Melbourne Dockland Sailing School - LEARN TO SAIL ON LINE
Welcome aboard to the Dockland Sailing School - Online Inroduction To Sailing Course.
The DSS follows the International Sailing Schools Association – Introduction to Sailing Course. Details of the Association can be viewed at www.sailingschools.org
The focus is to give participants the theory and knowledge that under pins all sailing. The aim is to give participants a base to start sailing as a crew in a Yacht Club environment. Many boat owners / skippers look for and need crew to go sailing, especially racing. Whilst you may get out on the water and in time learn a 'job' or two, it's very unlikely that you will get to steer and so control the yacht.
No manual can give a complete learning in the sport of sailing. What this manual does, however, is to set out in summarised form the basic concepts that you will need to know to equip you to be a competent skipper or crew on the water. You will need to read as many magazines and texts as you can as the extent of experience and innovation in the sport is boundless.
Theory alone does not create competency. Sailing and more sailing will make the theory that you learn instinctive as you sail. The combination of both is the fascination of the sport.
At first sight the theory may be off-putting, but you will find that as you embark on the water, the knowledge that you have gained in this course will give you an immediate inner confidence. You will know why things are happening. And more importantly how to control and correct them.
The aim of the on line course is to intoruduce you to many of the fundermentals and help you as a safe and competent sailor, confidently able to take your place in a wonderful sport with great traditions and years of pleasure ahead of you.
SAILING IS LEARNING!
Introduction to Sailing - Theory Sailing Course
1.0 Getting to Know the Yacht
1.2 Nautical Terms
1.3 Parts of Hull and Deck
1.4 Sailing Types
1.5 Rig Types
1.6 Mast Rake and Bend
1.7 Mast Tune Checks
1.8 Mast Tune Adjustments
1.9 Word List
1.10 Time at Sea
1.11 Bearing of an Object to the Boat
1.12 Tips on Selecting a Trailerable Yacht
2.0 Rope Work, Winches, Blocks and Tackles
2.2 Rope Characteristics
2.5 Blocks and Tackles
3.0 Basic Stability
3.2 Forward Motion
3.3 Heeling and Righting
3.4 Weather and Lee Helm
3.5 The Keel
3.7 Back to Front Steering
3.8 Pivot Point
3.9 Propeller Affect
Assessment 1- Self paced.
GETTING TO KNOW THE YACHT
1.1 Humankind has been moving across the surface of the seas since the dawn of history. Efficient sailing in a form as basically understood today has a history of some four hundred years. It is within only the last ninety years that the modern yacht has evolved.
Today's efficient sailing craft is the product of the experience of cruising and the advancement of racing design. Many advancements from racing are taken for granted as part of every day sailing.
Because of the history associated with the sport it is difficult if not impossible to overlook the many historical aspects of the sport. For these reasons there are many terms and expressions that are today still an integral part of sailing. To enjoy your sailing you will need to learn and become comfortable with some strange names and terms.
1.2 NAUTICAL TERMS
These are set out in Word Lists in paragraph 1.9.2.
1.3 PARTS OF THE HULL AND DECK
The following diagrams show:
• Rig Configurations
• Keel Configurations
1.4 SAILING TYPES
1.4.1 The major types of sailing craft are:
Dinghy This type is usually smaller and are not self righting; They have no keel and rely on crew weight for stability. They are usually launched off the beach.
Yacht A sailing craft that has a keel or centerboard and is self righting.
Auxiliary yacht A yacht with a motor, either as a detachable outboard motor or one built into the yacht.
Motor sailer A vessel primarily designed to be propelled by a motor but with the
ability to sail. Usually not efficient in sailing to windward.
Trailer sailer A yacht that complies with the road transport laws and is trailed on a road trailer without the need for special permits. This type is launched off its road trailer.
Multihull A yachts with 2 or 3 hulls.
1.4.2 The usual materials for construction are:
Wood The traditional material, which can be plank, plywood, diagonal stripped or a combination of layers. With newer epoxy and resin chemicals, wooden hulls can be made immensely strong and light.
