Add to your Kayak Sailor rig! The Genoa is used to maximize overall sail area, a benefit in light winds. This makes the sail system faster and more powerful not only because of the increased overall sail area but because of the synergistic relationship between the two sails.
When pointing close to the wind a properly designed and trimmed head sail allows the main sail to work at a higher angle to the wind without stalling, making reaches to windward more effective. The Genoa has a low center of effort, to minimize heeling.
A headsail is commonly referred to as a jib or a Genoa (named for the city in Italy). The main difference between a jib and a genoa (or jenny) is the overall sail size and its position in relation to the main sail. A genoa is larger than a jib and overlaps the mast with its leech when close hauled. The Foot (or base) is 29 inches. The Luff (leading edge fastened to the Forestay) is 46 inches. The Leach (trailing edge) is 40 inches.