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For the military definition of sloop see: Sloop-of-war.
File:Sail plan sloop.svg
The sail plan of a typical sloop, with a gaff rig on the mainsail
For the open learning project see: SLOOP Project.

A sloop (from Dutch sloep) is a sail boat with a fore-and-aft rig and a single mast farther forward than the mast of a cutter. A sloop's fore-triangle is smaller than a cutter's, and unlike a cutter, a sloop usually bends only one headsail, though this distinction is not definitive; some sloops such as the Friendship Sloop have more than one. Ultimately the position of the mast is the most important factor in determining whether a ship is classified as a sloop.[citation needed]

On a gaff rigged, single masted boat, the clearest distinction between a sloop and a cutter is the run of the forestay. On the sloop, it runs to the outboard end of the bowsprit, which means that the bowsprit must always stay in position and cannot be retracted. On a cutter, the forestay runs to the stem head of the hull. This allows the bowsprit to be run back inboard and stowed. This can be helpful in crowded harbours or when stowing the jib in strong wind conditions.[citation needed]

Rationale behind the sloop rig

No design is perfect for all conditions; sloops are designed to optimize upwind sailing. However, sloops also offer an excellent overall acceptable compromise, if not optimal, to all points of sail. It is clear that the most difficult direction to sail is to the windward (known as sailing close-hauled); this requires some specific design features. The sail should be as vertical as possible to optimize the energy of the wind.

Two forces act on a vessel to push it from vertical (also known as heeling over): (1) the weight of the rig itself will tend to heel the boat, and (2) the sideways force of the wind on the sails. The sloop is a light rig with fewer lines and spars, and the sails on a sloop tend to be flat which minimizes sideways force when well trimmed. The heeling forces are also counterbalanced by the keel, which uses weight and hydrodynamics to offset the forces from the rigging and sails.

When sailing upwind, it is also important to minimize the drag of the wind on the sail and rig. A major cause of drag of the sail is a vortex of turbulent air generated by the top of the mast and sail. Secondary causes are non-optimal aerodynamic shapes of masts, stays and control lines. The sloop minimizes the drag of the tip-vortex with a high and narrow sail design (high aspect), maximizing the amount of sail for a given tip-vortex compared to a square-rigged or gaff-rigged ship. Also, the simplicity of the rig reduces the drag induced by control lines, masts and spars.

Sails carried

A sloop-rigged J/24 sailboat

To maximize the amount of sail carried, the classical 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 as much as 55 to 100 percent for racing rules and sometimes more. The mainsail and Genoa form an efficient double wing.

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 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 largest difference being that these ships were built on the shores of Jamaica. The keel for Jamaica sloops would be usually between 50-75 feet, but could be built longer. They usually had a speed of around 12 knots, which is equivalent to about 13 mph.[1] 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[2] One of the reasons why Jamaican sloops were built out of cedar and not oak, was because of the specific properties of cedar. The oak that would normally be used would rot in about 10 years while cedar would last for close to 30 and was considerably lighter than oak.[2] The change in weight also made the ships made of cedar faster and able to maneuver quicker. Pirates found these ships very beneficial because they were able to sail in shallow areas where larger ships would either run aground or be unable to sail through at all. When the ship had to be careened, Pirates needed a safe haven in order to ground the ship. The shallow areas provided great protection from many of the naval ships of the English, since those tended to be larger and unable to safely sail in the shallow waters.[2] Since piracy was a nuisance in Caribbean waters, merchants sought ships that could be easily defended. The irony about these ships, though, is that, although the ships were needed to be fast and maneuverable in order to avoid pirates, if one of these ships was captured, that speed and maneuverability would be in the hands of the pirates.

Historic naval definition

File:Royal Navy - Bermuda Sloop.jpeg
A three-masted Bermuda sloop of the Royal Navy, ca. 1831. Also called Ballyhou schooners, the RN referred to these as sloops-of-war.

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 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 Royal Navy began buying Bermuda sloops, beginning with an order for three sloops-of-war (HMS Dasher, HMS Driver, and HMS Hunter, 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 the 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 a corvette.

Modern naval definition

In modern use, 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 [1], for numerous roles, including escort duty and anti-submarine warfare, during the Great War. The same was true during the Second World War, when the Royal Navy used the Black Swan class, but for many years, now, its smallest warships have been frigates (not including fishery patrol vessels and offshore patrol vessels, like the Peacock Class [2]).

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 take 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 rule. Much faster sloops have been built that do not fit the rule, 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.

The largest yachting sloop built to date is Mirabella V, with a carbon-fiber mast that is 289 feet (90 m) high.

See also


  1. Konstam, Angus. 2007. Pirates: Predators of the Seas. 23–25.
  2. 2.0 2.1 2.2 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 & Shuster, 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 & Shuster, 1987

External links

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