What is the Portsmouth Yardstick system?
The Portsmouth Yardstick system is a formula that facilitates fair racing between dinghies of different speeds. Using the Portsmouth Yardstick formula the race finish times can be adjusted to remove the advantage of sailing a faster boat.
It’s predominantly used by dinghies and small keelboats, but the formula could be applied to any type of boat.
What’s the history?
In 1947, Stanley Milledge of Langstone Sailing Club came up with a new system allowing for different classes to race each other. It was called the Portsmouth Yardstick. Milledge’s system became THE system used for handicap racing in the UK. It was adopted by the RYA and has remained integral to handicap racing ever since.
But it’s not just Brits that use it. Sailors ‘across the pond’ in the US also use the system, and in 2020 they submitted race results to the RYA for the first time.
How does the Portsmouth Yardstick system work?
Each class of boat is given a number which represents how fast the average boat in that class goes around a racecourse. For instance, how far the average ILCA should be ahead of the average GP14. This number is arrived at by analysing historical race results.
This number allows mixed fleet racing as the race finish times can be adjusted for ‘corrected time’ using the Portsmouth Yardstick formula.
The formula is a simple one: Elapsed time divided by PN x 1000 = Corrected time
PN= Portsmouth Number
This “corrected time” adjusts the order of finish times, so the results are ordered by skill rather than by class of boat. This allows boats of different classes to race against each other fairly (at least in theory). We’ll discuss the pros and cons later in the article.
Who creates the Portsmouth Number List?
The RYA issues the list each year. They have a committee of volunteers who analyse the race results submitted to the RYA. As well as looking at race results, they also consider other factors such as performance trends and comparing lakes to the sea.
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