Fiberglass Also known as Glass Reinforced Plastic (G.R.P.)
Aluminum This metal needs care to prevent electrolysis in seawater.
Steel this is popular for cruising boats and for amateur builders.
Ferrocement This is concrete layed over a wire framework. This was popular with amateur builders in the 70's and 80's.Building needs care and controlled conditions. These are not recommended to purchase, as they cannot be insured.
1.4.3 YACHT TYPES
Heavy Displacement As the name implies these hulls are of heavy weight. The
hull does not surf or easily exceed its displacement hull speed. This type is most flavoured in cruising yachts and they usually have long to medium length keels. The ballast ratio is usually in excess of 50%.
Light Displacement This refers to the relationship of the displacement weight of the boat to its ballast. A ballast ratio of 50% or less usually applies. This type is most flavoured for racing yachts. The hull form surfs easily and can exceed its displacement hull speed.
Centerboard The 'keel', in this type of boat is in the form of a plate or fin that can be raised and lowered. The boat's ballast can be either inside the hull or by attachment to the centerboard. The ballast gives the boat a self righting ability. With the centerboard raised the boat makes considerable side slip or leeway. This type of boat is most flavoured in areas of shallow water or where sand bars are a common feature.
Trailer sailers are a larger form of centreboarders.
Ballast Ratio This refers to the relationship of the weight of the boat (its displacement) to the weight of the boat's ballast. Ballast is weight added to a boat to give it stability. So a yacht with 1000 kg's of ballast and a total displacement of 2000 kg's, is said to have a ballast ratio of 50%. The lower the weight of ballast in relation to the displacement, the lower the percentage ratio.
Displacement Hull Speed This is a theoretical speed and is a function of the
boat’s waterline length. Many other design factors will affect the speed. The action of waves, sail plan and other practical matters can induce a speed greater than a yacht's displacement hull speed. Most yachts have a displacement hull speed in the range of 5 to 9 knots.
The lighter the hull displacement and ballast ratio the higher the
potential hull speed.
1.5 RIG TYPES
The mast may be either a masthead rig or a fractional rig.
In a masthead rig, the forestay attaches to the mast at the top of the mast.
In a fractional rig, the forestay attaches to the mast at a point below the top of the mast and is expressed as a percentage of the mast length. Example 3/4, 7/8 or 15/16 rig.
1.5.2 In a fractional rig the running backstay performs the task of the backstay in a masthead rigged yacht. Running backstays may be dispensed with where the spreaders are angled aft to support the mast. In a fractional rigged yacht the unsupported length of the mast above the hounds (that is the point where the forestay joins the mast) may also be supported and controlled by jumper struts and stays.
1.5.3 Where spreaders are angled aft the mast can be set with pre-bend by tension on the cap shrouds. This setting cannot be easily changed when sailing.
1.5.4 The lower shrouds are to control sideways bend in the mast. Fore and aft lowers control the amount the mast will move fore and aft when the sail controls are used.
1.5.5 The intermediate shrouds (diagonals) perform the same function as the lower shrouds but in the upper sections of the mast. These are placed between the various sets of spreaders.
1.5.6 The cap shrouds are of continuous wire from the top of the mast or the hounds in a fractional rig to the deck.
1.5.7 With modern technology, there is constant development in the design of rigs and the combination of stays, shrouds and struts.
1.5.8 "Running rigging" refers to the halyards and other lines for hoisting and adjusting the sails and mast, while sailing.
IN LINE SPREADERS
FRACTIONAL RIG ANGLED SPREADERS
NO RUNNERS REQUIRED
HEADSAIL , MAINSAIL
Head, Battens, Telltales, Luff, Leech
Main Sheet, Foot, Tack, Clew, Headsail Sheet
1.6 MAST RAKE AND BEND
1.6.1 When first setting up the mast in the yacht it is necessary to have the mast perpendicular and with no lean to either side.
