One number for how a design performs.
Race Edge will not tell you who wins on Sunday. It tells you which design wins more often over a season — scored from 1 to 99 against the boats it actually races.
What it measures
Every boat that goes racing declares what it is: its size, its weight, the sail it carries. From that, organisers work out the allowance it gets — the rating it races under, and the time it owes or is owed at the finish.
That allowance is a promise about how fast the boat ought to be. Race Edge asks a simple question about it: over a whole fleet of boats built to the same design, does that promise get kept?
Some designs sail better than the allowance they are given. Others give away time they never get back. That gap — measured across every boat of the design we hold, at every wind strength and every angle — is what the score describes. A design at 80 is beating what its own numbers ask of it, and doing so consistently. One at 20 is fighting them.
How to read it
The score is a position among the boats a design races against, not an absolute speed. A 90 in one class and a 90 in another are not saying the two boats are equally quick — each is saying the same thing about its own company.
Light air, medium, heavy
A design is rarely the same boat in six knots and in twenty. Long, narrow hulls that reward patience in the light go backwards when it blows; flat, powerful ones come alive. So the score is given three times, once for each band of breeze, and the difference between them is often more useful than the overall figure.
If you race where the wind is reliably light, the light-air figure is your figure. The overall score is an average of conditions you may never see.
Does it actually predict anything?
Fair question, and one we put to the test rather than argue about. We took every pair of boats that finished the same race — one against one, on corrected time — and asked how often the design with the higher score came out ahead. The archive held well over a hundred thousand such meetings when we last ran it, and it grows every season.
The higher-scored design finished ahead comfortably more often than not, and the margin widened as the two scores grew further apart: where one design outscored the other by a wide margin, it came out ahead closer to two times in three.
Real, and a long way from certainty. Crew, start and tactics decide a single race, and the same design has won nearly all of its meetings with one crew and almost none of them with another. Over a season the design shows; on a given Sunday, often it does not.
What it is not
It is not a prediction of a race. It is not a measure of how well your boat is sailed, and it will not tell you whether to buy one — two examples of the same design can differ by half a knot on sails, bottom and rig tune alone.
On planing hulls we mark the score not verified. When we ran the check above on those designs, the result went the wrong way: the higher-scored boat finished ahead less often than chance alone would suggest. We would rather say so on the page than quietly hope nobody tests it.
When there is no score at all
Plenty of pages carry no Race Edge. It means one of three things: too few boats of that design have been measured on today's scale for the figure to hold still; its class holds too few designs to rank against; or the boats disagree so widely about what the design is that an average would describe none of them.
Those pages still carry the speeds, the rig and whatever race record exists. A missing score is a statement about our data, not about the boat.
Where to start
Look up a design you know and see whether the number matches what you have seen on the water — that is the only test that will convince you. Then put two designs side by side and see how they have actually finished against each other.
Browse the designsCompare two boats
Think a score is wrong? Tell us at race.edge@tackregatta.com. We have changed our minds before when a sailor knew something the data did not.