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.
How many laps is 400 meters? A regulation Olympic-size pool is 50 meters long, so it takes four laps of swimming from one end of the pool to the other to complete 400 meters. The 400-meter freestyle swim for men and women is part of the summer Olympic games.