Wishbone boom
Encyclopedia
The wishbone boom on sailing
craft is most commonly seen on windsurfing
boards (sailboards).
The wishbone boom on larger sailing craft is a double-sided boom
set at an angle to the mast
and typically supported by line stays
from the leading edge of the mast to each side of the boom. The sail's foot (outhaul
) and luff (vang
) tension are adjusted simultaneously by the use of one line, called a snotter
or a choker.
The wishbone tensions the sail at an angle, pulling the sail both back and down. This trims the sail more efficiently than the forces applied to a sail with a conventional boom, with the outhaul and vang. The wishbone is also more effective at bending the carbon-fibre mast. The only way in which a conventional mast could be similarly bent is with the use of running backstay
s, which are usually only seen on pure racing boats. The disadvantages of conventional running backstays are numerous. They must be constantly trimmed by an experienced sailor, and if adjusted incorrectly, could cause catastrophic mast failure.
The wishbone boom additionally is an attachment point for lazy jack
lines to catch the sail when it is dropped for furling
or reefing
.
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...
craft is most commonly seen on windsurfing
Windsurfing
Windsurfing or sailboarding is a surface water sport that combines elements of surfing and sailing. It consists of a board usually two to four metres long, powered by the orthogonal effect of the wind on a sail. The rig is connected to the board by a free-rotating universal joint and comprises a...
boards (sailboards).
The wishbone boom on larger sailing craft is a double-sided boom
Boom (sailing)
In sailing, a boom is a spar , along the foot of a fore and aft rigged sail, that greatly improves control of the angle and shape of the sail. The primary action of the boom is to keep the foot of the sail flatter when the sail angle is away from the centerline of the boat. The boom also serves...
set at an angle to the mast
Mast (sailing)
The mast of a sailing vessel is a tall, vertical, or near vertical, spar, or arrangement of spars, which supports the sails. Large ships have several masts, with the size and configuration depending on the style of ship...
and typically supported by line stays
Stays (nautical)
Stays are the heavy ropes, wires, or rods on sailing vessels that run from the masts to the hull, usually fore-and-aft along the centerline of the vessel...
from the leading edge of the mast to each side of the boom. The sail's foot (outhaul
Outhaul
An outhaul is a line which is part of the running rigging of a sailboat, used to extend a sail and control the shape of the curve of the foot of the sail. It runs from the clew to the end of the boom...
) and luff (vang
Boom vang
A boom vang or kicking strap is a line or piston system on a sailboat used to exert downward force on the boom and thus control the shape of the sail. An older term is "martingale"....
) tension are adjusted simultaneously by the use of one line, called a snotter
Snotter
A snotter is a rope or tackle used in sailing to tension the sprit on a spritsail, or a sprit boom on a sprit-boomed sail. It is also used in a junk rig....
or a choker.
The wishbone tensions the sail at an angle, pulling the sail both back and down. This trims the sail more efficiently than the forces applied to a sail with a conventional boom, with the outhaul and vang. The wishbone is also more effective at bending the carbon-fibre mast. The only way in which a conventional mast could be similarly bent is with the use of running backstay
Backstay
On a sailing vessel, a backstay is the piece of standing rigging that runs from the mast to the transom of the boat, counteracting the forestay and jib...
s, which are usually only seen on pure racing boats. The disadvantages of conventional running backstays are numerous. They must be constantly trimmed by an experienced sailor, and if adjusted incorrectly, could cause catastrophic mast failure.
The wishbone boom additionally is an attachment point for lazy jack
Lazy jack
Lazy jacks are a type of rigging which can be applied to a fore-and-aft rigged sail to assist in sail handling during reefing and furling...
lines to catch the sail when it is dropped for furling
Furling
Furling may refer to:*Furling , characters in the series Stargate SG-1*Furl , to gather a sail*Furling , to manipulating an airfoil*The Furlings, characters in the 1993 film Once Upon a Forest...
or reefing
Reefing
Reefing is a sailing manoeuvre intended to reduce the area of a sail on a sailboat or sailing ship, which can improve the ship's stability and reduce the risk of capsizing, broaching, or damaging sails or boat hardware in a strong wind...
.