The Flexible Furler can be used with a new or existing sail, but the sail must have #6 luff tape on the leading edge rather than hanks. It is always best to discuss the design of a new sail or the conversion of an old sail with a sailmaker as there are several other options that you might like to incorporate in your furling sail. These include:
1. The size of the sail you will use for furling. A 150% genoa is probably the most popular, but a 135% can also make a lot ofsense. If you are satisfied with your boat's performance with a smaller sail, you may not want to go larger. Small sails look better when reefed down to storm sail size, and it's much easier to tack using a small sail. You have to pull harder and pull more line in with larger sails.
2. The length of the hoist. While most existing sails will fit the furler, the drum and the halyard top fitting do take up room along the luff. If the sail you are converting was close to full hoist, you may have to shorten the luff length to use an old sail with the Flexible Furler.
3. The addition of ultraviolet protection. While this is usually advised, it may not be appropriate if the sail being converted is old and won't last more than a couple of seasons.
4. The fullness of the sail. The Flexible Furler is designed to reef as well as furl your sail. Like all furlers, the Flexible Furler reefs best if the sail is cut relatively flat. Older sails that may have stretched out with time and use can be flattened quite easily during the conversion process.
5. Shape enhancing pads. If you anticipate sailing reefed frequently, you can improve the shape of the reefed sail by having a foam pad sewn on the luff. This pad is about 1/4" thick and is very narrow at the top and bottom and wider in the middle. As you reef, the diameter of the reef is larger in the middle than at the ends, thereby removing much of the draft as the sail is reefed on a constant radius luff extrusion.
6. Lead adjustment. A converted sail will sit somewhat higher on the forestay which may require moving your jib lead aft slightly. If there is no adjustment available, the sail can be recut to bring the lead forward. Remember, when reefing, the jib lead must be brought forward.
Remember, it is best to discuss these items with your sailmaker, taking into account the condition of your sail, the type boat you sail, the area and wind conditions in which you sail and the way you anticipate using your boat. Only the addition of luff tape and item 2 must be done. The others are improvements and not always necessary.