The Portsmouth Yardstick is a handicap scheme which allows different types of boat to compete against each other (slower boats being given a higher handicap).
The higher the handicap the more time you have over other boats.
Examples:
| Class | PY | Class | PY |
| Phantom (RYA) | 1012 | Albacore | 1055 |
| Phantom (HSC – sail nos 1100- yr2012) | 1025 | Pico | 1265 |
| Phantom (HSC – sail nos 999-1100) | 1035 | Enterprise | 1117 |
| Phantom (HSC – sail nos pre 999) | 1047 | Solo | 1148 |
| Laser | 1087 | Topper | 1313 |
| Laser (with radial sail) | 1117 | Mirror | 1385 |
| National 12 (RYA) | 1077 | Supernova | 1070 |
| National 12 (HSC – sail nos 3415 on) | 1077 | Pico (singlehanded) | 1260 |
| National 12 (HSC – sail nos 3272-3414) | 1104 | Gull | 1363 |
| National 12 (HSC – sail nos 3141-3271) | 1115 | Gull (S/H) | 1345 |
| National 12 (HSC – sail nos 2512-3140) | 1130 | ||
| National 12 (HSC – sail nos 1600-2511) | 1130 |
