Famous Speedboats of the World
In July 1952 the world heard for the first time that the well-known racing motorist Mr. John Cobb, who in his car Thunderbolt had established the world's land speed record, was turning his attention to high speed on the water and was having a boat built. Like Sir Malcolm Campbell, he turned from record speeds over the land to attempt those on the water.
Already, by the time the public announcement was made, about three years of research and experiment had been undertaken with the object of discovering what kind of boat would be necessary if a speed of more than 200 m.p.h. were to be attained. John Cobb's car had been designed by Reid Railton, the brilliant American engineer who had already worked with Sir Malcolm Campbell, and Railton was called in to advise on the design of the proposed record-breaking boat. His vivid, facile imagination conceived a new idea for speed over the water. He visualised, he said, a body not even able to float on its own, but just big enough to contain the engine, the pilot, and the necessary amount of fuel. It was to be as small and light as possible.
Attached to it by arms or outriggers were to be fittings in the nature of water skis, able to provide enough buoyancy and stability to support the body, and on which it would skim over the water. This was the idea from which grew the boat later to be called Crusader.
Though the idea was new it contained the germ of an older one. You may remember that in 1872 the Admiralty Experiment Works had produced a model that consisted simply of three flat floats secured together in the form of a triangle. Then it was intended to apply the design to a large and heavy ship of ocean going type. But in those days there were no engines powerful enough to drive such a vessel.
Now Reid Railton proposed just such an arrangement, but for a small and very light boat that was to be jet propelled. But many problems had to be solved first. The kind of boat visualised was entirely different from the Bluebird, which skimmed upon the bottom of its own hull, not on skis attached to it. How should the skis be arranged? What shape and size should they be? Not only was the speed that it was intended to reach much higher than any yet attained by man on the water, but the craft in which it was done was of a hitherto unknown kind of which nobody had any experience.
Two big problems faced the designers. At the speed contemplated a boat would tend to behave like an aeroplane. The air forces acting on the body of the boat might lift it out of the water. The second problem was to avoid that porpoising action which, we noted, spoiled the performance of Bluebird after she had been fitted with jet propulsion. This was to be the most difficult problem of all.
To solve the difficulties models of one-sixteenth the full size were made. On a bullet shaped body, about two feet in length, various arrangments of skis were tried, and the model was run at high speed in the testing tank of the Admiralty Experiment Works near Portsmouth. After various changes and adjustments, an arrangement was devised which allowed the model to run steadily at high speed without porpoising or losing its stability. The eventual design differed somewhat from the original idea of three simple skis attached to the body of the boat by legs.
The two skis at the stern were built up into floats or sponsons, these providing strength, buoyancy, and a more secure means of attachment to the body. Forward the body of the boat had a flat surface which supported it on the water when at rest or slow speed. All this long, slow experimental work was undertaken by the very experienced Commander Peter Du Cane and his firm, Messrs. Vosper, who were to build the boat once a satisfactory design had been discovered.
The time now came to run a larger model under conditions that reproduced those that would be experienced by the boat herself when skimming at more than 200 m.p.h. So a model one-sixth of full size, or about five feet in length, was constructed, and special rockets were produced by means of which the model might be jet propelled over the water. Commander Du Cane wrote about the first time that this big model was tested:
"In the early morning of January 25, 1951, a few of us were delighted and thrilled to see our model literally leap into life . . . . . . . and run at high speed, controlled directionally by a gyro, for 2,000 feet down the middle of an artificial `lake' 150 feet wide." On that successful run the model reached a speed of 9711 m.p.h., and this represented to scale, a speed of 240 m.p.h. for the full-sized boat.
Many more tests and trials had to be made, and inevitably the model was often smashed up owing to collision as it rushed over the surface of the water at speeds approaching 100 m.p.h. One of the busiest men during those days was the model maker, who often would be given the model in several small pieces and instructed to put it together again-a matter sometimes of weeks of work. Finally, after many small changes and modifications, and very many trials, it was decided that the best possible type of hull had been devised. John Cobb, Reid Railton and other experts came to watch the model being put for the last time through its paces, and it was decided to build a full size boat like it.
Lightness combined with strength was the necessity if the boat was to be driven at more than 200 m.p.h. by the De Havilland Ghost jet engine, which was capable of delivering a thrust of 5,000 pounds. Here again the designers were facing the unknown. At speeds of more than 200 m.p.h. the enormous intensity of pressure that the water would exert on the bottom of the hull or the sponson floats would be more like the concentrated attack of numerous sledge hammers swung by giants than anything else that could be visualised. Everything would depend upon the structure not only being light but also strong enough to withstand such pressures without bending or breaking. For at such high speeds either of these weaknesses would lead to the boat's destruction.
So, for all parts of the hull and sponsons that had to endure these massive pressures, a strong alloy of aluminium was used. Every possible care was taken to ensure the necessary strength, but since nobody had ever moved over water at the speeds that were being aimed at it was not possible to know how great the pressures experienced would be. It was all an adventure into unknown regions. Men had moved far from the days of the large, relatively heavily built Miss Englands travelling at about half the speeds of those now of interest for Crusader.
The unusual boat was eventually ready for her preliminary trials, and it was hoped that these, which were to be conducted at fairly low speeds, might have been made on Portsmouth harbour. But the weather made this impossible, though Commander Du Cane was able to take the boat out for one brief run.
In late August Crusader was taken north to Loch Ness. Meanwhile all the complicated organization of a record-breaking attempt was being set up by the team manager, Captain George Eyston, himself a former holder of the world's land speed record. The work entailed fitting out a workshop, storing fuel, arranging the facilities for launching Crusader and lifting her out of the water, fixing up the wireless communication that was to link the pilot of the boat with his team on shore-these and a hundred other details that breaking a record under modern conditions entails. It is not surprising that each attempt must cost the person making it a handsome fortune.
