Jetsprint

From Wikipedia, the free encyclopedia

Jetsprint or sprint boat racing^[1] is a form of racing sport in which jetboats with a crew of two race individually against the clock through twisting series of channels in less than a metre of water.^[2]

Tracks are typically designed for spectators, and racing is fast and loud, with boat motors usually powered by V8s developing well over 500 hp.^[3]

History

Jetsprinting as an organised sport originated in New Zealand in 1981, and events were originally held in the same natural braided rivers that had inspired Sir William Hamilton to develop the jetboat, but when the sport was introduced to Australia in the mid-1980s permanent artificial courses were used—and this is now the norm even in New Zealand.

A fiercely contested Tasman championship has now led to a three way world championship (with the introduction of the sport to the United States, under the auspices of the Union Internationale Motonautique^[4]). The host nation rotates between New Zealand, Australia and the U.S.A

Format

The race itself will consist of a predefined course through the channels with 25 to 30 changes of direction. These races generally take just 45–60 seconds. Once qualifying is completed the competitors each run the course with the fastest qualifiers running last. The fastest 16 (typically depending on the number of competitions) proceed to the next round. This is then reduced to the top 8, then the top 4 and then the fastest two.

Boats

A jetsprint hull is typically short - just 4 to 4.1 metres (13 to 13½ feet) long. The hull's vee is usually 23 to 25 degrees with several strakes on each side. A short hull is preferred, as a longer hull takes more distance to turn and usually must be turned at a slower speed. The strakes provide "traction' by stopping the boat sliding sideways across the water when turning at high speed.

A rollcage must be fitted to the boat.

Crew

A crew consists of the driver and a navigator whose responsibility is to guide the driver through the course - typically via simple hand signals, pointing the hand in the direction that the boat must go at the next intersection.

Classes

There are two internationally recognized classes

Class A - Engines in Class A boats are restricted to either 6.7-litre (412 cubic inch) engines with cast iron blocks and heads or 6-litre (365 cubic inch) engines with aluminum heads. Both size engines are only allowed two push-rod operated valves per cylinder. Furthermore the engine must be normally aspirated, using a 4-barrel carburetor. Fuel is 100+ octane aviation fuel. Typically these engines produce up to 650 horsepower

Super boats - Engines in the super boat class have no maximum size but instead have a minimum size restriction. Normally aspirated engines must have a displacement of 6.5 liters (400 cubic inch) or while forced induction (turbocharged or supercharged) engines must be at least 3.8 liters (235 cubic inch) in displacement. These engines typically are fuel injected and run methanol fuel. The small-block engines typically produce 950+ horsepower, while the big blocks can typically produce between 1000 to 1400 horsepower.

Nitro-methane and nitrous oxide are not allowed.

External links

References

This article is issued from Wikipedia. The text is available under the Creative Commons Attribution/Share Alike; additional terms may apply for the media files.