The sailing performance of a yacht can be affected by raking the mast. 'Rake' is presetting of the mast fore or aft of perpendicular, and is not easily changed when sailing. Mast rake is a function of mast 'tuning'. Mast rake can be used to help correct 'weather' or 'lee' helm that is caused by design problems.
1.6.2 Also a mast raked forward is used in light winds and raked aft for heavy winds.
1.6.3 Once the rake has been set into the mast, bend can be induced into and out of the mast. Unlike rake, sail and rig trimming induce mast bend. Mast bend is a function of trimming and is carried out when sailing and is a constant function of trimming the sails. Mast bend is a method used to change the shape of the sails and affect their power.
On yachts with angled spreaders pre-bend can be set into the mast and fine mast bend adjustments can be obtained while sailing by using the backstay and runners.
1.6.4 If the mast is permitted to lean athwartships (sideways), sailing performance will be adversely affected.
This is usually obvious by the yacht sailing not as close to the wind on one tack
than on the other when the sails are set identically on the opposite tack. The yacht will sail less high, which is close to the wind, on the tack on the opposite side to which the mast is leaning. Leaning to port, the yacht sails high on port tack and low on starboard tack.
1.6.5 Stretch will occur in the standing rigging even though made of wire or rod.
Therefore regular attention should be given to check the tune of the mast and rig
RAKE MAST STRAIGHT BEND MID FORWARD-TIP AFT
1.7 MAST TUNE CHECKS
Rake - Haul a plumb bob to the masthead with the mainsail halyard. Note
how it hangs fore or aft in relationship to the aft side of the mast.
Lean Take the main halyard to the bottom of the cap shroud at the deck.
Secure the tail of the halyard. Move to the other side and the halyard
should also touch the deck at the base of the other cap shroud.
Twist Sight up the back of the mast and sideways twist will be seen.
Inversion Stand away from the boat and sighting abeam, sight a straight edge
to the mast, fore and aft out of column will be seen.
1.8 MAST TUNE ADJUSTMENTS
1.8.1 Rake Adjust forestay, backstay and lowers.
Aft rake; forestay lengthened, backstay shortened, forward lowers loosened and aft lowers tightened.
Forward rake; forestay shortened, backstay lengthened, forward lowers tightened and aft lowers loosened.
Lean Adjust cap shrouds and lowers, letting off the lean side; take up on
the other side.
Twist Take up the cap, lower or immediate opposite to the side to which
the mast twists.
Inversion Seek expert advice, as additional standing rigging may be required,
e.g. inner forestay or forward lowers or the mast base may need to be re-positioned.
LEAN, BOW, INVERT
1.9.1 Sailing has more traditional terms than perhaps any other sport. The modern sailor is dispensing with many older terms. Do not let these unfamiliar terms bog you down. They will become familiar with use.
For those who wish to study deeper, the 'Oxford Companion to Ships and the Sea', is a scholarly and entertaining book of nomenclature, history and sea battles.
The following Word Lists do not include words, which are dealt with in detail in
1.9.2 GENERAL TERMS
Abeam in a direction at right angles to the fore and aft line of the vessel
Aft behind or towards the stern.
Ahead in front of.
Amidships in the middle of the vessel.
Astern behind the vessel.
Beam the width of the vessel.
Bearing away turning away from the wind
Beating sailing towards the wind or with the sails hauled close inboard.
Bend on to tie something on, example, bend on the mainsail.
Broach to heel violently the opposite way to the wind usually under a
For'ard ( forward ) in the front section of the vessel or towards the front.
Going about or tacking or changing the wind from one side to the other.
Gybe ( jibe) to turn the stern of the vessel through the wind. The opposite to a
Chinese gybe to have the wind blow on the same side of the vessel as the mainsail boom and the top section of the mainsail will change sides before the rest of the sail; a dangerous situation.
Heave to to bring the vessel to a halt usually with the wind abeam.
Hoist to raise on a halyard.
In irons pointing head to wind without being able to tack or bear away.
