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Sail-plan

From Wikipedia, the free encyclopedia

Sailing frigate and its rigging

A sail-plan is a set of drawings, usually prepared by anaval architect. It shows the various combinations of  sailproposed for a sailing ship.

The combinations shown in a sail-plan almost always include three configurations:

A light air sail plan. Over most of the Earth, most of the time, the wind force is Force 1 or less. Thus a sail plan should include a set of huge,

lightweight sails that will keep the ship underway in light breezes.

A working sail plan. This is the set of sails that are changed rapidly in variable conditions. They are much stronger than the light air sails, but

still lightweight. An economical sail in this set will include several sets of reefing ties, so the area of the sail can be reduced in a stronger 

wind.

A storm sail plan. This is the set of very small, very rugged sails flown in a gale, to keep the vessel under way and in control.

In all sail plans, the architect attempts to balance the force of the sails against the drag of the underwater  keel in such a way that the vessel

naturally points into the wind. In this way, if control is lost, the vessel will avoid broaching (turning edge-to-the wind), and being beaten by

breaking waves. Broaching always causes uncomfortable motion, and in a storm, the breaking waves can destroy a lightly-built boat.

The architect also tries to balance the wind force on each sail plan against a range of loads and ballast. The calculation assures that the sail

will not knock the vessel sideways with its mast in the water, a capsize and possible sinking.

Contents

 [hide]

• 1 Terminology

o 1.1 Types of sail

o 1.2 Order 

o 1.3 Material 

o 1.4 Ropes

o 1.5 Rigging

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1.5.1 Sprit 

and stays

• 2 Types of ships

• 3 Sail-plan measurements

• 4 See also

• 5 Notes

• 6 Further reading

• 7 External links

[edit]Terminology

[edit]Types of sail

A fore and aft sail is one that, when flat, runs fore and aft. These types of sails are the easiest to manage, because they often do

not need to be relaid when the ship changes course.

A gaff rigged  sail is a fore-and-aft sail shaped like a truncated triangle the upper edge of which is made fast to a spar called a gaff.

The top of the gaff rigged sail tends to twist away from the wind reducing its efficiency when close-hauled. However, due to the gaff on

the top edge of the sail the center of effort is typically lower, somewhat reducing the angle of heel (leaning of the boat caused by wind

force on the sails) compared to a similar sized Bermuda rigged sail.

A square sail is set square to the mast from a yard , a spar running transversely in relation to the hull (athwartships). It is not, as

commonly thought, named after the approximate shape of the sail, it is named for the square angle between the sail and the mast. In

the olden days design of a square rigger, sailors would have to climb the rigging and walk out on "footropes" under theyard to furl and

unfurl the sails. In a modern square rigged design the crew can furl and unfurl its sails by remote control from the deck. Some cruising

craft with fore-and-aft sails will carry a small square sail with top and bottom yards that are easily rigged and hauled up from the deck

(not requiring climbing the mast); such a sail is used as the only sail when running downwind under storm conditions, as the vessel

becomes much easier to handle than under its usual sails, even if they are severely reefed (shortened).

A lateen sail is a triangle with one or two sides attached to a wooden pole. This is one of the lowest drag (the sailing term

is windage) sails, and it is not easy to manage.

A Bermuda or Marconi sail is a triangular sail with one point going straight up.

A staysail ("stays'l") is a piece of cloth that has one or two sides attached to a stay , that is, one of the ropes or wires that helps

hold the mast in place. A staysail was classically attached to the stay with wooden or steel hoops. Sailors would test the hoops by

climbing on them.

A  jib is a staysail that flies in front of the foremost vertical mast.

A spanker  is a gaff-sail flown on the mizzenmast of a tall ship. For ease of handling in large sail plans, these sails would

sometimes be split into lower and upper spankers.

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[edit]Order 

Names of square rigs

Names of studding sails.

The standard terminology assumes three masts, from front to back, the fore-mast, main-mast and mizzen-mast. On ships with fewer than

three masts, the tallest is the main-mast. Ships with more masts number them.

From bottom to top, the sails of each mast are named by the mast and position on the mast, e.g. for the mainmast, from lowest to highest:

main course, main topsail, maintopgallant ("t'gallant"), main royal, main skysail, and mainmoonraker . Since the early twentieth century, the

topsails and topgallants are often split into a lower and an upper sail to allow them to be more easily handled.

On many warships, sails above the fighting top (a platform just above the lowest sail) were mounted on separate masts ("topmasts" or 

"topgallant masts") held in wooden sockets called "tabernacles". These masts and their stays could be rigged or struck as the weather and

tactical situation demanded.

In light breezes, the working square sails would be supplemented by studding sails ("stuns'l") out on the ends of the yardarms. These were

called as a regular sail, with the addition of "studding". For example, the main top studding sail .

The staysails between the masts are named from the sail immediately below the highest attachment point of the stay holding up the staysail.

