Gennaker
Encyclopedia
Sail
A sail is any type of surface intended to move a vessel, vehicle or rotor by being placed in a wind—in essence a propulsion wing. Sails are used in sailing.-History of sails:...
that was developed around 1990. Used when sailing
Sailing
Sailing is the propulsion of a vehicle and the control of its movement with large foils called sails. By changing the rigging, rudder, and sometimes the keel or centre board, a sailor manages the force of the wind on the sails in order to move the boat relative to its surrounding medium and...
downwind, it is a cross between a genoa
Genoa (sail)
The genoa or jenny was originally referred to as the 'overlapping jib' or the Genoa jib, being named after the city of Genoa as explained below. It is a type of large jib or staysail used on bermuda rigged craft that overlaps the main sail, sometimes eliminating it. It is used on single-masted...
and a spinnaker
Spinnaker
A spinnaker is a special type of sail that is designed specifically for sailing off the wind from a reaching course to a downwind, i.e. with the wind 90°–180° off the bow. The spinnaker fills with wind and balloons out in front of the boat when it is deployed, called flying. It is constructed of...
. It is asymmetric like a genoa, but the gennaker is not attached to the forestay
Forestay
On a sailing vessel, a forestay, sometimes just called a stay, is a piece of standing rigging which keeps a mast from falling backwards. It is attached either at the very top of the mast, or in fractional rigs between about 1/8 and 1/4 from the top of the mast. The other end of the forestay is...
like a jib or genoa. The gennaker is rigged like a spinnaker but the tack
Parts of a sail
In sailing the parts of a sail have common terminology for each corner and edge of the sail.-The corners:In a triangular sail, the upper point is known as the head; the halyard, the line which raises the sail, is attached to the head...
is fastened to the hull or to a bowsprit
Bowsprit
The bowsprit of a sailing vessel is a pole extending forward from the vessel's prow. It provides an anchor point for the forestay, allowing the fore-mast to be stepped farther forward on the hull.-Origin:...
. It has greater camber
Camber (aerodynamics)
Camber, in aeronautics and aeronautical engineering, is the asymmetry between the top and the bottom surfaces of an aerofoil. An aerofoil that is not cambered is called a symmetric aerofoil...
than a genoa (but significantly less camber than a spinnaker). This is optimal for generating lift at larger angles of attack. An early form of gennaker was the "gollywhomper", used briefly in the 1870s.
The gennaker is a specialty sail primarily used on racing
Racing
A sport race is a competition of speed, against an objective criterion, usually a clock or to a specific point. The competitors in a race try to complete a given task in the shortest amount of time...
boats to bridge the performance gap between a genoa and a spinnaker. It is sometimes the only downwind sail on board because it is easier to use and less expensive than a spinnaker. Due to its geometry, the sail is less prone to collapsing than a spinnaker. The differences that distinguish a gennaker from an asymmetric spinnaker are blurry; they are both high camber downwind sails. One difference is the amount of camber, which dictates the points of sail. A gennaker is optimal for a beam reach
Points of sail
Points of sail describes a sailing boat's course in relation to the wind direction.There is a distinction between the port tack and the starboard tack. If the wind is coming from anywhere on the port side, the boat is on port tack. Likewise if the wind is coming from the starboard side, the boat...
, while an asymmetric spinnaker is optimal for a broad reach
Points of sail
Points of sail describes a sailing boat's course in relation to the wind direction.There is a distinction between the port tack and the starboard tack. If the wind is coming from anywhere on the port side, the boat is on port tack. Likewise if the wind is coming from the starboard side, the boat...
or run
Points of sail
Points of sail describes a sailing boat's course in relation to the wind direction.There is a distinction between the port tack and the starboard tack. If the wind is coming from anywhere on the port side, the boat is on port tack. Likewise if the wind is coming from the starboard side, the boat...
.