In stays being in irons but moving astern.
Lee, leeward on the side opposite to the wind.
Lee-o, helm down to push the tiller to leeward as part of the manoeuvre of
tacking, the better call is 'tacking'.
Luffing, luffing up turning towards the wind without tacking.
Port the left hand side of the vessel looking for'ard, red navigational aids.
Port tack having the wind on the port side when sailing.
Reefing, reducing sails to take in the sails and reduce their area when sailing.
Round up to violently and without control, luff, usually under spinnaker.
Starboard the right hand side of the vessel when looking for'ard.
Stern the aft end or back of the boat.
Tacking turning the head of the vessel through the wind. The opposite of
Windward, weather the side closest to the wind.
1.9.3 HULL AND DECK
Athwartships placed across the vessel.
Bow the most for'ard section of the vessel.
Cleat a device for securing the end of a sheet or halyard.
Coaming a raised section around the cockpit.
Cockpit the lowered section of the deck aft in which the crew work.
Coach house the cabin top.
Companionway a vertical entrance leading below decks.
Fairlead a deck fitting through which a rope is led to change its direction.
Foredeck the portion of the deck for'ard of the mast.
Freeboard the height of the hull from the waterline to the deck line.
Gunwale pronounced 'gunnel', the edge where the deck joins the hull.
Hatch a horizontal opening in to the hull that opens outwards.
Helm the equipment used to steer the vessel usually a steering wheel or
Jackstay/Jackline a line running fore and aft for the crew to clip onto when
moving about the boat.
L.O.A. the overall length of the vessel.
L.W.L. the length of the vessel at the waterline.
Tiller the device attached to the top of the rudder and used to turn the
Tumblehome the curvature of the freeboard from the LWL to the gunwale.
Sheer, sheerline the curvature of the deck along the gunwale fore and aft.
Overhang the section of the LOA extending past the limits of the LWL fore
Pulpit the metal fitting surrounding the bow to prevent the crew falling
Pushpit same as a pulpit but around the stern.
Quarter fore or aft in relation to the vessel, the area between ahead and abeam,
for’ard quarter or abeam and astern, aft quarter.
Toerail a fitting along the gunwale for strength and protection.
Rudder the under water appendage which turns the boat.
Stem the section of the bow extending from the deck to the LWL.
Stanchion a metal post supporting the life lines.
Skeg an underwater appendage that supports and protects the rudder or
Strong point specially designed fittings placed around the deck so that crew can
attach their safety harnesses.
Transom, tuck the sloping stern section of the hull.
Stay '1 x 19' the construction of rigging wire being comprised of 19 strands.
Backstay the stay from the top of the mast or the hounds to the stern
supporting the mast.
Bail; bale a metal fitting at the base of the mast to which control lines are
Barber haulers control devices to exert athwarthship pressure on sheets.
Boom vang a device for controlling the upward pressure on the mainsail boom
caused by the mainsail.
Boom a spar to support the foot of the mainsail.
Brace a sheet used on a spinnaker through the outer end of the spinnaker
Cap shroud the stay supporting the mast from the top or hounds to the deck.
Car a moveable deck fitting through which the headsail sheets are led.
Chainplate the fitting on the deck to which the shrouds are attached.
Cunningham eye a block and tackle for exerting downward pressure on the
luff attached to a ring in a sail.
Downhaul control devices to exert downward pressure on sheets, also called
Forestay the front stay supporting the front of the mast and the headsail.
Gooseneck the fitting attaching the boom to the aft side of the mast.
Halyard rope or wire or combination of both used to hoist sails.
Hounds the fitting that attaches the stays/shrouds to the mast.
Intermediate stay supports the mast between the mast and a spreader. Also
Jockey pole a bearing out spar used with a spinnaker.
Kicker, fore guy, running rigging to exert downward pressure on the spinnaker pole.
Lowers lower stays supporting the mast from the lowest set of spreaders to
Mainsheet the sheet controlling the mainsail.
