draft rules and measurement plans were submitted by me at the Trials to the Selection Committee, as I had thought that this would be a requirement from every competitor, for only with such rules could the development and future of the classes be assessed. However, I think that Tempest was the only boat to go to the Trials with comprehensive rules. I believe that in future all entries at similar Trials should submit draft rules.

At the end of the Trials Beecher Moore, who was one of the Selection Committee, was asked to work with me to develop the rules further before final submission to the IYRU. Beecher and I, though to some extent business rivals in as much as he is a director of Jack Holt Limited, have been friends for a great many years, and I have crewed for him in Merlin Rocket and Hornet Championships and he has crewed for me in National 12 Championships. He has, of course, been closely associated with the development of Jack Holt’s very successful classes. Working on the Tempest rules was stimulating, and we quickly had the rules ready for presentation to the IYRU Conference. One of the principles was that all molds for plastic boats should come from one source and be derived from a master "plug" or pattern.

Although the original stipulation by the IYRU had been that the class should be for construction in one material only, and it was generally assumed that this would be plastic, representatives from both Holland and Sweden had asked at the Trials that timber construction should also be permitted. The rules that we prepared, therefore, allowed for both forms of construction and to some extent influenced the way in which the rules were drawn up, and the final form of the plastic boat.

Meantime, my prototype Tempest had gone off on demonstrations and boats had been built for Sweden and the U.S.A. Enthusiastic reports began to be received. More than sixty builders applied for licences. The plans and specifications for timber construction and the plans for plastic construction were submitted to Lloyds very soon after the Trials and its opinion eagerly awaited. Meanwhile investigations on suitable production of the plastic boat were made. I hope it will be thought natural that, as Richardsons had supported the project so well prior to the Trials, I wished them to maintain an interest in the production of the boat, provided of course that this did not conflict with the future welfare of the class. Richardsons themselves had no experience in plastic building but were keen to find a subcontractor for the mouldings and assemble and finish the boats themselves, ultimately aiming to produce their own mouldings as experience was gained.

Time was ticking away and I thought it essential to have a plastic boat available at the IYRU November Meetings. Lloyds’ comments had not come through, and after several attempts to get its report it was declared that, if a plastic boat was to be produced by November, it was essential to go ahead without further delay. It was fortunate that we did, as the report eventually came through on 1st October, exactly a month before the IYRU Meetings at which the boat had to be shown. Had we waited for the report it would have been impossible to have produced a boat in time.

Having finished to our satisfaction the Class Measurement Rules, Beecher shook me to the core one day by saying, "Now you must produce the Class Constitution and we will form a Caretaker Committee." The Constitution was drafted and I invited various people to serve on the Committee. Beecher was elected Chairman and under his leadership this Committee has been indefatigable and quite first class, and Dinah White has done a tremendous amount of work as Class Secretary. We held a meeting before the IYRU Conferences and made a few amendments to the class rules, which were circulated to IYRU Delegated in October.

We had hoped that the plastic prototype would be ready for sailing before the IYRU Conference, but in fact she was only finished in time for us to rig her outside the Royal Thames Yacht Club, where the meetings were held, at 2 o’clock at night after the first day of the Conference. The Wraysbury Sailing Club had kindly given us facilities for the wooden prototype to be sailed there if any IYRU Delegates wished to try her.

Various IYRU Sub-committees worked very hard to go through the Tempest rules and constitution during the Conference, and it was a most interesting and exciting time. At the end of it the Class was given official International status.

Immediately, Richardsons were under pressure from many directions to produce official molds to the ratified rules and to send boats to Boat Shows at New York, California, Zurich, Hamburg, Genoa, Paris, Amsterdam, Toronto, and, of course, London. The boat for California had to be shipped within about three weeks. The molds were rushed through and the boats were produced and shipped in time.

The result of this attempt to satisfy the demand to have the Tempest at the major boat shows was very nearly disastrous. The molds did not have time to cure properly and the stiffeners and framework in which they were supported caused distortions. The hulls were shoddy and of a low standard of finish. Deep was the gloom.

There was only one course to take—to start again and build new patterns, pre-production molds, "plugs" and production molds. It was necessary to go right back to the beginning, as the original pattern for the hull had been damaged beyond repair during the making of the first plastic deck mould.

I went to Paris, New York and Amsterdam, as well as, of course, London, and there faced the embarrassment of hearing the criticism of many disappointed potential Tempest owners.