Not only is there the complex organization but, for the pilot, the constant nervous strain involved in making the many progressive trials while the boat is being gradually worked up to her maximum possible speed. Much patience, too, is required when faced with delays and difficulties caused by weather or the necessity for modification to the boat. The public who read in their newspapers of a new
record being set up, easily overlook the many times that the boat has been put over the same measured mile, or taken out for trial runs while some detail of her behaviour is examined, before she is at last fit to make those final bursts of speed, once up and once down the measured distance, that will enable her to establish a record.
Though Crusader was soon put in the water and the engine given its finishing touches, the water of the loch was not calm enough for a run until the 10th September. Then she was again launched, and she had a couple of trial runs. As so often happens, difficulties began to appear. The sledgehammer attack of the water on the bottom of the hull began to deform its shape and the plating had to be strengthened by internal reinforcements. More serious than this was the fact that it proved very difficult to get Crusader into her high speed running trim. This was not an unexpected problem. A boat, even such as this, runs at low speed much like any other craft, carried by the buoyancy of the water. But at high speed she skims, as you know, on a few square feet of the planing surfaces. To get into this condition the boat must lift herself out of the water. But there is always a tendency for her to stick to the water, to be sucked down to it. This was happening to Crusader. When the throttle was opened she failed to lift herself free from the water and skim. One method of getting over this difficulty adopted by John Cobb was to have a couple of boats run over his course ahead of him and roughen the surface by their wash. This had the effect of breaking the suction which held Crusader down.
Another difficulty had occurred at low speed, but this had been remedied earlier. Before Crusader had increased her speed enough for her nose to rise, the heavy spray that she made came up into the two large open air intakes that fed her hungry jet engine. This trouble was cured by means of spray deflectors placed over the two openings. Eventually everything was ready and the official timekeepers and observers were sent for, whose job it was to establish the speeds of the boat officially.
On the morning of the 19th September it was proposed to make the attempt on the record, and before dawn thousands of spectators began lining the banks of the loch. But the typical Scottish weather intervened to modify the arrangements, and it was considered that the water conditions were not good enough to make runs over the mile at full throttle. But two runs were made and timed by the officials. On the first of these Crusader, though held back from her maximum speed reached exactly the speed of the record that it was her object to beatthe 185 m.p.h. of Slo-Mo-Shun. But on the second run a wind blowing across the course made it difficult for the pilot to hold Crusader straight on her course.
These timed trials had shown that Crusader was probably the fastest boat in the world. In April 1949, three years and five months earlier, she had been a vague dream in the head of Reid Railton. Those years had been necessary to develop and perfect, so far as ingenuity could manage, the tiny strangelooking craft that now sped over the waters of the loch with so much noise, leaving the long smoke trail of her jet engine far astern. Then disaster came.
For observers watching even closely from the shore or in launches near the course, it was difficult to see what happened to Crusader. At one second her pilot had been hurling her at tremendous speed down the measured course; at the next she had seemed to disintegrate or explode; almost before there had been time to realise that she was no longer skimming noisily along the lake, there was silence and a pall of smoke hanging over the spot where she had met her end.
A few careful watchers, however, noticed that a few seconds before the accident all did not seem to be well with the boat. They saw that John Cobb was being bounced up and down in his seat with a kind of violent vibration, and that Crusader herself appeared to be caught in the dreaded porpoising motion which, as we have seen, may so easily be fatal for a boat at high speed. But in spite of observers who watched the accident, we should still today be uncertain about what actually occurred but for the evidence of the cine camera.
There was one focused on her during her last moments, taking sixteen photographs in each second and covering the period of 15½ seconds immediately before and after the accident. A close study of the 248 photographs shows the sequence of events during the fatal seconds. As the boat approaches the camera it is possible to see the rhythmic rising and dipping of the bow, a motion that seems quite gentle if the pictures are shown in slow motion, but which in fact was happening so quickly that it constituted violent porpoising. Immediately before the accident one shot shows the bow up slightly with light showing beneath the hull as far aft as the sponsons. A quarter of a second later the bow is dipped, with spray being thrown by its forward extremity. Then the dive begins. One sixteenth of a second later water is driving up through the cockpit with great force, and this no doubt knocked the pilot into senselessness.
It seems likely that the bottom of the hull, at the point where the pounding had been worst while the boat was porpoising, had collapsed under the massive hammering that it had received from the water, allowing the water to come up through the bottom of the cockpit. Less than half a second later the hull, which dived below the surface, can only be seen in small pieces of flying wreckage amongst the smoke. When Miss England II capsized and sank at a speed of 120 m.p.h. it had been possible to salvage and repair the hull afterwards. But when the smaller, lighter Crusader dived whilst going nearly 100 m.p.h. faster she was inevitably broken to pieces. At speeds of more than 200 m.p.h. on the water there is no room for any accident, and the smallest error or misfortune is likely to cause disaster.
John Cobb was picked up from the water with numerous injuries, but the doctors were of the opinion that none of them were enough to have killed him, and that he actually died from shock.
Having failed to complete both runs Crusader was unable to qualify for the world's record, which must be based on an average of two runs; but the Marine Motoring Association did officially recognize John Cobb's performance as "the fastest speed ever obtained on water", this having been achieved when Crusader, on her first run, reached 206.8g m.p.h.
(Reprinted from Famous Speedboats of the World by D. Phillips-Birt [St. Martins Press, 1959], Ch.8)
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