Use a reliable existing sail specification when one is available. Otherwise, the finished dimensions are established from the boat, rig, intended use and confirmed furling system.
If you have an existing sail or specification
Enter the known finished dimensions:
| Configurator field | Meaning |
|---|---|
| Luff | Finished leading-edge length, including the sail’s cable arrangement as specified |
| Leech | Finished trailing-edge length |
| Foot | Finished lower-edge length |
| Mid Girth MGM | Width between the luff and leech midpoints |
Send the existing measurement report where possible. If the sail sets well and the new sail must replace it directly, its finished dimensions are normally the clearest starting point.
If the sail must be designed from the boat
Start with the tack point and halyard exit, then account for the complete furling assembly. The available hoist is reduced by the drum, top swivel, shackles, adapters and cable terminations.
This is why Cable & Furler comes before this page. A nominal masthead-to-tack distance is not enough to approve a finished luff.
Photographs may be requested of the bowsprit, tack fitting, masthead, halyard exit and sheet leads. TPS and ISP are available in the Pro view as rig references.
Mid girth defines the role
Mid Girth MGM describes how flat the sail is relative to its foot. The system displays MGM / SF as a calculated ratio and Pricing Area as the commercial area result.
A Code Zero is flatter than a gennaker so it can work at tighter angles and furl evenly. If a rating certificate requires the sail to meet a particular classification, state the rule before design.
Additional rating measurements such as HLP, HHB, HUW, HTW and HQW are available in the Pro view. They are not ordinary requirements for every cruising order.
Sailmaker Review
The finished dimensions are checked together with the furler model, cable construction, cloth and intended use. A mismatch between an old sail specification and the current boat arrangement is resolved during Sailmaker Review, not silently changed.