There seem to be a lot of ties in the pool at the Rio Olympics, and not the kind you buy at Brooks Brothers.
Last Friday, swimmers Michael Phelps, Chad Le Clos, and László Cseh all scored identical times in the 100m butterfly to win the silver. (Phelps no doubt needed the silver to break up the sheer monotony of all that gold.) On the previous night, Simone Manuel of the USA and Canadian Penny Oleksiak tied for the gold in the 100m freestyle.
Computer-based timing can capture events down to the millionth of a second. However, FINA, the global governing body for swimming, won’t even drill down to thousandths-of-seconds. Why might that be? It seems they used to do just that. Back in 1972 (Munich), Gunnar Larsson of Sweden beat the USA’s Tim McKee in the 400m individual medley by 0.002 seconds. That led FINA to scale down timing by a significant digit. Why would they do this?
Basically, not all pools are created equal. There will be some discrepancy in their size.
Deadspin explains that “In a 50m Olympic pool, at the current men’s world record 50m pace, a thousandth-of-a-second constitutes 2.39 millimeters of travel.”
If you’re feeling lost right now, bear with me because here’s the key: FINA pool regulations allow for a tolerance of 3 centimeters in each lane. This means, based on the pool, a swimmer’s time could vary pretty significantly. So you can “time a swimmer down to a thousandth-of-a-second, but you can’t guarantee the winner didn’t have a thousandth-of-a-second-shorter course to swim.”