How does ski race timing work? (part 2)

Part one covered the fine precision required for ski racing timing, and the start gate.  Now that we have a racer on course and the clock is running, let's follow him down the course to the finish.  While the racer is on course, the running time you see on the TV is very, very close to the actual time on course, but it's often not official, because it's based on a computer clock, not the actual timing chronometer.  In some cases, the timing chronometer has an integrated computer processor that runs the race software, so the displayed running time does reflect the official chronometer.  Once the racer passes through the first intermediate timing point and breaks an infrared photocell beam, the timing chronometer stamps the time of that impulse and the computer immediately calculates the time elapsed since he left the start gate and "freezes" this time for the TV display.  The computer software also calculates the difference between the time for the racer on course and that for the leader, usually showing a new leader with a green differential number.

The photocells at the intermediate timing points are set up outside the safety netting, so on a wide "speed" course (downhill or super-G), they might have to "shoot" up to 75 metres.  In between racers, there can be quite a bit of traffic on the course, such as course slippers and course repair workers.  So, the intermediate photocells require an operator, who tells the chief timer when a racer is passing through, and pushes a button to close the circuit and allow the photocell impulse to be registered and attributed to the racer.

At "speed traps", the racer's speed is measured using either a radar "gun" or two sets of photocells set a measured distance apart along a straight section of the course.

The finish uses two pairs of photocells that are vertically stacked.  The snow between the photocells is marked with red dye so that the racers can see exactly where the finish line is.  The finish controller tells the chief timer when a racer crosses the finish and keeps an eye out to warn any non-racers approaching the finish to use a side exit, rather than crossing the finish.

The start and finish are obviously the important timing points, so there are multiple back-up timing systems in place at these locations.  First, there are two or more back-up electric timing systems connected to the start gate and photocells.  Secondly, there is manual timing, which involves hand timers pushing a button when the start gate opens and the finish line is crossed, and writing those times down.  Finally, the very high end races now also use finish line cameras as an additional back-up.  These cameras can scan the finish line at a rate of 1000 line scans per second to build an image record of the finish.

The governing body of ski racing sets strict requirements for timing equipment to be authorized for use in race timing and also requires that chief timer complete timing audit report, which is reviewed by the senior race official at the event.  With all the attention to equipment, procedures and back-up systems, we can ensure accurate and reliable race results.

That's it - all you didn't really need to know about ski race timing. The bottom line is that it really is extremely precise and there are multiple back-ups in case something goes wrong.  Of course the expectation of the timing crew is always that each of the systems will work flawlessly throughout an event!

The photos and text here provide examples and a general description and are not reflective of the systems  in use at the Games at Whistler.