 |
|
| ||||||||||||||||||||||||||
|
|
| ||||||||||||||||||||||||||
|
|
|
|
|
| ||||||||
Sailing is motion across a body of water in a sailing ship, or smaller boat, powered by wind.
The force of the wind is used to create motion by using one or more sails. The movement of the air over the sails acts in the same way that air moves over an aircraft's wing. The pressure difference created on either side of the sail(s) produces a driving force.
Sailboats also have a keel or centerboard, a structure whose broad, thin shape resists lateral movement of the hull while offering little resistance to forward motion through the water. Without such a structure, sailing upwind or across the wind is impossible.
Today, for most people, sailing is a hobby.
Sailing can be further divided into two areas: Racing and Cruising.
In ancient times (see Odysseus), ships used following or rear-quarter winds. They therefore had to wait in port or at sea for the right wind directions.
First see the notes on points of sail which introduce some important principles.
There are four basic maneuvers a sailing boat can perform while underway. They are:
An important aspect of sailing is keeping the boat in "trim". To achieve this a useful mnemonic (memory aid) is the phrase.
Can This Boat Sail Correctly?
This helps the crew to remember these essential points;
By linking together a series of 'close-hauled' legs it is possible for the boat to make an upwind course. In between in each leg the boat 'tacks' through the 'no go zone'.
An important safety aspect of sailing is to adjust the amount of sail to suit the wind conditions. As the wind speed increases the crew should progressively reduce the amount of sail. On a small boat with a jib and mainsheet this is done by furling in the jib and by partially lowering the mainsail (this is called 'reefing').
As noted above, sail trimming is a large subject. Basic control of the mainsail consists of setting the sail so that it is at an optimum angle to the wind,(i.e. no flapping at the front, and tell tales flowing evenly off the rear of the sail).
Two or more sails are frequently combined to maximise the smooth flow of air. The sails are adjusted to create a smooth laminar flow over the sail surfaces. This is called the "slot effect". The combined sails fit into an imaginary aerofoil outline, so that the most forward sails are more in line with the wind, whereas the more aft sails are more in line with the course followed. The combined efficiency of this sail plan is greater than the sum of each sail used in isolation.
More detailed aspects include specific control of the sail's shape, e.g.:
See this detailed information on and then
When a boat rolls over to one side under wind pressure, it's called 'heeling'. As a sailing boat heels over beyond a certain angle, it begins to sail increasingly inefficiently. Several forces can counteract this movement.
Most of the above effects can be used to right a heeling boat and to keep the boat sailing efficiently: if however the boat heels beyond a certain point of stability, it can capsize.
How close a boat can sail to the wind depends on the wind speed, since what the boat "sees" is the apparent wind, i.e., the vector sum of the actual wind and the boat's own velocity. The apparent wind is what the windex on top of the mast shows. Because of this, people often talk about how close a boat can sail to the apparent wind. A good, modern sloop can sail within 25 degrees of the apparent wind. An America's Cup racing sloop can sail within 16 degrees, under the right conditions. Those figures might translate into 45 degrees and 36 degrees relative to the actual wind. The angles at which the wind meets the boat are described by the points of sail.
First and foremost:
Sailing is intrinsically dangerous, since water is not our natural element. All sailors therefore should take precautions, and when engaged in publicly organised activities they must take certain precautions, as detailed by the authority which regulates the training or racing.
Safety measures include:
Also, know the 'rules of the road':
Sailing boats can have one, two, or three hulls. Boats with one hull are known as monohulls, while those with two or more are known as multihulls. Multihulls can be further subdivided into catamarans (two hulls), and trimarans (three hulls). A Sailing boat is turned by a rudder which itself is controlled by a tiller or a wheel. Smaller sailing boats often have a stabilising, raisable, underwater fin called a centreboard (or daggerboard); larger sailing boats have a fixed (or sometimes canting) keel. As a general rule, the former are called dinghies, the latter yachts. (see Dinghy sailing)
The "mainsail" or "main" is usually the primary driving sail, triangular in shape, and fixed to the largest mast on the boat. A headsail, either a "jib" or "genoa", is placed in front of the mainsail, attached in such a way that the trailing edge extends back alongside the main. This is also known as an overlapping headsail (pronounced hedsal). Two or more headsails can be used. In addition, some sailboats, so-called ketches and yawls, have another sail near the back of the boat attached to a smaller mast called the "mizzen mast".
A 'spinnaker' is a very large sail that is only used when sailing downwind, to catch the maximum amount of wind.
Sailors use many traditional nautical terms for the parts of or directions on a vessel; starboard (right), port (left), forward or fore (front), aft (rearward), bow (forward part of the hull), stern (aft part of the hull). Vertical spars are masts, horizontal spars are booms (if they can hit you), gaffs (if they're too high to reach) or poles (if they can't hit you).
Actually, only a few of the "ropes" on a boat are called ropes.
Ropes or wires that hold up masts are collectively known as standing rigging and are called shrouds or stays. (The one from the mast to the bow is usually called the "fore stay", and side ones are usually referred to as just "shrouds".)
Ropes or wires that control the sails are known collectively as running rigging. Those that raise and lower sails are called halyards. Ropes that adjust (trim) the sails are called sail-plan.
Sailing terms have entered popular language in many ways. "Broken up" was the fate of a ship that hit a "rocky point." "Pooped" refers to the aftermost deck of a ship, taken from "puppis" the Latin word for "stern". "In the doldrums" referred to being becalmed, windless, especially in the narrow band of hot windless water "the doldrums", near the equator. "Adrift" meant literally that a ship's anchor had come loose, and the ship was out of control near land and therefore in serious danger. "Keel-hauled and hung out to dry." was the rather nasty process of attaching a sailor to a rope, and drawing him under the sailboat while underway, and then hanging him from a yard-arm (under his shoulders usually, not by his neck), where officers and crew could mock him. Often, the barnicles on the hull would cause lacerations, making this a particularly unpleasant punishment.
Sailors are expected to know the essentials of boating safety which include;
There are many, more esoteric, etiquette rules, traditions, and customs that will demonstrate to others advanced knowledge of boating protocol such as; pulling up the fenders when you're not in port, the use of flags.
Sail, Yachting, ketch, sail-plan, cat boat and sloop, Catamaran, Dinghy sailing, Dinghy racing, Yacht racing, Day sailer, Planing (sailing).
|
||||
| View Live Article | This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License | |
||
