Sailing Handicap Calculator (Portsmouth Yardstick)
Calculate corrected time for handicap sailing races using the Portsmouth Yardstick (PY) system.
Compare two boats to find the race winner on corrected time.
What is the Portsmouth Yardstick system?
The Portsmouth Yardstick (PY) is a handicap system used in dinghy and small keelboat racing to allow boats of different designs to race fairly against each other. Each class of boat is assigned a PY number, a rating of its expected performance relative to a reference class.
A lower PY number means a faster boat. The scale is anchored to a nominal reference of 1000: a boat rated exactly 1000 sails the scratch time. Real classes are rated against that baseline, so the Laser, renamed the ILCA 7 by the International Laser Class Association, comes in around 1100, meaning it takes a little longer than the reference over the same course.
The corrected time formula
Corrected Time = (Elapsed Time × 1,000) ÷ PY Number
All competitors’ corrected times are compared, and the boat with the lowest corrected time wins the race, regardless of who crossed the finish line first.
Example calculation
Boat A: Laser (PY 1100) finishes in 45 minutes. Corrected time = (45 × 1000) ÷ 1100 = 40.91 minutes, which is 40:55.
Boat B: Topper (PY 1365) finishes in 52 minutes. Corrected time = (52 × 1000) ÷ 1365 = 38.10 minutes, which is 38:06.
Boat B wins on corrected time by 2:49, despite finishing seven minutes behind Boat A on the water.
Run it the other way to see how tight that is. For the Laser to beat the Topper’s corrected time it would have had to cross the line by 41:54 instead of 45:00, a little over three minutes quicker. On a 45-minute race that is the difference between a good start and an average one, and it is the number the result panel gives you when you enter both boats.
Common Portsmouth Yardstick numbers, from the UK’s Royal Yachting Association (RYA)
| Class | PY Number |
|---|---|
| Laser Standard | 1100 |
| Laser Radial | 1147 |
| RS200 | 1046 |
| Topper | 1365 |
| Optimist | 1645 |
| Mirror | 1390 |
| Wayfarer | 1102 |
| Enterprise | 1122 |
Current PY numbers are published by the RYA and updated annually based on race results.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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