Genoa (sail)

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A genoa (pronounced like the city, or as jenny) is a type of large jib-sail used on bermuda rigged craft, commonly the single-masted sloop and twin-masted boats such as yawl and ketch. Its large surface area increases the speed of the craft in moderate winds; in high wind conditions a smaller jib is usually substituted, and in light winds a spinnaker may be used.

[edit] Definition

A jib, left, compared to a roughly 150% genoa, right. The foretriangle is outlined in red.

The term genoa is often used somewhat interchangeably with jib, but technically there is a clear delineation. A jib is only as large as the foretriangle, which is the triangular area formed by the mast, deck or bowsprit, and forestay. A genoa is larger, with the leech going past the mast and overlapping the mainsail. To maximize sail area the foot of the sail is generally parallel and very close to the deck when close hauled. Genoas are categorized by the percentage of overlap. This is calculated by looking at the distance along a perpendicular line from the luff of the genoa to the clew, called the LP (for "luff perpendicular"). A 150% genoa would have an LP 50% larger than the foretriangle length. Sail racing classes often specify a limit to genoa size. On International Offshore Rule boats, different classes of genoa have 150%, 130%, and 98% overlap, and so on. Under Performance Handicap Racing Fleet rules most boats are allowed 155% genoas without a penalty.

[edit] Handling issues

Maximizing the sail area causes more difficult handling. It is harder to tack a genoa than a jib, since the overlapping area can become tangled with the shrouds and/or mast unless carefully tended during the tack. Genoas are very popular in some racing classes, since they count only the foretriangle area when calculating foresail size; a genoa allows a significant increase in actual sail area within the calculated sail area. In boats where sail restrictions are not applicable, genoas of 200% overlap can be found, although those over 150% are not often seen, since the additional area is shadowed by the mainsail when close hauled and generates diminishing returns in terms of power per actual sail area.

[edit] The gennaker

The gennaker is a fairly new type of sail, and as the name suggests it is a hybrid between a genoa and an asymmetrical spinnaker. A brand name of North Sails, the gennaker is a cruising sail based on the Code 0 spinnakers used on racing boats. Gennakers and similar code 0 variants offered by other makers are even larger than genoas (200% overlaps are not uncommon) and they have a much greater camber for generating larger amounts of lift when reaching. Flat cut gennakers can be effective for angles as low as 60 - 70 degrees. Spinnakers perform much better when running because the main sail blocks the wind of gennaker above 135 -150 degrees.

[edit] External links

• North Sails G-series cruising gennakers