It’s the time of year when most of us look back on the season past to remember the good times, attempt to forget the bad, and also think about how to improve next year. A big step toward this goal is taking a hard look at the sail inventory and evaluating what’s good, what’s bad, and what’s ugly, yet maybe usable for another season. Te main reason it’s appropriate to do this now rather than during the spring rush is twofold: sailmakers offer significant fall discounts, and your memories of these sails are fresh from just having used them.

But what criteria do you use to separate the inventory into these three broad categories?

First, have a critical look at each sail and evaluate what Will Keyworth at North Sails Chesapeake calls its “functional condition” and then it “performance condition.”

“By functional I mean its physical shape,” says Keyworth. “If it’s been patched heavily, been repaired several times, or has delaminations in the cloth, then it may be beyond repair or re-cutting and should be replaced. Then, even if you use it for a non-serious regatta and it blows up, you have a replacement ready.”

If the sail passes this first test, then it’s on to the test where “performance condition” means something much more subtle: how the sail hold its flying shape relative to what it was designed to do when new.

“Just like people, sails will start to change shape with age,” says Keyworth, “so we want to look at how a sail has been able to hold its designed depth and draft position in its range of windspeed. As the material shrinks or starts to breakdown and stretch, the shapes tend to migrate toward being flat-forward and draf-aft.” This less-than-ideal shape creates more drag than lift.

Critiquing sail shape is now easy using photographs of a main or jib. Sailmakers use sofware that can analyze the shape of the sail, usually along the middle and upper draft stripes, to measure depth and draft position. North Sails’ Dave Scott uses such a tool, called Sail Scan, and an example of a J/109 sail analysis is shown below, which depicts all the relevant dimensions of the sail’s flying shape in the existing conditions of wind speed, angle, and rig tune.