A pursuit race turns the usual handicap race on its head. Instead of the fleet starting together and sorting out corrected times once everyone is ashore, the slower boats are sent off first and the faster ones have to chase them down. Whoever is in front when time runs out takes the win.
Why clubs run a pursuit race
For most clubs the weekly racing is ordinary handicap racing, and the pursuit is the one that breaks up the season. It is usually a one-off, often an annual fixture with a trophy on it, put on to give the members a different sort of day and throw the whole fleet together for once. Because the result is settled out on the water, there is no waiting around afterwards, which suits an open meeting or a social race day where you want the winner known the moment the gun goes.
How a pursuit race works
Every class is given its own start time worked out from its Portsmouth Number. The slowest boats go first and the quickest go off last, and the gaps are set so that if each boat sailed exactly to its handicap they would all meet up at the same place at the same time. The race runs to a time limit rather than a set number of laps. When the time is up the committee boat fires a gun, and the boat that has got furthest round the course has won. There is no finish line to cross and nothing to add up later. Where the boats are lying when the gun goes is the result.
Working out the start times
A class's delay behind the first start is the race length multiplied by one minus its PN divided by the slowest class's PN:
Start delay = Race length × (1 − Portsmouth Number ÷ Slowest PN)
The slowest class in the fleet comes out at zero and starts on the gun. Every faster class waits longer in proportion to how much quicker it is.
Worked example
A 90 minute pursuit starts at 09:00:00. The slowest class entered is a Topper (PN 1363), racing against a Laser (ILCA 7, PN 1104) and an RS400 (PN 942). These are RYA national Portsmouth Numbers.
| Class | PN | Start delay | Start time |
|---|---|---|---|
| Topper | 1363 | 5400 × (1 − 1363 ÷ 1363) = 0 s | 09:00:00 |
| Laser (ILCA 7) | 1104 | 5400 × (1 − 1104 ÷ 1363) = 1026 s | 09:17:06 |
| RS400 | 942 | 5400 × (1 − 942 ÷ 1363) = 1668 s | 09:27:48 |
The divisions do not come out to whole seconds, so each delay is rounded to the nearest second, which is what the calculator does.
The pursuit race calculator does this for every class in your handicap list and gives you the full start sequence.
How it differs from a normal handicap race
A pursuit and a handicap race are sailed round the same course in the same boats. What changes is when each boat starts and how you get a result. In a handicap race they all start together and you correct the elapsed times by PN afterwards, so nobody knows where they finished until the numbers are run. In a pursuit the handicap is baked into the staggered start, so the boat in front when the time runs out has won and that is the end of it. The fleet stays bunched up and you can see who is doing well, which is what makes it fun to sail and to watch. The work for the race officer is setting all those start times beforehand, and that is what the calculator is for.