massive speed
powerboats (5/10)

Continuing on Five this week is the series that sees Chris Barrie examine the evolution of machines designed for speed. Tonight, he turns his attention to the dangerous world of powerboats, focusing on early stepped-hull boats, record-breaking threepoint hydroplanes and modern racing catamarans.

Reaching high speeds on water is all about the balance between power and drag –how much power can be crammed into the vessel, and how can resistance be minimised. It is this problem that inspired the design of early racing boats, such as the Jazz. In 1912, the two-seater Jazz competed all over Europe and set the pace for racing powerboats. Its four-cylinder, 4.5-litre Vauxhall racing engine ensured the Jazzhad plenty of horse power, but it was its revolutionary ‘stepped hull’ which enabled such great speeds. Halfway along the bottom of the hull was a large step which allowed the boat to ride on top of the water rather that ploughing through it, meaning there was far less drag. “But to see exactly how it works,” says Chris as he climbs behind the steering wheel, “I’ve got to get her moving!”

Throughout the 1920s and most of the 30s, the water speed record was held by stepped-hull boats, the most famous of which was Gar Wood’s Miss America 10. With four 36-litre, 1600-hp aircraft engines, Wood’s machine was more powerful than a freight locomotive and set a record of 124.8mph in 1932. However, on 4th August 1939, Miss America 10’s record was smashed by a tiny blue boat with a third of its power.

The Bluebird K4was a three-point hydroplane – the first example of a brand new design inspired by Chinese suicide attack boats. On its first run in 1939, the K4, piloted by Englishman Sir Malcolm Campbell, reached 141.74mph. Drag was reduced to a minimum through the addition of two floats at the front of the boat, which, along with the propeller, were the only points in contact with the water. “Three-pointers don’t ride on water, they ride on air,” says Chris. While he is not experienced enough to pilot such a powerful machine, Chris is able to try a smaller vessel at a three-point hydroplane racing school. “In the right hands, this tiny training boat will do 70 miles an hour,” he says. “But what will it do in mine?”

After World War II, a new type of engine became available to the speed freaks –the jet was simpler, lighter and infinitely more powerful than a piston engine. In 1955, Donald Campbell followed in his father’s racing footsteps and launched the jetpowered Bluebird K7. Based on the same principle as its forerunner, the K7boasted a 7,500horse power engine and became the first boat to break the 200mph barrier. In 1964, the boat reached a massive 276.3mph, but Campbell wanted more. During an attempt to go past the 300mph barrier in 1967, the K7hit a small wave, flipped into the air, somersaulted then crashed back onto the water –killing Campbell instantly.

Since that time, over half of the attempts to break the water speed record have resulted in fatal tragedies. The current record of 317mph was set in 1978 by Australian Ken Warby in his three-point hydroplane Spirit of Australia.

As Campbell’s tragic case illustrated, threepointers could reach incredible speeds on glassy lakes but could not cope with choppy waters. For massive speed at sea, something completely different was needed –the racing catamaran. These machines combine the speed technology of the hydroplanes with stability, but they are still capable of hitting 160mph over rough seas. The boats that compete in the Class 1 World Powerboat Championship –the biggest, most expensive water sport of all –employ two Lamborghini 8.5-litre V12 engines, making for a serious speed machine. “This is massive speed on an ever-changing surface achieved through maximum power, minimum drag and maximum brown trousers!” says Chris.