Fore-and-aft rigs comprise the vast majority of sailing vessels in use today, including effectively all
dinghies and
yachts. The sheet on a fore-and-aft sail controls the angle of the sail to the wind, and should be adjusted to keep the sail just filled. Most smaller boats use the
Bermuda rig, which has two or three sets of sheets: • The
mainsheet is attached to the boom, and is used to control the
mainsail. In a rig with no boom on the
mainsail, the mainsheet would attach directly to the mainsail
clew. A mainsheet is a line connected to the boom which allows a sailor to control the speed of a boat. • The
jib sheet attaches to the clew of the
jib, and controls it. The jib has a sheet on each side, only one of which (the leeward one) will be in use at one time. • The
spinnaker sheet attaches to the clew(s) of the
spinnaker, if carried. A symmetrical spinnaker has two sheets, an "active" one and a "lazy" one, in the same way as a jib, but they are attached to the sail's two separate clews. On boats larger than around thirty feet, the spinnaker will also be fitted with
guys, which are similar to sheets but control the pole instead of the sail. On smaller boats the lazy sheet is used as a guy. On the smallest boats, a sheet is often a simple line, pulled by hand; on larger boats, intermediate
blocks are sometimes used to provide
mechanical advantage. However, many blocks and their multiply reeved lines, particularly on headsails, have been replaced by single-line sheets trimmed by powerful
winches. == Square rig ==