Mast boot a flexible water proof fitting at the base of the mast to seal the cabin
Mast a spar for supporting the mainsail.
Mizzen mast a mast at the stern of the vessel to support mizzen sails.
Outhaul a device for exerting pressure on the foot of the mainsail.
Preventer see kicker.
Rod rigging solid metal rod used for rigging instead of wire.
Running rigging those parts of the rigging that are moveable.
Sheet a control line attached to the clew of a sail.
Spinnaker pole a spar used to set a spinnaker.
Spinnaker ring, or bell the fitting on the for'ard face of the mast to attach the
spinnaker pole to the mast.
Spreader a fitting attached to the mast for exerting outward pressure on mast
Standing rigging those parts of the rigging that support the mast that are not
adjustable when sailing.
Traveller a track to which the mainsheet is attached to permit athwartships
movement of the mainsail.
Triatic stay a stay from the top of the main mast to the top of the mizzen mast.
Uphaul (topping lift) running rigging to lift up the spinnaker pole.
Whisker pole a light weight spar used to pole out a headsail when running before the wind. Used in boats without spinnakers.
Asymmetrical spinnaker a spinnaker with one luff, set without a pole, non
Battens devices to support the roach of the mainsail.
Bolt rope same as a luff tape except on the luff of the mainsail.
Clew the corner of the sail attaching to the sheet or the outer end of the
Foot the bottom edge of a sail.
Foot line a line in the foot of a headsail for tension.
Genoa a headsail that overlaps the mast.
Hank a device for attaching the headsail to a forestay.
Head the top corner of the sail attaching to the halyard.
Headboard a fitting to strengthen the head of a sail.
Headfoil, luff groove an extruded section placed up the forestay to hold the luff
tape of a sail.
Headsail, jib the principal sail set in the fore triangle. A jib is a non overlapping
Kite, chute, ‘naker slang for a spinnaker.
Leech the back ( aft ) edge of a sail.
Leech line a line in the leech used for tension.
Luff the for'ard edge of a sail, the edge closest to the wind.
Luff tape cloth attachment sewn into the luff of a headsail for attachment to a
Mainsail the sail set on the mast and the boom.
MPS multi purpose spinnaker. A form of asymmetrical spinnaker used in
Reefing eye a point for attaching the reefing lines to the mainsail.
Roach The curved section of the leech of the mainsail outside a line drawn
from the head to the clew.
Spinnaker a symmetrical sail set when running before the wind.
Staysail a secondary sail set in the fore triangle.
Storm jib a small heavy weight cloth sail.
Tack the corner of the sail attaching to the deck or the inner end of the
Trysail a special storm sail set in extreme weather conditions on the mast
and independent of the boom.
1.10 TIME AT SEA
1.10.1 The old romantic method was indicated by bells. Now of historical interest but still ingrained in the language. A sequence of bells was rung during the period of the watch. The watch was a set period during which a crew worked the boat. 8 bells were rung at the end of a four hour watch.
Universal Time (UT) or Zulu Time, is the time at the Prime Meridian of longitude, 00:00 at Greenwich. Formerly referred to as GMT, or Greenwich Mean Time.
24 hour time. This expresses the time in 24 hours of the clock instead of am
or pm. 35 minutes past 9 o'clock is written as 09:35 hrs.
The same time in the evening is written as 21:35 hrs.
1.11 BEARINGS OF AN OBJECT FROM A VESSEL.
1.11.1 The direction of an object can be referred to in three ways in relationship to the vessel.
1.11.2 Compass bearing. This method is not related to the ship's heading and refers to the bearing of the object related to the compass, called as; 045; the object is at that bearing of the compass from the ship N 045
1.11.3 Bearing to the ship's heading. This is expressed in degrees relative to the ship's heading and is called as;
Port or red 30; the object is 30off the port bow.
Green or starboard 170; the object is 10off the starboard side from dead
1.11.4 Clock method. This assumes that the ship is in the centre of a clock face. The bow points to 12 o'clock. It is used generally to call the bearing of objects forward of abeam;
• A at 2 o'clock, means that A is approximately 60off the starboard bow.