Thus, the mizzen topgallant staysail can be found dangling from the stay leading from above the mizzen (third) mast's topgallant sail to some

place (usually two sails down) on the second (main) mast.

The jibs, staysails between the first mast and the bowsprit were named (from inner to outer most) fore topmast staysail (or foretop stay),

inner jib, outer jib and flying jib. All of the jib's stays meet the foremast just above the fore topgallant. Unusually, a fore royal staysail may also

be set.

[edit]Material

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Sails were classically made of hemp or  cotton. They are now made from polyesters (Dacron andPET film), sometimes reinforced

with crystalline hydrocarbons (Kevlar  and Spectra). Some large, lightweight sails are made of polyamides (nylon).

[edit]Ropes

Ropes were classically made of  manila, cotton, hemp, or  jute; papyrus (in ancient Egypt) and coir have also been seen. They are now made

of  stainless steel (301), galvanized steel, polyester (Dacron), polyamides (nylon), and sometimes crystallized hydrocarbons

(Kevlar  and Spectra).

[edit]Rigging

Standing rigging does not change position. Usually it braces the masts.

Running rigging is used to adjust sails and anchors.

A line is a rope that has been put to use aboard a sailing vessel.

A stay is a wire or rope that supports a mast. It is part of the standing rigging, usually located in the fore-aft plane of the vessel.

A shroud is similar to a stay, but is located in the athwartship plane of the vessel. Thus, shrouds come down to the sides of the

boat and are attached to chainplates.

A vang is a rope used to pull something around or down.

A boom vang  pulls down on a boom.

A sheet  is a line used to adjust the position of a sail so that it catches the wind properly.

Halyards are the lines on which one pulls to hoist something; e.g. the main-topgallant-staysail-halyard would be the line on which

one pulls to hoist (unfurl) the main-topgallant-staysail.

A block  is the seaman's name for a pulley-block. It may be fixed to some part of the vessel or spars, or even tied to the end of a

line.

The sheave is the wheel within a block, or a spar, over which a line is rove.

A fiddle block has two or more sheaves in one block, each with its own axle, so the sheaves are aligned.

A snatch-block can be closed around a line, to grab the line, rather than threading the end of the line through the block.

A shackle is a piece of metal to attach two ropes, or a block to a rope, or a sail to a rope. Customarily, a shackle has a screw-

in pin which often is so tight that a shackle-key must be used to unscrew it. A snap-shackle does not screw, and can be released by

hand, but it is usually less strong or more expensive than a regular shackle.

Running lines are made fast (unmoving) by belaying them to (wrapping them around) a cleat or abelaying-pin located in a pin-

rail or fife-rail .

[edit]Sprit and stays

Bowsprit  , a horizontal spar extending from the bow (front) of the boat used to attach the forestay to the foremost mast

Bobstays, a pair of stays on either side of the bowsprit bracing it against lateral forces

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martingale, a heavy stay directly below the bowsprit, often the strongest on a ship, frequently made of chain. Between the

bowsprit and the martingale ran a heavy pole to provide tension known colloquially as the dolphin striker .

The stays on a ship roughly form hoops of tension holding the masts up against the wind. Many ships have been "tuned" by tightening the

rigging in one area, and loosening it in others. The tuning can create most of the stress on the stays in some ships.

[edit]Types of ships

Sailboat types may be distinguished by:

hull configuration (monohull, catamaran, trimaran),

keel type (full, fin, wing, centerboard etc.),

purpose (sport, racing, cruising),

number and configuration of masts

sail plan (square and/or fore and aft rigged sails).

Sloop: a Bermuda or gaff  mainsail lifted by a single mast with a single  jib bent onto theforestay, held taut with a backstay. The

mainsail is usually managed with a spar  on the underside called a "boom". One of the best-performing rigs per square foot of sail area

and is fast for up-wind passages. This rig is the most popular for recreational boating because of its potential for high performance. On

small boats, it can be a simple rig. On larger  sloops, the large sails have high loads, and one must manage them with winches or 

multiple purchase block-and-tackle devices.

Cutter : like a sloop with two or more headsails in the foretriangle. Better than a sloop for light winds, it is also easier to manage,

due to the sail area being split up between smaller sails which require less force to trim as compared to the larger single jib of the sloop.

The mast is located at about 50% of boat length.

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 Yawl : like a sloop or catboat with a mizzen mast located aft (closer to the stern of the vessel) of the rudder post. The mizzen is

small, and is intended to help provide helm balance.

Ketch: like a yawl, but the mizzenmast is often much larger, and is located forward of the rudder post. The purpose of the mizzen

sail in a ketch rig, unlike the yawl rig, is to provide drive to the hull. A ketch rig allows for shorter sails than a sloop with the same sail

area, resulting in a lower center of sail and less overturning moment. The shorter masts therefore reduce the amount of ballast and

stress on the rigging needed to keep the boat upright. Generally the rig is safer and less prone to broaching or capsize than a

comparable sloop, and has more flexibility in sailplan when reducing sail under strong crosswind conditions—the mainsail can be

brought down entirely (not requiring reefing) and the remaining rig will be both balanced on the helm and capable of driving the boat.

