- For the military definition of sloop see: Sloop-of-war.
- For the open learning project see: SLOOP Project.
A sloop (from Dutch sloep, in turn from French chaloupe) is a sail boat with a single mast and a fore-and-aft rig. In the USA a sloop may have one, two or three head-sails forward of the mast—the term cutter not generally being used for sailboats. In the rest of the English speaking world, a sloop has only one head-sail and if a vessel has two or more head-sails, she is termed a 'cutter' and her mast may be set further aft than on a sloop.
The commonest rig of modern sailboats is the Bermuda sloop. Typically, a modern sloop carries a mainsail on a boom aft of the mast, with a single loose-footed head-sail (a jib or a genoa jib) forward of the mast.
Sloops are either masthead-rigged or fractional-rigged. On a masthead-rigged sloop, the forestay (on which the headsail is carried) attaches at the top of the mast. The mainsail may be smaller than the headsail, which is then called a genoa jib. On a fractional-rigged sloop, the forestay attaches to the mast at a point below the top, typically 3/4 of the way to top, or perhaps 7/8 or some other fraction. The mast of a fractional-rigged sloop may be placed farther forward, and compared to a masthead-rigged sloop, this results in a rather smaller jib relative to the size of the mainsail.
Rationale behind the sloop rig 
After the cat rig, which has only a mainsail, the sloop rig is one of the simpler sailing rig configurations. A sloop typically has two sails, a mainsail and a jib; while the cutter has a mainsail and two foresails. Next in complexity are the ketch, the yawl, and the schooner, each of which has two masts and a minimum of three sails. A sloop has a simple system of mast stays—a forestay, backstay, and sidestays.
By having only two sails, the individual sails of a sloop are larger than those of an equivalent cutter, yawl or ketch. Until the advent of lightweight sailcloth and modern sail-handling systems, the larger sails of a sloop could be a handful. So, until the 1950s, sailboats over 10 metres LOA would typically use a cutter rig or a two-mast rig. After the advent of modern winches and light sailcloth, the sloop became the dominant sailing rig type for all but the largest sailboats.
No rig type is perfect for all conditions. Sloops, with their paucity of spars and control lines tend to impart less aerodynamic drag. Compared to other rigs, sloops tend to perform very well when sailing close hauled to windward; and sloops offer a sound overall compromise of abilities on all points of sail. Cutters and ketches and yawls are often still preferred to sloops when venturing far offshore, because it is easier to reef small sails, as the wind increases, while still keeping the boat balanced.
Sails carried 
To maximize the amount of sail carried, the classic sloop may use a bowsprit, which is essentially a spar that projects forward from the bow of the boat. For downwind sailing, the typical foresail may be replaced (or sometimes supplemented) by larger curved sails known as spinnakers or gennakers. The typical foresail, known as the jib, which does not overlap the mast more than 10 to 20 percent, may be replaced by a genoa, which overlaps the mast by some 55 to 100 percent, for racing rules, and sometimes even more. The genoa's large overlap behind the mainsail helps to guide the airflow and thereby makes the mainsail more effective.
The Bermuda Sloop 
The modern yachting sloop is known as the Bermuda sloop, due to its Bermuda rig (also known as the Marconi rig, due to its resemblance to the wireless towers of Guglielmo Marconi), which is the optimal rig for upwind sailing; consequently sloops are popular with sport sailors and yachtsmen, and for racing. The rig is simple in its basic form, yet when tuned properly, it is maneuverable and fast. The main disadvantage is the relatively large size of the sails, especially on larger vessels. It is also less successful sailing downwind; the addition of a spinnaker is necessary for faster downwind speed in all but the strongest winds, and the spinnaker is an intrinsically unstable sail requiring continual trimming.
The Bermuda sloop is a type of fore-and-aft rigged sailing vessel developed on the island of Bermuda in the 17th century. In this sense, the term is applied to small ships, rather than boats. In its purest form, it is single-masted, although ships with such rigging were built with as many as three masts. Its original form had gaff rig, but evolved to use what is now known as Bermuda rig, making it the basis of nearly all modern sailing yachts. Although the Bermuda sloop is often described as a development of the narrower-beamed Jamaica sloop, which dates from the 1670s, the high, raked masts and triangular sails of its Bermuda rig are rooted in a tradition of Bermudian boat design dating from the early 17th century. Part of that tradition included long, horizontal bowsprits and large jibs. Three jibs were commonly used on Bermudian ships. Triangular sails appeared on Bermudian boats early in the 17th century, a development of the Dutch bezaan, or leg-of-mutton rig, itself derived from the Lateen rig. This became the Bermuda rig, and was appearing on Bermudian ships by the early 19th century. A large spinnaker was carried on a spinnaker boom, when running down-wind.
Jamaican sloop 
Jamaican sloops were slightly different from Bermuda sloops, the most obvious difference being that these ships were built on the shores of Jamaica. Their beams were narrower than ocean-going Bermuda sloops, and they carried gaff rig, where Bermuda sloops might carry gaff or Bermuda rig. The keel of Jamaican sloops would usually be between 50–75 feet, but could be built longer. They usually had a speed of around 12 knots, which is equivalent to about 13.8 mph. The sloops were built near the shore and usually out of cedar trees, since these were very resistant to rot, grew very fast and tall, and had a taste displeasing to animals. One of the reasons Jamaican sloops were built out of cedar, and not oak, was that oak which would normally be used would rot in about 10 years, while cedar would last for close to 30 years. Another advantage of cedar was that it was considerably lighter than oak. The lighter weight made the ships of cedar faster and more able to maneuver quickly.
