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 backstays, 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.