The ketch is a classic small cargo boat.

Catboat: a sailboat with a single mast and single sail, usually gaff-rigged. This is the easiest sail-plan to sail, and is used on the

smallest and simplest boats. The catboat is a classic fishing boat. A popular movement among home-built boats uses this simple rig to

make "folk-boats." One of the advantages of this type is that it can be rigged with no boom to hit one's head or knock one into the

water. However, the gaff requires two halyards and often two topping lifts. The weight of the gaff spar high in the rigging can be

undesirable. The gaff's fork (jaws) is held on by a rope threaded through beads called truck s (US) or   parrel beads (UK). The gaff must

slide down the mast, and therefore prevents any stays from bracing the mast. This usually makes the rig even heavier, requiring yet

more ballast.

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Gunter : a rig designed for smaller boats where the mast is often taken down. It consists of a relatively short mast (usually slightly

shorter than the boat so that it can be stowed inside) and a long gaff (often only slightly shorter than the mast). However, rather than

the usual trapezoidal shape of a gaff sail, it is triangular, like a Bermuda rig. This allows the gaff, when hoisted, to pivot upwards until it

is vertical, effectively forming an extension to the mast. Thus a decent-sized sailing rig can be added to the boat while still allowing all

the equipment to be stowed completely inside it. The popular Mirror class of dinghy is gunter rigged for this reason.

Schooner : a fore-and-aft rig having at least two masts, with a foremast that is usually smaller than the other masts. Schooners

have traditionally been gaff-rigged and in small craft are generally two-masted, however many have been built with Marconi rigs (and

even junk rigs) rather than gaffs and in the golden age of sail, vessels were built with as many as seven masts. One of the easiest

types to sail, but performs poorly to windward without gaff topsails. The extra sails and ease of the gaff sails make the rig easier to

operate, though not necessarily faster, than a sloop on all points of sail other than up-wind. Schooners were more popular than sloops

prior to the upsurge in recreational boating. The better performance of the sloop upwind was outweighed for most sailors by the better 

performance of the schooner at all other, more comfortable, points of sail. Advances in design and equipment over the last hundred

years have diminished the advantages of the schooner rig. Many schooners sailing today are either reproductions or replicas of famous

schooners of old.

Brig: two masts, both square-rigged with a spanker on the mainmast.

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Brigantine: two masts, square-rigged on the foremast and fore-and-aft rigged on the mainmast.

Barquentine: is a three masted vessel, square rigged on the foremast and fore-and-aft rigged on the main and mizzen masts.

Some sailors who have sailed on them[who? ] say it is a poor-handling compromise between a barque and a ship, though having more

speed than a barque or schooner.

Barque: three masts or more, square rigged on all except the aftmost mast. Usually three or four masted but five masted barques

have been built. Lower-speed, especially downwind, but requiring fewer sailors than a ship. This is a classic slow-cargo ship.

Fully rigged Ship: three or more masts, square rigged on all, with stay-sails between. The classic ship rig originally had exactly

three masts, but four and five masted ships were also built. The classic sailing warship—the ship of the line—was fully rigged in this

way, because of high performance on all points of wind. They were larger than brigs and brigantines, and faster than barques or 

barquentines, but required more sailors.

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Bragana or  felucca: a classic in the Mediterranean or Indian Ocean. Three lateen sails in a row.

Polacre: a three master with a narrow hull; carrying a square-rigged foremast, followed by two lateen sails. The same vessel, if 

she substituted her square-rigged mast with another lateen rigged one, would be called a xebec.

Junk: the standard Chinese design: The sails are made flat with bamboo inserts (battens), permitting them to sail well on any

point of sail. Easy to sail, and reasonably fast. The nature of the rig places no extreme loads anywhere on the sail or rigging, thus can

be built using light-weight, less expensive materials. Some of the largest sailing ships ever constructed were junks for the

Chinese treasure fleets. Junks also customarily had internal water-tight rooms, kept so by not having doors between them. Usually they

were constructed of  teak or mahogany.

[edit]Sail-plan measurements

Sloop rig sail-plan measurements

Every sail-plan has maximum dimensions [1][2]. These maxima are for the largest sail possible and they are defined by a letter abbreviation.

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J The base of the foretriangle measured along the deck from the forestay pin to the front of the mast.

I The height measured along the front of mast from the jib halyard to the deck.

E The foot length of the mainsail along the boom.

P The luff length of the mainsail measured along the aft of the mast from the top of the boom to the highest point that the mainsail

can be hoisted at the top of the mast.

Ey The length of a second boom (For a Ketch or Yawl).

Py The height of the second mast from the boom to the top of the mast.