Start times? Perhaps you are refering to handicaped racing numbers or calculations?
You can find handicap info on ussailing.org
That would be portsmouth numbers.
Portsmouth Yardstick Handicapping System â€“ The Portsmouth system is a time-on-time system that uses the Thistle as the standard boat in the United States. While PHRF generally addresses what we term as "offshore boats", Portsmouth addresses up to medium-sized production cruiser-racers as well as multihulls and centerboard classes. Each boat is assigned a series of numbers that are applied based on the average wind conditions of the race. Using the Portsmouth system corrected time (CT) is calculated using: CT = ( ET / HC ) x 100
ET = Elapsed Time
HC = Applicable Portsmouth Handicap number