This means that the battery is discharged down to 10.5 volts over a 20 hour period while the total actual amp-hours that it supplies are measured. Sometimes ratings at the 6 hour rate and 100 hour rate are also given for comparison and for different applications.
Pool meets are usually no more than 4 hours, but beach meets last about 7 hours. It depends how many events are in the meet. And then if it is a really big meet (like a tournament kind of) it can last days. Hope that helps.
What is the world record time to swim a mile?   There is no World Record for a mile in swimming, the closest event is the 1,500m. What is world record for swimming a mile? 14 minutes 34.56 seconds for long course lap swimming and 14 minutes 26.62 seconds for short course.