Sailing Fundamentals - Couverture souple

Jobson, Gary

Couverture souple

ISBN 10 : 0671605984 ISBN 13 : 9780671605988

Editeur : Prentice Hall & IBD, 1987

Synopsis

Book by Jobson Gary

A propos du livre

Extrait

Chapter 1
ASHORE KNOWLEDGE
ALL ABOUT BOATS
PROPULSION TYPES
Recreational boats are designed to use one or more of three propulsion types. Selfpropelled vessels, including kayaks, rowboats, rafts, and canoes, are designed to be propelled by people using paddles, oars, or poles. Power-driven vessels (powerboats) typically use gasoline or diesel motors for propulsion. Sailing vessels (sailboats) are wind powered, using sails to capture the wind's power (see below).
Powerboat -- a recreational boat typically powered by a gasoline or diesel engine. Powerboats may be subdivided into several types, including utility boats (prams, skiffs, dinghies, inflatables, and utility outboards), runabouts (bowriders, open fishermen, center consoles), cruisers (trawlers, houseboats, larger sportfishing vessels), pontoon boats, and personal watercraft (PWC). Each type has certain uses, characteristics, and limitations. Utility boats, for example, are used as tenders for larger craft and as platforms for fishing and hunting in protected waters. Because utility boats are generally small with limited stability, boaters should enter them carefully to avoid overloading. Caution should also be exercised when moving within these boats to avoid tipping them over. Runabouts are generally fast, maneuverable craft, used for fishing, hunting, cruising, and waterskiing. Cruisers are generally larger, more seaworthy (except for houseboats) craft, equipped with berths (sleeping areas), a head (marine toilet), galley (marine kitchen), and other facilities necessary for living aboard. Powerboats are subject to particular navigation rules and have specific responsibilities under those rules.
Personal Watercraft -- also called "water scooters" as well as a variety of trade names. They are highly maneuverable, fast, fun-to-operate, low-cost, power-driven (jet drive) craft capable of operation in very shallow water. Many PWC are designed for one person, but larger models are available for use by two or three people. PWC are not toys and are governed by navigation rules applicable to power-driven vessels. In addition, most states and many localities have established specific laws that regulate PWC activities, such as prohibition of night operations, speed limitations, prohibitions of specific activities (e.g., wake jumping), limitations on operator age, and education requirements. These popular craft have unique operating capabilities (e.g., high speed, shallow draft), but are also subject to limitations. For example, PWC are steered by altering (via handlebars) the direction of the jet drive, and if power is not applied, steering is lost (the so-called off-throttle steering problem). Operators who are unfamiliar with this design feature may have difficulty controlling the vessel. PWC are designed for operation in relatively calm waters, have limited fuel capacity, and are not highly stable or maneuverable at slow speeds.
PWC operators often focus their attention on nearby waves or wakes, which can impair their ability to maintain a proper lookout. Operators of other vessels should exercise caution when operating in the vicinity of PWC to minimize the likelihood of collision.
Persons using PWC can expect to be thrown into the water and should wear personal flotation devices (PFDs) suitable for PWC use. The ability to swim and knowing how to reboard a PWC from the water are also essential. Many PWC are equipped with engine kill switches rigged to shut the engine off if the riders are thrown from the craft. Fuel management is very important for PWC. Not all PWC are equipped with fuel gauges. Instead, they have reserve tanks and riders need to know how to switch to the reserve tanks and must know the PWC's endurance when using the reserve tanks. Weight and balance are important for PWC operators. Thorough familiarity with owners' manuals and strict adherence to the published limitations are essential. Finally, it is important that operators of PWC (as well as other craft) display environmental sensitivity. Operations in shallow water areas may disturb a fragile ecosystem and its inhabitants.
Sailing Vessel -- as noted above, this is a wind-powered vessel that uses only sails for power. Many sailboats are also equipped with gas or diesel motors for use (either as primary or supplemental power) when winds are light or from the wrong direction, for docking or other precise maneuvering, and for operation in waters (e.g., certain canals) where use of sails is prohibited. A sailboat is a power-driven vessel, as defined in the navigation rules, when the motor is in operation, and must observe regulations applicable to this type of vessel. When powered solely by sail, a sailboat is termed a sailing vessel and is subject to other specific regulations and (because of its limited maneuverability) enjoys certain privileges under the navigation rules. Various types of sailboat are discussed later in this text.
Sailboard -- a modified surfboard with a mast attached that holds a sail and is capable of swiveling. They are one-person craft, so the "skipper" operates the sail, steers, and acts as lookout. Visibility on these highspeed craft may be limited when the operator is positioned behind the sail. Skippers of other craft should understand this limitation and exercise caution when operating in the vicinity of sailboards.
