Les Staudacher and the Jet Boats
More Power to You
Les Staudacher is the only man in the U.S. who has designed, built and driven a jet-powered boat. He had considerable driving hours with Tempo Alcoa before she blew up this June .while being tested with remote radio control. His experience with that craft resulted in the following observations Les recently made to me:
"The greatest problem in designing a jet boat is getting around the wave-making resistance at low speed. This factor, that has presented little problem in most hydroplane designs, gives you fits with a jet job both while accelerating through the 'displacement boat' speed range and decelerating through it. Whatever configuration you use must be so designed that it throws no spray upward. Flying water is sucked into the jet intake with disastrous results.
"So far our attempts to produce a hull form that minimizes wave-making resistance, to allow us to get on a plane, have been aerodynamically poor at high speeds. Their bottom air lift area tends to 'stall' at high speeds, resulting in an abrupt shift in behavior.
"This business of getting on a plane is especially tough with a jet because-despite the high thrust rating of the engine-it seems that, at low boat speed, a good outboard could tow the jet rig backwards while the jet engine was wide open.
"All that counts at high speed is the aerodynamic factor. Our tests have shown that aerodynamic problems are simple compared with the wave-making bit. From what we know, the 4,000 to 5,000 pounds of thrust developed by far-from current jet engines should easily give us a boat speed of 500 m.p.h."
For those of the fraternity who have visualized jets powering everything from unlimited hydros to the smallest classes intended for youngsters, Staudacher has some disturbing views. Based on his experience lie can not foresee jets being used in any kind of competition. Here are his reasons.
"I found .it was almost impossible to steer the boat until she had attained a good planing speed. After the headache of overcoming wave-making resistance the boat would 'break loose' and behave well around 50 m.p.h. Then, about 80, she would bog down to the point that the sponsons tended to bury and the tunnel bottom was riding on the water. To get through this phase, the jet engine had to be opened up wide. After a bit of this full power, the boat would break loose again and accelerate from 80 to 200 m.p.h. in six seconds. Better you should have her aimed right when she enters this stage! All of this adds up to the fact that there isn't enough room on the average race course to get a fleet of jets going and under control.
"Tempo Alcoa threw a low but very wide rooster tail. There was so much water thrown out over such a wide area that passing her on a race course would be a virtual impossibility.
"You mentioned that you thought a jet would be the best hope of the U.S. in regaining the Harmsworth Trophy. Please remember that a jet engine consumes 1,000 gallons of fuel each hour. A boat carrying enough fuel to get through a 45-mile Harmsworth race would be so overloaded that she would not be able to develop any real high speed.
"When Tempo Alcoa was running at speeds above 200, it required real mileage to stop her. After cutting off the power on calm water she would travel a good half-mile before coming to a stop. If there was a chop, it took three to four times that distance to bring her to a halt. This would be too dangerous in competition. It was just this that made me run up on that peninsula out at Pyramid Lake last fall. I could see the thing in front of me but couldn't steer away from it and couldn't stop."
(Reprinted from "More Power to You" by Mel Crook, Yachting, November 1960, pp.87-88)
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© Leslie Field, 2001