Sloop
For the military definition of sloop see:Sloop-of-war. |
A sloop-rigged J-24 sailboat |
A
sloop (From
Dutch sloep) in
sailing, is a vessel with a
Fore-and-aft rig. A sloop carries a single
mast stepped farther forward than that of a
cutter. The sloop's fore-triangle is smaller than a cutter's. As such, the sloop usually bends only one headsail, though this distinction is not definitive. A cutter rig generally carries multiple headsails, however sloops such as the
Friendship Sloop carry more than one headsail and are properly designated a sloop and not a cutter. Ultimately position of the mast is the most important factor.
The modern yachting sloop is known as the
marconi sloop or bermuda sloop, 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 reasonable downwind speed in all but the strongest winds, and the spinnaker is an intrinsically unstable sail requiring continual trimming.
|
Typical marconi rigged sloop |
No design is perfect for all conditions; sloops are designed to optimise upwind sailing. However, sloops also offer an excellent overall compromise acceptable, 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.
To maximize the amount of sail carried, the classical sloop may use a
bowsprit, which is essentially a fixed spar that projects forward from the bow of the boat. For downwind sailing, the typical
foresail may be replaced (or sometimes supplemented) by larger sails know as
spinnakers or
gennakers. The typical
foresail known as the
jib, which does not overlap the mast, may be replaced by a
genoa jib, which overlaps the mast by up to 55% for racing rules and sometims more. The mainsail and Genoa forman efficient double wing.
Historic/Military Definition
The military 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. Generally a sloop was smaller than a frigate; however, in the later days of the US Navy's sailing fleet, some of the largest vessels were called sloops because they carried fewer guns than a frigate (less than 20) and the mission was that of a sloop (vague). The classification of sloop was similar to a
corvette.
Modern/Yachting Connotation
Sloops in their modern form were developed by the
French to run
British 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.
In the
1920s, racing sloops were developed into extremes in the amount of sail they would carry. The "J-boats" became infamous for capsizing, although in good weather they were very fast. These excesses led racing authorities to establish rules for racing yachts, intended to make them fully seaworthy. The first modern sloops were called "Marconi rigs" because their tall masts and complex standing rigging reminded people of Guglielmo Marconi's new wireless (radio) transmission antennas; this is also known as a
Bermuda Rig.
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 don't 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 hr distance record was recently broken several times, with ABN AMBRO 2 setting the record distance of 563 nautical miles for a monohull (Jan 2006). These boats routinely sail at or above wind speeds and can sustain mid-20 knot speeds hour after hour.
The largest yachting sloop built to date is the
Mirabella V, with a
carbon-fibre mast that is 289 ft/90 m high.
*
Sailboat *
Bermuda rig, also called a Marconi rig, the most common of the sloop rigs.
*
Friendship Sloop, a traditional
gaff-rigged sloop developed for the
Maine lobster fishery.
*
Sloop John B, a traditional song about an ill-fated trip on the eponymous vessel, made famous by the Beach Boys.
*
Hudson River Sloop Clearwater, A traditional sloop launched in 1969 to promote environmental awareness.
