Natural

Slipstreamers

You don’t often see a fish riding a bike,

so they’re not the obvious creatures to

turn to when you’re looking for tips about

making one go faster, but when it comes

to streamlining fish have got it sussed.

RETTY much every sea creature is

streamlined. Seals or sea lions, even

penguins – clumsy customers on land,

but in the water they are fantastically graceful

and their streamlining is spot on. Being a

slippery shape is all very well, but fish know

a thing or two about slipstreaming as well.

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A school or shoal of fish may swim together

for protection, the idea being that if a bigger

fish comes along and decides that it’s time for

lunch, when it attacks the school can scatter

at high speed, making it more difficult for

the big fish to pick a target. The school then

quickly regroups, but they don’t just close up

in a random bunch. The fittest, strongest fish

swim at the front and the tiddlers follow close

behind, staying safe from predators in the

middle of the school but also making use of

the slipstream effect.

With the larger fish cutting through the water

ahead of them, the smaller ones have the

benefit of the slipstream and don’t have to

work so hard to keep up. That way the school

can move more quickly without having to slow

down to let younger, slower fish stay with the

group. The leaders have first sitting for dinner

when the school swims into a feeding area,

but I suppose that’s a perk of the job. You can

see perfect examples of animals slipstreaming

when you watch horse racing. The Sport of

Kings, they call it – thoroughbred racehorses,

like racing cars or motorbikes, costing a king’s

ransom to buy and maintain. Our own Queen

has been mad about horse racing since she was

a young lass and as an owner she knows a thing

or two about what makes a good runner.

One of her favourite races is the Derby, run on
Epsom Downs to the south west of London.

At the Epsom Derby the horses cover a course

that is just over 1½ miles. There are no jumps

but they do have to run up a bit of a slope, all at

a sprint, so the riders try to grab any advantage

they can. At the end of a race, when the horses

are galloping for the finish line, they look

like they are going flat out but, due to fatigue,

they are actually running more slowly than

when they first hit top speed. That top speed

will probably be about 40 mph, which might

not sound very fast to anyone who’s ridden a

motorbike or driven a car, but imagine trying

to control a bike or a car when it is bucking

around beneath you and you can’t even use

your hands to hold on. Instead you have to half-

crouch, balanced with your feet in metal loops

that are moving around, the only way to keep

yourself on board being to grip the beast with

your knees!

You need proper skill to ride a racehorse, and
a lot of courage. Not many champion jockeys
can say that they’ve never taken a tumble, and
most of them have memories of broken bones

32    Britain’s Fastest Bike