Welcome, from sunny Australia!
Water Speed Record Boat

If you thought the Land Speed Record car - the MiG-29 - was odd, then you haven't seen anything yet!
The current Water SpeedRecord boats are up to over 300mph on the surface of the water, but the Russians may have a gadget that would allow a far greater speed to be achieved, albeit underwater.

In the late 1980's, some clever chap-ski's in Russia discovered that they could reduce the friction of a torpedo through the water by quite a bit by fitting it with a gas generator to make lots of bubbles around the nose of the torpedo. This reduced the 'wetted area', and so for the same power the torpedo went faster. The problem was that with all the bubbles in the water, the propellors were now having trouble with cavitation.
Skip a couple of years ..
The Russian Shkval torpedo has a conventional warhead, but is powered by a rocket engine that also doubles as a gas generator. By using these apparently odd methods to power the torpedo, it can reach the frightening speed of over 230kts (425kph) underwater for quite some distance!!  The current version can only go in a straight line, but the next generation is going to be wire guided and so turned as needed to chase targets. As I write this, there are no counter-measures to such a torpedo.

But to the point - using such technology it should be possible to build a human guided torpedo that could shatter the WSR. I'm not sure if the record rules state that they boat has to run with part of it above the surface, but I bet they don't.
I think that the hardest part would be to find some nutcase to steer the thing! :)
 

On to the -
- Geothermal Power Plant
- Laptop computer electronic circuit simulator
- Anti-aircraft missile system
- Horizontally opposed diesel aircraft engine
- Different electric car
- Listening spy device
- Super cooler device
- Radar Jammer
- Land speed record car contender