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A genoa sail is a type of large
jib
A jib is a triangular sail that sets ahead of the foremast of a sailing vessel. Its tack is fixed to the bowsprit, to the bows, or to the deck between the bowsprit and the foremost mast. Jibs and spinnakers are the two main types of headsails ...
or
staysail
A staysail ("stays'l") is a fore-and-aft rigged sail whose Sail components#Edges, luff can be affixed to a stays (nautical), stay running forward (and most often but not always downwards) from a mast (sailing), mast to the deck (ship), deck, the b ...
that extends past the mast and so overlaps the main sail when viewed from the side, sometimes eliminating it.
It was originally called an "overlapping jib" and later a genoa jib. It is used on single-masted
sloop
A sloop is a sailboat with a single mast typically having only one headsail in front of the mast and one mainsail aft of (behind) the mast. Such an arrangement is called a fore-and-aft rig, and can be rigged as a Bermuda rig with triangular sa ...
s and twin-masted boats such as
yawl
A yawl is a type of boat. The term has several meanings. It can apply to the rig (or sailplan), to the hull type or to the use which the vessel is put.
As a rig, a yawl is a two masted, fore and aft rigged sailing vessel with the mizzen mast p ...
s and
ketch
A ketch is a two- masted sailboat whose mainmast is taller than the mizzen mast (or aft-mast), and whose mizzen mast is stepped forward of the rudder post. The mizzen mast stepped forward of the rudder post is what distinguishes the ketch fr ...
es. Its larger surface area increases the speed of the craft in light to moderate winds; in high wind, a smaller jib is usually substituted, and downwind a
spinnaker
A spinnaker is a sail designed specifically for sailing off the wind on courses between a reach (wind at 90° to the course) to downwind (course in the same direction as the wind). Spinnakers are constructed of lightweight fabric, usually n ...
may be used.
Definition
![Jib vs genoa](https://upload.wikimedia.org/wikipedia/commons/6/6e/Jib_vs_genoa.svg)
The term ''jib'' is the generic term for any of an assortment of ''headsails''. The term ''genoa'' (or genny) refers to a type of jib that is larger than the 100% foretriangle, which is the triangular area formed by the point at which the stay intersects the
mast, and
deck or
bowsprit
The bowsprit of a sailing vessel is a spar extending forward from the vessel's prow. The bowsprit is typically held down by a bobstay that counteracts the forces from the forestays. The word ''bowsprit'' is thought to originate from the Middle L ...
, and the line where the
mast intersects
deck at the rail. Colloquially the term is sometimes used interchangeably with ''jib''. A working jib is no larger than the 100% foretriangle. A genoa is larger, with the
leech
Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodie ...
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
A point of sail is a sailing craft's direction of travel under sail in relation to the true wind direction over the surface.
The principal points of sail roughly correspond to 45° segments of a circle, starting with 0° directly into the wind. ...
.
Genoas are categorized by a percentage representing their area relative to the 100% foretriangle. Sail racing classes often specify a limit to genoa size. Genoas are classified by their size; a modern number 1 genoa would typically be approximately 155%, but historically number 1 genoas have been as large as 180%. Number 2 genoas are generally in the range of 125–140%. Working jibs are also defined by the same measure, typically 100% or less of the foretriangle. Under
Performance Handicap Racing Fleet
Performance Handicap Racing Fleet (PHRF) is a handicapping system used for yacht racing in North America. It allows dissimilar classes of sailboats to be raced against each other. The aim is to cancel out the inherent advantages and disadvantages ...
rules, most boats are allowed 155% genoas without a penalty.
Handling issues
Maximizing the sail area can cause more difficult handling. It may be harder to
tack
TACK is a group of archaea acronym for Thaumarchaeota (now Nitrososphaerota), Aigarchaeota, Crenarchaeota (now Thermoproteota), and Korarchaeota, the first groups discovered. They are found in different environments ranging from acidophilic the ...
a genoa than a jib, since the overlapping area can become fouled among 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 do not apply, genoas of 180% overlap can be found, although those over 150% are rare because the additional area is shadowed by the mainsail when close hauled and generates diminishing returns in terms of power per actual sail area.
The gennaker
The
gennaker
A gennaker is a sail that was developed around 1990. Used when sailing downwind, it is a cross between a genoa and a spinnaker. It is not symmetric like a true spinnaker but is asymmetric like a genoa, but the gennaker is not attached to the for ...
has been around for several decades now, and as the name suggests, it is a hybrid between a genoa and a symmetrical
spinnaker
A spinnaker is a sail designed specifically for sailing off the wind on courses between a reach (wind at 90° to the course) to downwind (course in the same direction as the wind). Spinnakers are constructed of lightweight fabric, usually n ...
. A
brand name
A brand is a name, term, design, symbol or any other feature that distinguishes one seller's good or service from those of other sellers. Brands are used in business, marketing, and advertising for recognition and, importantly, to create an ...
of
North Sails
North Sails is an international sailmaker and sailing wear company with operations in 29 countries. The company designs, engineers and manufactures sails for racing and cruising sailboats from 8 feet (2.5m) to more-than 200 feet (60m) in length. Li ...
, the gennaker started as 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
Camber may refer to a variety of curvatures and angles:
* Camber angle, the angle made by the wheels of a vehicle
* Camber beam, an upward curvature of a joist to compensate for load deflection due in buildings
* Camber thrust in bike technology
* ...
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.
History
The famous Swedish sailor and shipowner
Sven Salén
Sven Gustaf Salén (7 November 1890 – 29 October 1969) was a Swedish sailor who competed in the 1936 and 1952 Summer Olympics. In 1936, together with his wife Dagmar Salén, he won a bronze medal in the mixed 6 m class as the helmsman of the b ...
(1890–1969) first used the genoa on his 6 m R-yacht ''May-Be'' by the 1926 in Coppa del Tirreno in
Genoa
Genoa ( ; it, Genova ; lij, Zêna ). is the capital of the Italian region of Liguria and the List of cities in Italy, sixth-largest city in Italy. In 2015, 594,733 people lived within the city's administrative limits. As of the 2011 Italian ce ...
, hence the name. He successfully used it during the Scandinavian Gold Cup's races of 1927 in Oyster Bay (US). Sven Salén also pioneered the parachute spinnacre.
A similar type of jib was in use for centuries by the fishermen in the Netherlands with their Botter type ships. The fishermen relied on the combination of a large jib while fishing so the mainsail could remain unused. After fishing the fisherman's jib helped to get the fish to markets fast.
A correct explanation of the interaction between jib and mainsail was published by aerodynamicist and yachtsman Arvel Gentry in 1981,
A Review of Modern Sail Theory
Proceedings of the Eleventh AIAA Symposium on the Aero/Hydronautics of Sailing September 12, 1981 and "is much more complicated than the old theories imply". This states that the widely believed explanation of the slot effect is "completely wrong" and shows that this is not due to the venturi effect
The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section (or choke) of a pipe. The Venturi effect is named after its discoverer, the 18th century Italian physicist, Giovanni Battista V ...
(or "valve effect" to use Curry's term) accelerating the air in the slot. Instead it is shown that the air in the slot is slowed and its pressure increased reducing the tendency of the mainsail to stall, that the mainsail reduces the air pressure on the lee side of the jib accelerating that airflow, and that the mainsail increases the angle at which the air meets the luff of the jib, allowing the boat to point higher. Gentry points out that proper understanding of sail interaction allows better sail trimming.
References
{{DEFAULTSORT:Genoa (Sail)
Sailing rigs and rigging