HULL
The hull is the basic boat minus the rigging. The hull comprises the bottom, topsides, buoyancy tanks, and deck. One way to classify boats is based on hull design. Displacement-hull boats move through the water and push it aside or displace it. Planing-hull vessels move faster and, after gaining speed, ride more nearly on top of the water. All boats at rest or moving slowly are displacement boats. Each displaces a volume of water equal in weight to its own weight when operating in displacement mode.
A displacement-hull vessel always displaces a volume of water equal to its own weight, regardless of its speed. At slow speeds, it is easy for a displacement-hull boat to push the water aside, forming a bow wave. As speed increases, the bow wave becomes higher and the boat tries to climb it. But the boat is not designed to do this so there is a practical limit to its speed. Displacement vessels with longer waterlines have the capability of attaining higher speeds as long as they have adequate power. Most sailboats (except sailboards and certain other light-weight boats such as racing dinghies), tugs, freighters, and true trawlers are displacement-hull vessels. The theoretical upper limit (the hull speed) of a displacement hull can be calculated with relative precision. Hull speed in knots (nautical miles per hour) is approximately 1.34 times the square root of the waterline length in feet. Thus, a displacement-hull vessel with a waterline length of 36 feet has a maximum speed of approximately 8 knots (9.2 statute miles per hour). Despite their slow speed, displacement-hull vessels have many advantages and special uses. They are steady and comfortable and can handle rougher water than their planing hull cousins (see below). Engine-powered displacement-hull vessels are typically highly fuel efficient.
Above hull-speed a planing-hull vessel rides on its bow wave or "on-plane." When planing, it uses most of its power to move forward instead of pushing the water aside and displaces a volume of water less than its own weight. Generally, flatter hull bottoms allow boats to plane more easily. Runabouts, speedboats, sportfishing boats, and PWC are examples of planing-hull vessels. Powerdriven planing-hull vessels are generally less fuel efficient than displacement-hull vessels of comparable size and weight.
As the name implies, a semidisplacement hull has both displacement and planing characteristics. Up to a certain power and speed, a semidisplacement hull behaves as a displacement hull. Beyond that point, the hull can rise to a partial plane. Increasing the power of a semidisplacement hull vessel increases its speed. It never gets fully "on top," however, and is not as fast as a vessel with a true planing hull. Most trawlers and many cruisers fit into this category.
Multihull vessels include sailing catamarans (two hulls) and trimarans (three hulls). Although technically a displacement-hull vessel, a multihull is able to escape the restriction of hull speed because the narrow hulls create very little wave resistance and because this type of vessel typically carries a great deal of sail. These boats may be difficult to maneuver at docking speeds because they lack the momentum that heavier, ballasted boats use to maintain forward motion.
There is no single, all-purpose, perfect hull design. Boat builders strive to find a happy compromise among conflicting design objectives.
THE BASIC BOAT
Learning to sail is rather like going to a foreign country. Everyone seems to speak a different language. But don't let this trouble you, for the language will soon become familiar. Once you cast off from shore, your boat becomes a self-contained world. To function within that world you need to learn the parts of your boat and their uses. Go over them often so there is no question in your mind.
Keel -- a weighted fin that, when attached to the bottom of a sailboat, keeps the boat from slipping sideways in the water and allows it to sail upwind.
Centerboard -- A sailboat without a keel may have a centerboard. A centerboard is a wooden or metal fin housed in a centerboard trunk that serves the same purpose as a keel. It can be lowered to overcome the boat's lateral motion.
Beam -- the maximum width of the hull.
Deck -- the horizontal upper surface of the boat.
Stern -- the back of the boat.
Bow -- the front of the boat.
Aft, after -- toward the stern.
Forward -- toward the bow.
Windward -- toward the wind.
Leeward -- away from the wind.
Aloft -- overhead.
Rudder -- the fin at the stern of the boat used for steering.
Tiller -- the wooden or metal steering arm attached to the rudder. It is used as a lever to turn the rudder.
Tiller extension -- a wooden or metal pivoting extension attached to the tiller. It is usually found in dinghies and enables the skipper to steer accurately while hiking out.
Wheel -- On larger boats the wheel replaces the tiller and is used to turn the rudder.
Mast -- the vertical pole or spar that supports the sails and boom. The top of the mast is called the masthead.
Boom -- the horizontal spar which is attached to the mast to support the bottom part of the mainsail.
Hiking out -- leaning the weight of the crew over the windward side to help keep the boat on an "even keel."
Port -- the left side of the boat as you face forward.
Starboard -- the right side of the boat as you face forward.
Mainsheet -- the line used to make the major adjustments to the trim of the mainsail.