Since piracy was a significant threat in Caribbean waters, merchants sought ships that could outrun pursuers. Ironically, that same speed and maneuverability made them highly prized and even more targeted by the pirates they were designed to avoid.
When the ship had to be careened, pirates needed a safe haven on which to ground the ship. Sloops were well suited for this because they were able to sail in shallow areas where larger ships would either run aground or be unable to sail through at all. These shallow waters also provided protection from many of the naval ships of the English, which tended to be larger and required deep water to sail safely.
The naval term "sloop" referred to ships with different rigs and sizes varying from navy to navy. "Sloop-of-war" was more of a reference to the purpose of the craft, rather than to the specific size or sailplan. (Further confusion was caused by the practice of redesignating a vessel simply according to the rank of the commanding officer.) The British Royal Navy began buying Bermuda sloops, beginning with an order for three sloops-of-war (HMS Dasher, HMS Driver, and HMS Hunter, which were each of 200 tons, armed with twelve 24 pounders) placed with Bermudian builders in 1795. They were intended to counter the menace of French privateers, which the Navy's ships-of-the-line were ill-designed to counter.
Eventually, Bermuda sloops became the standard advice vessels of the navy, used for communications, reconnoitering, anti-slaving, anti-smuggling, and other roles to which they were well suited. The most notable examples of these were HMS Pickle, which raced back to England with news of the British victory and the death of Admiral Lord Nelson at the end of the Battle of Trafalgar, and HMS Whiting (79 tons and four guns), which lowered anchor in the harbor of Hampton Roads on 8 July 1812, carrying dispatches. The American privateer Dash, which happened to be leaving port, seized the vessel. The crew of Whiting had not yet received news of the American declaration of war, and her capture was the first naval action of the American War of 1812.
Generally, a sloop was smaller than a frigate; however, in the later days of the U.S. Navy's sailing fleet, some of the largest vessels were called sloops because they carried fewer guns than a frigate, as few as 20. The classification of sloop was similar to that of a corvette.
In modern usage, a sloop refers to a warship between a corvette and a frigate in size. Such vessels were common during the age of steam, but ships of this type were becoming obsolete by the Second World War. The Royal Navy used sloops, such as those of the Flower class, in numerous roles, including escort duty and anti-submarine warfare, during World War I. The same was true during the Second World War, when the Royal Navy used the Black Swan class. During World War II, Royal Navy sloops destroyed five German submarines.
Modern civilian connotation 
Sloops in their modern form were developed by the French Navy as blockade runners to circumvent Royal Navy blockades. They were later adapted to pilot boats (small ships that took a pilot out to a ship, to guide it into a harbor). Later still, they were adapted to smaller revenue cutters.
The first modern sloops were fitted with the Bermuda rig, so called as a result of its development in Bermuda, during the 17th century. This rig is also called the Marconi rig because of the resemblance of its tall mast and complex standing rigging to Guglielmo Marconi's wireless (radio) transmission antennas.
The state of the art in racing sloops, today, may be seen in the IACC yachts sailed in the America's Cup competition. This statement is only true in that the most money has been spent in this class, to build the fastest boats that meet the IACC rules. Much faster sloops have been built that do not fit the rules, using such forbidden technology as canting keels and movable water ballast. The current Volvo Ocean Race is using a new class, the Volvo 70, which boasts a canting keel, carbon construction throughout, and very powerful sailplans. The 24-hour distance record was recently broken several times, with ABN AMRO 2 setting the record distance of 563 nautical miles (1,043 km) for a monohull (January 2006). These boats routinely sail at or above wind speeds and can sustain mid-20-knot (37 km/h) speeds hour after hour.
See also 
- Spray (sailing vessel), a sloop rebuilt and used by Joshua Slocum to sail single-handed around the world, the first voyage of its kind
- "Sloop John B", a traditional song about an ill-fated trip, made famous by The Beach Boys
- "Barrett's Privateers", a song written by Stan Rogers, about a sailor on the sloop Antelope
- Hudson River Sloop Clearwater, a traditional sloop launched in 1969 to promote environmental awareness
- Sloop Woody Guthrie, a sister ship to the Clearwater that helps to promote environmental awareness
- Mast aft rig, a single mast rig with a mast further back than a sloop or cutter
- Konstam, Angus. 2007. Pirates: Predators of the Seas. 23–25.
- Evans, Amanda M. 2007. Defining Jamaica Sloops: A Preliminary Model for Identifying an Abstract Concept. Journal of Maritime Archaeology, 2 (2) (October): 83–92.
- Rousmaniere, John, The Annapolis Book of Seamanship, Simon & Schuster, 1999
- Chapman Book of Piloting (various contributors), Hearst Corporation, 1999
- Herreshoff, Halsey (consulting editor), The Sailor’s Handbook, Little Brown and Company, 1983
- Seidman, David, The Complete Sailor, International Marine, 1995
- Jobson, Gary, Sailing Fundamentals, Simon & Schuster, 1987
|Wikimedia Commons has media related to: Sloops|
- Hudson River Sloop Woody Guthrie, a smaller Hudson River Ferry sloop operated by the Beacon Sloop Club
- Jones, Gregory O. The American Sailboat.