What is Jetsprinting?
Jetsprinting is a sport which originated here in New Zealand back in 1981 where the racers competed in rivers with islands created for the day. Now the tracks are mostly purpose built permanent tracks with launch ramps and safety fences. Jetsprinting could be likened to rallying, only on water, where a driver and navigator manoeuvre a high powered jetsprint boat at incredibly high speeds around a track consisting of a maze of channels and islands in a particular sequence. The track is roughly the size of a rugby field. There is only one boat in the track at a time, they are racing the clock.
The sequence is called a rotation which the drivers and navigators are given prior to race day to learn. The crews must follow the numbers in the correct sequence to achieve a timed run. If they go the wrong way then they have the opportunity to return to where they went wrong and finish the run correctly. If this is not done and the rotation has not been completed correctly then they receive a DNF (Did Not Finish) and no time is given for the run due to a navigational error. If they do not record a time in the quaifying rounds they do not get to continue through to the eliminations. Each boat has a transponder mounted on their roll cage to record their times, if they have forgotten to put their transponder on then it is an automatic DNF and they have no time recorded for that run. The rotation for the day will generally consist of around 25-30 numbers taking around 60 seconds to complete but by the end of the day it will have been reduced to approximately 45 seconds by the superboats.
Jetsprinting uses the elimination format where the racers have 4-5 high speed runs at the course to qualify. Once qualifying is completed their best time is selected from all of the qualifying rounds to find the top 9 who will continue racing that day. From here they are eliminated and previous times are no longer relevant. The top 9 will cut to a top 6, and finally to the top 3 where the 1st, 2nd and 3rd place getters are found, it is only these three who receive trophies. Points are allocated to each competitor according to their placing in the round, these points are added after the completion of the series to find the overall winner, the series consists of 6 rounds creating The Altherm New Zealand Jetsprint Championship.
There are 3 classes:
This class run 412 cubic inch V8 engines with around 500 horsepower. Their engine blocks are made of cast iron and they run on avgas, the hulls are the same as in the other classes as well as the rules and regulations on roll cages and other safety aspects. They have less engine development than the other classes, keeping the engines less stressed helps to keep the costs down. This is seen as the development class and a good place to start racing.
This class also run 412 cubic inch V8 engines and run on avgas but they have bigger carburetors, bigger cam shafts and bigger jet units than the Group B class so they often get more than 600 horsepower from their 6700cc engines. This class is often the most competitive class and a win is generally hard earned.
This is the open class where the only rule is that the boat runs on methanol. These are the big boys toys where you will find boats from 850 - 1500+ horsepower run on big blocks, small blocks, superchargers, turbo chargers, twin turbo's and even a quad rotor turbo (developed in Wanganui, NZ).
These boats can empty a 35,000 litre swimming pool in around 60 seconds, they are one of the fastest machines on earth reaching speeds of up to 130kph in under 2 seconds and are capable of turning in their own length at full speed. Most of the superboats use up to 25 litres of methanol in less than 60 seconds. The boats in all 3 classes weigh around 700 kg and have no brakes. If the engine cuts out they also have no steering!
All competitors wear double skinned fireproof overalls with fireproof balaclava's, gloves and boots. They have helmets and neck braces (some wear a Han's device which straps to their helmets to further protect their necks). They are strapped in with 5 point harnesses with quick release buckles for if they end up upside down in the water. They also wear an arm restraint on the outside arm; this is to prevent them from putting their arm outside the boat if the boat is rolling (said to be an automatic reaction to save yourself and the cause of broken arms when it occurs!). A number of the helmets now have intercoms so the navigator can tell the driver which direction to take, drivers and navigators who don't have these use hand directions although some drivers regardless still prefer to use hand directions for visual confirmation.