Boom vang -- an adjustable tackle or rod that prevents the boom from lifting. A rodtype boom vang also keeps the boom from dropping on deck.
Lifelines -- plastic-coated wires enclosing the deck to keep the crew from falling overboard. Lifelines are suspended from metal supports, called pulpits and stanchions.
Traveler -- a slide, running across the boat, to which the mainsheet is led. The crew can change the trim of the mainsail by adjusting the slide position.
Topsides -- the sides of the hull above the waterline.
The standing rigging is a collection of wires that supports the mast. On more sophisticated boats, the standing rigging is more complex and can be adjusted to optimize a sail's performance. The basic standing rigging consists of:
Headstay -- a wire that runs from the top of the mast (or near the masthead) to the bow and onto which the jib is attached. It supports the mast, preventing it from falling backwards.
Backstay -- a wire that runs from the top of the mast to the stern and supports the mast.
Shrouds (sidestays) -- wires that run from the masthead (or near the masthead) to the sides of the boat to support the mast and prevent it from swaying.
Sails -- are the power supply of the sailboat. They are most frequently made of Dacron, a synthetic fiber, used because of its resistance to stretching. Other materials such as nylon, Mylar, and Kevlar are also used in sailmaking. Types of sails are:
Mainsail -- the primary and most easily controlled source of sail power, attached along the front edge to the mast and along the bottom edge to the boom.
Spinnaker (chute) -- a balloonlike sail, often colored, used when running with the wind.
Jib (headsail) -- the sail set forward of the mainsail and attached to the forestay using jib hanks.
Genoa (headsail) -- a large jib with an overlap aft of the mast.
Each part of a sail has a name:
Head -- the top corner of the sail.
Tack -- the forward lower corner of a sail.
Clew -- the back lower comer of a sail.
Luff -- the leading edge (front) of a sail. The luff of the mainsail attaches to the mast, and the luff of the jib attaches to the forestay.
Foot -- the bottom edge of a sail. The foot of the mainsail attaches to the boom. The foot of the jib is unattached and consequently more difficult to control.
Leech -- the trailing (back) edge of a sail.
Battens -- support sticks held in pockets to keep the leech from flapping and to add support to the sail.
Draft -- the fullness or roundness of a sail.
The running rigging consists of ropes (called lines) that pull the sails up and adjust the sails' shape. Unlike the standing rigging, the running rigging is not stationary. When sailors speak of "trimming" sails to find the most efficient shape, they mean that the sheets are being let out (eased) or pulled in (trimmed).
The running rigging includes:
Halyards -- lines used to raise (hoist) sails and hold them up.
Mainsheet -- a line used to trim the mainsail; it is led through a series of blocks to form a block and tackle.
Jib sheets -- two lines, one on each side of the boat, to trim the jib.
The topping lift, which prevents the boom from dropping on deck, is part of the running rigging. The downhaul, outhaul, and cunningham are also running rigging. We will discuss them later.
Halyards attach to the top or head of a sail. Halyards run through the top of the mast by means of a sheave or block (pulley) and then down to the bottom of the mast. A halyard can be internal, inside the mast, or external, outside the mast. The main halyard raises the mainsail and the jib halyard raises the jib.
Halyards sometimes terminate at the base of the mast, requiring the crew to be at the mast when hoisting and lowering the sails. A better system is to have the halyard lead back to the cockpit through turning blocks and padeyes (blocks and eyes through which a line is threaded to give it a clear, safe run). The sail can then be hoisted by the crew without leaving the safety of the cockpit.
Most boats have winches on the mast or on the deck to aid in the hoisting of sails. Winches pull on lines mechanically and safely. They consist of a drum that rotates only in a clockwise direction around which the line is wrapped and a crank handle to rotate the drum. Winches are discussed in the Skills Afloat section of this part.
Sheets control the shape of the sail and sail trim or position of the sail. The mainsheet and jib sheets are quite different from one another. The main...

Présentation de l'éditeur

Written by America's foremost instructional authority, the new edition of SAILING
FUNDAMENTALS is widely recognized as the official 'learn-to-sail manual' of the American Sailing Association (ASA) - and used in the training programs of many yacht clubs, colleges, and sailing groups, including the U.S. Coast Guard Auxiliary nationwide.
While most introductory sailing books reflect the biases and idiosyncrasies of their authors, SAILING FUNDAMENTALS is extensively pretested by ASA professional instructors to ensure it offers only the fastest, easiest, most systematic ways to learn basic sailing and coastal cruising. This invaluable guide covers every aspect of beginning sailing-from hoisting sail to docking and anchoring - and specifically prepares readers to qualify for sailing certification according to international standards.

Détails de l'édition

• Éditeur: Prentice Hall & IBD
• Date d'édition: 1987
• ISBN 10: 0671605984
• ISBN 13: 9780671605988
• Reliure: Broché
• Langue: anglais
• Nombre de pages: 206
• Illustrateur: Betz Marti
• Coordonnées du fabricant: non disponible