MOTOR BOATING.

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MOTOR BOATING.

A ” PUMA ” SPEED BOAT ON TEST.

THE scope for the enthusiast for motor sport on dry land is at present extremely limited in this country. Practically all hill-climbs, which used to be the happy hunting ground of the amateur, have been stopped, and events of a really sporting character at Brooklands are comparatively rare. Every enthusiast will hope that the suggestion put forward by our editor in our August issue for an amateur car T.T. in the Isle of Man will meet with the success which it deserves ; but in the meantime many sportsmen would do well to turn their attention to the sea, if they wish to supplement their opportunities for motor sport.

For this reason we were extremely anxious to test one of the new ” Puma” racing boats, which have been adopted as a class boat for racing by the two clubs organising the sport in England—the Royal Motor Yacht Club and the British Motor Boat Club. The boats are manufactured by Messrs. Saunders of Cowes, who have already won so much fame as the builders of” Ursula.” the fastest Displacement boat, as opposed to hydroplane, ever built, “Maple Leaf IV.” which won the International Trophy in 1912 and 1913, “Maple Leaf V.” which defended it in 1920, and” Newg ” which won the Duke of York’s Trophy in 1926—to mention but a few of their triumphs. Five ” Puma” boats have already been built and sold to private owners, while a sixth is in course of construction ; but as none of the boats have as yet been built for stock the manufacturers were unable to give us a test run. By the courtesy of Mr. H. ScottPaine, however, the owner of Puma I., we were able to have a run on one of these boats, in order to give our impressions for the benefit of readers of Motor Sport. In the first place let us give a brief description of the boat. The engine is the 240 h.p. 6-cyl. Armstrong Sicldeley ” Puma” aero engine, which was used by Sir Alan Cobham in many of his best known flights, and which therefore needs no detailed description. The engine is cooled by fresh water, which in its turn is cooled by water drawn from the sea. From the engine the drive

is taken forward to a gear box by which the final drive back again to the propellor is geared up. Thus when the engine is running at 1,400 r.p.m.—its highest useful crank-shaft speed—the propeller is doing 2,200 r.p.m. By this method considerable tortional stresses are saved on the propeller.

The hull takes the form of a multi-step hydroplane, its characteristic being that it is first built as a plain hull with transomes running from bow to stern, and the four steps are then added. This makes for much greater strength than if the hull is built in steps, and at the same time gives the advantage of a double bottom, so that if one has the misfortune to strike any solid flotsam, it is improbable that at most more than one step will be damaged, and there will be no danger of the boat sinking.

Accommodation is provided for seven or eight persons forward of the engine, while the mechanic’s cockpit is situated in the stern.

Having got on board the ” Puma ” and settled ourselves on the front seat, our mechanic started up the engine, and we toured gently down the Itchen into Southampton Water, while the water and oil were allowed to warm up. Once this process had been completed however, we really began to move ! The acceleration of the boat was really astonishing, the bows lifting steadily out of the water till finally we were hydroplaning beautifully. We watched the rev, counter rising steadily till it finally crept up to just over 1,400 r.p.m., at which engine speed we were informed by Mr. ScottPaine that the boat was doing some 39 knots or about 45 m.p.h. Land motorists may regard this speed as somewhat tame, but in actual fact anyone who has experienced it on the water will agree that it is quite as thrilling as twice the speed on land, in exactly the same way that

90 which is exciting enough as a rule on the road, is exceptionally boring in an aeroplane. In the Puma” boat the rush of water past the sides gave one the impression of travelling like a projectile. Two white mountains of spray rose on either side of the front seat to disappear in our foaming white wake, but scarcely a drop came into the cockpit, in any circumstances. The boat was fitted with a small inclined windscreen which very effectively shot all the air over the passengers’ heads, but if one stood up one obtained the full impression of speed.

There was a fair breeze blowing on the day of our test and the sea was faintly choppy even in Southampton Water. In these conditions the actions of the boat gave an impression very similar to that of a car with shockabsorbers screwed up tight travelling over a pot-holey road ; and when we got into the wash of a steamer after passing close under her stern the action was perhaps more like that of an aeroplane striking a succession of air pockets. Outside in Southampton Water we came upon the ” Aquitania ” going out with the aid of a tug. We proceeded to run rings round her much to the joy and

excitement of her passengers who waved enthusiastically; and in fact the performance of the ” Puma ” made one feel madly inclined to cheer. The comfortable cruising speed of the boat is about 39 m.p.h., which corresponds to an engine speed of 1,200 r.p.m. At this speed she was rock steady, and Mr. Scott Paine showed us that one could leave go of the steering wheel completely and the boat would continue dead on her course. He put the helm hard over, and the boat came round banked at a very steep angle so that it felt like a car on the banking of a track ; and then suddenly rela.esed it, and the boat came back with a flick into an even keel and shot off at a tangent to the circle she had been describing. He then gave us a demonstration of a racing turn round a buoy. On approaching our mark, he decelerated, so that the bows

dropped gently down on to the water, put the helm over and accelerated progressively round the buoy in rather the same manner in which one might take a hair-pin turn on land. The deceleration of the boat when the throttle was shut was of course very striking and reminiscent of a good set of four-wheel brakes.

In all circumstances one received the impression that the boat was eminently sea-worthy and Mr. ScottPaine informed us that he had taken her over to Cowes when the ordinary passenger paddle-steamers had been stopped by the weather. In all we formed the impression that the ” Puma ” boat was a thing to be coveted by every enthusiast for motoring sport ; and we can give no better advice to anyone who can spend 21,350, than to order one of these boats, and to look forward to a season of real sport in 1928.