, right. The foretriangle is outlined in red. Boats may be sailed using a jib alone, but more commonly jibs make a minor direct contribution to propulsion compared to a
main sail. Generally, a jib's most crucial function is as an
airfoil, increasing performance and overall stability by reducing
turbulence on the main sail's
leeward side. On boats with only one jib, it is common for the
clew of the jib to be abaft the mast, meaning the jib and mainsail overlap. An overlapping jib is called a
genoa jib or simply a
genoa (see illustration). These are efficiently used when
reaching more broadly than a
close reach. Alternatively, a boat may carry smaller jibs, to compensate aerodynamics when the main sail is
reefed; these more rugged sails are called
storm jibs or
spitfires. On a boat with two
staysails the inner sail is called the
staysail, and the outer (foremost) is called the jib. This combination of two staysails is called a
cutter rig (or in North America a
yankee pair) and a boat with one mast rigged with two staysails and a mainsail is called a
cutter. On cruising yachts, and nearly all racing sailboats, the jib needs to be worked when tacking. On these yachts, there are two sheets attached to the
clew of the jib. As the yacht comes
head to wind during a tack, the active sheet is released, and the other sheet (the
lazy sheet) on the other side of the boat is pulled in. This sheet becomes the new
active sheet until the next tack. ==Traditional vessels==