## How do they measure open water swims?

### How do they measure open water swims?

I've always wondered this... how do you accurately measure the distance of an
open water swim?  Measuring distance over land is usually done with a wheel and
odometer, but what method is used to measure distance over water?

john//

### How do they measure open water swims?

At a local triathlon where the swim is point to point, they use
a 100m rope, lay it end to end dropping a buoy every 100m until they
have covered the distance.  I assume they calculate for the sag
factor of the rope.

### How do they measure open water swims?

Quote:
>I've always wondered this... how do you accurately measure the distance of an
>open water swim?

At the Lake Berryessa swim, they use lasers and reflectors (I don't know
the name of the equipment) which measure distance.  Basically one person
sets up a laser at the start line while another gets on a boat with a
reflector.  When they get to the desired distance, they drop the buoy
or anchor.

There's usually some error because of the slack between the anchor and the
buoy or the anchor and the boat but it's reasonably reliable.

Tim

### How do they measure open water swims?

Quote:

>I've always wondered this... how do you accurately measure the distance of an
>open water swim? Measuring distance over land is usually done with a wheel and
>odometer, but what method is used to measure distance over water?

Up here in Canada it is easy - wait until winter, then go out on
the lake when it is frozen and measure it the same way as you
measure over land - no kidding, that is what a race director for
a triathlon here in Calgary has done.

Shane Esau

### How do they measure open water swims?

Quote:
>Up here in Canada it is easy - wait until winter, then go out on
>the lake when it is frozen and measure it the same way as you
>measure over land - no kidding, that is what a race director for
>a triathlon here in Calgary has done.

Just wondering,
how do you account for droughts when the water level goes down, and that
makes the distances shorter?

How about the fact that when the water freezes it expandes, and therefore the
distances on ice are a bit longer, unless the measuring points which are not
on the ice, or in the water.

Sasha