• B is at 9 o'clock, means that B is on the port beam.
This method is not usually used at sea but in racing and close quarter manoeuvring.
1.12 TIPS ON SELECTING A TRAILERABLE YACHT.
1.12.1 There are many styles of this class but they fall into two types, traditional
TRAILERABLE YACHTS and SPORTSBOATS.
Sportsboats are for the thrill seekers, are go fast and technical to sail. They usually have additional wings on the side for the crew to get outboard to help stability. Not for the beginner.
1.12.2 You will need a design that is easy to sail and handle, with a minimum of fuss to rig and launch and with reasonable stability. Sometimes the boat with good accommodation may not necessarily be a good sailing boat.
Rigging and launching. Remember at the end of the day if you are tired, cold etc recovering and de-rigging can be quite a chore. So look for a boat that makes this easy. Tall masts can be difficult to handle with only 2 crew.
1.12.3 Stability and resistance to leeway comes from the boat’s keel. There are two basic types, being a swing keel and a lift keel. Do not even consider a shallow draft or bilge keel as these types do not give sufficient resistance to excessive heel and leeway. Bilge keel is designed for areas where the tide dries out and the boat will sit upright on the seabed or harbour bottom.
A swing keel acts on a pivot and swings back into the hull. Therefore there can be limitations to the length (depth of keel when down).and ballast on the end of it, due to the limited space into which it can swing up into the hull. These boats tend to rely more on ballast fixed inside the boat. Swing keels are not usually very heavy.
The sailing outcome in swing keelers is that they are good in light conditions but
suffer a little with heel and leeway when it blows.
A lift keel, the keel lifts vertically into the boat and may actually protrude through
the cabin top when fully raised. This is as it is designed and is ok. This type can
give greater depth of keel when lowered (less leeway) and can have an external
ballast bulb on the end of the keel (better stability). These types of boats tend to
have taller masts because they are more stable and can carry more sail area. If
considering a lift keel make sure that the box inside the cabin through which it lifts is sealed fully to the deck head and does not open into the cabin.
Try the lifting gear to make sure it can be easily lifted MANUALLY. If an electric
lift and you have a flat battery or hydraulic pump which fails, you may have to
wade/swim ashore if the keel cannot be lifted manually.
1.12.3 Check to see that the outboard motor is easily accessible from the steering position and you don’t have to get out board of the cockpit or life lines to operate it.
1.12.4 Then it comes to sails. The most important feature when learning is to be able to reef the sails easily if the wind picks suddenly.
Of course remember that it is a sailing boat and in most cases if the wind and waves are big it will sail more efficiently than it will motor. So put into practice sail
shaping and trim. Reefing is especially an important skill.
1.12.5 There are all sorts of mainsail reefing systems. But the best is one that is wholly operated from the cockpit. No one has to go to the mast and one person can do it.
1.12.6 Remember that if the boat feels safe you are safe. Practice in quite times putting the reef in and out.
ROPE WORK / WINCHES / BLOCK AND TACKLES
Natural fibre is now rarely used on modern yachts. Man-made fibres have greater
strength and generally superior characteristics. The lines used on a yacht have
specific names and there are very few 'ropes'. They are halyards, warps, sheets,
guys, and so on. Handling the lines on the yacht is an integral part of crewing.
The more you practice the easier it becomes to lay the sheet to the winch, coil, cleat, and tie knots. This part of the text is essentially read, then do.
2.2 ROPE CHARACTERISTICS
2.2.1 There are numerous types of materials, each with their own special characteristics.
Polypropylene floats indefinitely, is somewhat elastic and is good for general use in painters and mooring lines. This is the orange plastic looking line.
Polyester is a good all-purpose rope for sheets, halyard tails (Dacron)
and working sail and deck lines.
Polyamide elastic, strong and suitable for anchor lines (Nylon) and mooring ropes. Sometimes referred to as 'silver rope'.
