Like any sport, when you're at the edge of what is possible then things go wrong very easily!

Dr Hugh Hunt

The thrill-seeking television action man sought out senior lecturer Dr Hugh Hunt to help with the technical side of an episode in the series in which Guy undertakes four speed-based challenges, in an attempt to explore the boundaries of physics and learn about the science of speed.

Hugh explained: “Guy Martin is completely insane! He decided to break various speed records, one of which involved riding a motorbike on water (hydroplaning).  Having previously done the Dambusters bouncing bomb television programme on Channel 4 I was asked to help out on various aspects to do with the bike 'bouncing' across the water.

“My approach was to start with small experiments in the hope of learning something before making mistakes at a bigger scale. 

“There were various questions:

1.  Is there an optimum speed to ride at?

2.  How important is entry angle?

3.  Will the bike be stable?

4.  Will Guy be able to steer?

5.  Will he be able to maintain speed?

“All of these can be 'answered' by doing simple experiments.  We found that the sand tyre gave enough 'thrust' to keep the bike going, but above a certain speed it would scoop out so much water that it was just pushing against air.  40mph seemed to be about the right speed.

“Entry angle was very important, as shallow as possible, just like skimming stones.  An area that concerned me was that the suspension would recoil as it entered the water.  This was a factor in the final run, but Guy managed to establish steady conditions and hydroplane really well. 

Stability is vital and steering would be impossible on water which is why a ski was fitted, shaped like a boat so that it goes in a straight line.  This is allowed in the 'rules' for riding on water.

“Maintaining speed, once all the conditions are right, was down to Guy - could he manage to balance all the delicately-poised factors for 100 metres which was the distance set to qualify for a new world record?  It's like any sport, when you're at the edge of what is possible then things go wrong very easily! 

“The team did a great job, and maybe if the weather had been better Guy could have done a few more runs - but that's the way it goes, and we were delighted that he made 63 metres which is two thirds the length of a football ground!”

The episode of Speed featuring Hugh can be seen for a limited time on Channel 4’s catchup facility: http://www.channel4.com/programmes/speed-with-guy-martin/4od#3627103