Sailing downwind is more than just looking pretty. Closely examining a used sail can be the difference between a sailing efficiently or like a slug.

There is no reason to feel like you are cutting corners when buying a used sail. By their nature, sails are expensive, and one man’s surplus or under used equipment can become another man’s treasure, but you don‘t want to buy a lemon either. This little test is specifically about buying used spinnakers and asymmetrical sails using .5 oz to 1.5 oz fabric weights.

I drove 50 miles down to Newport Harbor to check out a used .75 oz spinnaker for my boat Baseline. I have a great .5 oz and a decent 1.5 oz., but was feeling that a decent .75 oz would complete the inventory. The sail was rated by the store as a 7+ on a scale of 1 to 10, and ‘very excellent’ according to the vendor. The chute was listed for $795, which is a considerable savings from a new, identical sail priced at $4300.

The salesperson handed me the sail bag, and it felt light, a good initial sign. The store has a outside area where the sails can be laid out and examined and measured. I snapped the head to a fence and drew the sail out of the bag and laid it in the sunlight for a look. At first glance, the sail looked in good shape, and I was about to go ahead and take the tape measure to it to reconfirm the specs.

As I walked the 52-foot length of the luffs I decided the time was ripe for my personal fabric test which I have used for years on my own spinnakers and drifters. I took a 12-inch square section of material and held it firmly against my mouth. I then expelled all the air I could muster, trying to blow air through the sail material. I move along and take another section, then another. If there is any air passing though these test sections, the sail is history. A new, or good sail will not allow any air to pass. Age has little effect on this test other than the sail is most likely "blown out," or loses it shape over time.

The sail looked good and there were no patches or signs of other damage, but in the end, this sail was history. But since the fabric had been stretched beyond its wind range the surface had become porous; the sail could not hold air, negating any imaginable trim to get a good air flow over the surface. By being able to blow air through the sail, the fabric was allowing air to pass from the positive pressure side into the negative side, and thus creating turbulence in the air flow. This kind of turbulence will rob a spinnaker of about 20% of its power producing flow.

I don’t doubt that the sail will fly well and that only a trained eye will see that it has suffered matrix damage, but by using this simple test you can even judge how well a spinnaker will work before you have it all out of the bag. Just reach in and grab a piece, blow, grab another, and another. Then decide what condition it is in. Most spinnakers can be recut for a reasonable cost; so don't pass up a good sail that is just a bit too long here or there. Don’t be fooled by a beautiful form when the chute is flying, or the fancy colors that match you boat. Instead, go for quality and optimum power, and revel in the fact that you’re sailing as efficiently downwind as possible.