Meantime, the IYRU itself met complications. Arrangements were being made for the IYRU to license boat builders to produce Tempests, but it was found that the IYRU did not exist as a legal body. Now it was necessary to form holding companies to administer licences properly. This all took time.

Richardsons had by now formed a new company specialising in plastics and were employing plastics experts. They were making all the molds themselves, and great care was taken. As the rules of the class stipulated that all building would normally be in the hands of a limited number of selected builders in each country, and that normally there would only be one where the territory could be adequately served by that number, and because these builders would be approved by Lloyds and known to be amongst the best, it was essential that the molds should be of a very high standard indeed. Also, it was intended that all molds had to come from the same "plug" and as boats would be produced from these molds for perhaps the next twenty years or more, only the best was good enough.

Experts came from the U.S.A. and many others offered advice from several parts of the world. Each one had different ideas on how the molds should be constructed, but the molds were ready by March and immediately boats were produced from them.

During all these tribulations, when it sometimes seemed to me that the Tempest Class would never get going as it had promised so well to do, there was a cheering event which revived us. We entered a Tempest in Yachting’s important One-of-a-Kind Races in Florida, U.S.A. at the request of the organisers. Richardsons had sent over one of the early plastic boats, which we knew to be overweight and not up to the quality for which we aimed. We had sails made by Jack Holt Limited and Musto and Hyde, and used these on the plastic prototype on the Hamble to assess them. John Oakeley agreed to go out and take the helm and Ernie Dean, an excellent American Flying Dutchman crew, took on the job as trapeze man.

It was not an easy operation. The Star class made an all out effort against the Tempest and chose Dick Stearns, former World Champion and 1964 Olympic Silver Medalist, as helmsman. The Tempest, apart from being overweight, was taken straight from her shipping crate and had to be sailed immediately, without any real opportunity for tuning. Certainly at least one important tuning modification should have been carried out—the moving inboard of her jib fairleads—but this could not be done to this plastic boat in the time available.

The races were in predominantly very light to light airs. The Tempest won three of the five races and the Star won two in very light going indeed. The conclusion was that in wind speeds of 3 knots and under the Star was faster than the Tempest, but at wind speeds above this Tempest became increasingly superior, and the indication was that at moderate speeds she would really have trounced the Star. She received very favourable reports from the yachting magazines.

Lloyds had required certain modifications to be made to the original construction; mainly these concerned additional stiffeners. Lloyds had also made some helpful recommendations on the laminate specifications to make it suitable for building throughout the world.

As soon as the boats were again in production, another snag arose. I had fixed the minimum weight rule at what I thought was reasonable for the plastic boat as originally specified. Now, producing to the amended specification, Richardsons found they could not get the weight down to the minimum, and boats were coming out between 50 and 70 lb. overweight. Keen racing owners were refusing to take them at this weight. Only by disregarding the rules or the specification could Richardsons build boats which they could sell.

It was suggested that the minimum weight should be raised, but I dug my toes in to resist this and the Class Committee backed me up. Instead, the specification was re-amended and Lloyds’ approval given for construction with fewer stiffeners (as originally designed) and a lighter deck laminate.

Lloyds had, some weeks earlier, made various tests on a Tempest, the results of which they found impressive. A boat was suspended with the bottom of the keel 7 ft. 6 in. from the water and she was dropped from that height. No signs whatever of damage were found. She was then supported under each end and 300 lb. weight applied amidships. The hull deflected only 7/32 in. and, ten minutes after removal of the weight, had completely regained its original shape, though still supported at the ends only.

It was now May. At last everything was set to go. Boats had been proved very strong, yet were down to the target weight. Molds were being shipped to licensed builders at the rate of one every fortnight. Production was up to three or four boats a week in England.

A keel hoisting device was then in production and improved trailers and launching trollies were also produced. The keel hoisting gear works on the screw jack principle and can be positioned and the keel released and raised within four minutes, with little effort. This undoubtedly is an important feature for many parts of the world.

In spite of annoying delays it is now, as I write this, only eighteen months since the IYRU Trials took place and yet we now have an International Class and have successfully held European Championships this year and are organising World Championships in 1967. Tempests are being built in the U.S.A., Canada, France, Italy, Holland, and licenses are being negotiated for Australia, West Germany, Austria, Sweden, Argentina, South Africa, and New Zealand. Probably no International Class has previously made such rapid progress since its debut, or been formed on firmer foundations. I hope that we can look forward to twenty or more years in which the Tempest will give sport and pleasure to people all over the world.