Exotics these include materials such as kelvar, spectra and an ever
increasing new groups. They are very strong, light weight and have the qualities of wire.
2.2.2 All synthetic ropes have one thing in common; they generate considerable heat by friction causing serious burns to flesh. A pair of good quality sailing gloves is an essential part of your sailing kit.
All lines should be washed thoroughly in fresh water on a regular basis to expel salt crystals in the fibres and should be protected from prolonged exposure to sunlight.
2.2.3 All ropes are described by reference to the diameter of the rope. Thus a '10mm', line has a diameter of 10 millimetres.
Rope comes in three forms of construction:
Laid single fibres are twisted into strands and the strands, usually three, are
twisted into the rope.
Braided is comprised of an inner core and outer sheath. Both components will be plaited.
Multiplait instead of three strands as in laid rope, Multiplait uses 8 or 16 strands to make up the one line. Both the inner and outer cores are multiplait.
24 PLAIT 12mm
The bowline is the most important to master as it is the most used on a boat. The
purpose of this knot is to place a loop in a line or sheet.
FIGURE OF 8
A stop knot in the end of the sheet
To a mooring ring,bollard or beam
2.3.2 A knot tied in a rope reduces its breaking strain.
A rough guide is as follows;
Reef knot retains 50% of its breaking strain
Bowline retains 60% of its breaking strain
Half hitch retains 65% of its breaking strain
Splice retains 90% of its breaking strain
Eye splice retains 95% of its breaking strain
2.3.3 The correct knot gives the best qualities of ease of tying, non slip under load and ease to untie.
Knots fall into three general categories;
Hitch used to secure a line to an object, another rope or to make a loop, eg.
Bend used to secure a rope to an object or two ropes together under strain, eg.
Knot properly called and used to put a stopper in the line eg. figure of eight.
2.4.2 Every modern yacht has some form of winch to assist in hauling in halyards or sheets. Synthetic sail cloths and lines will take such great strains that the old block and tackle method will give insufficient advantage. The purpose of a winch is to provide 'mechanical advantage'.
Mechanical Advantage is calculated as a ratio between the radius of the circle
described by the handle and the radius of the drum of the winch.
Example: length of handle = the radius of the circle = 300mm
Radius of the winch drum =50mm
Mechanical Advantage 6:1
MECHANICAL ADVANTAGE RADIUS VERSUS HANDLE LENGTH
H H H
R R R
H = 300mm H = 300mm H = 400mm
R = 50mm R = 60mm R = 60mm
MA = 6:1 MA = 5:1 MA = 6.6:1
Increasing the length of the winch handle may be a simple and inexpensive way of increasing the MA of the winch.
2.4.3 The winch acts by friction on the sheet being hauled in. So that the number of turns around the winch drum is critical for grip. The tail of the sheet must have pressure exerted on it to maintain the tight friction around the drum. If not the drum will turn and the rope slip.
When a large amount of sheet must be hauled in, it is usual for one crew to haul in the tail of the sheet and another to wind the winch handle. A minimum number of turns are first put on the winch until the majority of the sheet has been pulled on.
This prevents an override of the sheet, which can lock the sheet to the drum.
Additional turns are added to the winch as the load comes on and the sheet is
2.4.4 An ‘override’ is an accidental overlocking hitch on the drum which can be pulled so tight that the sheet must be cut away. This usually occurs if too many turns are put around the winch drum to start with or the direction in which the line leads onto the drum is incorrect.
Some methods to undo overrides are: -
a) Lead the tail anticlockwise around the drum and either pull it or take it to
another winch and winch it out by reversing the pull.
b) Take another sheet and attach it to the clew of the sail. Lead it back to the
cockpit; use another winch and winch on. This may relieve enough pressure on
the original sheet so that it can be either taken off the winch or the sail.
c) If the sheet must be cut then cut it at the clew of the sail thereby by saving as
much of the sheet’s length as possible.
Avoid overrides at all costs.
2.4.5 Modern winches are constructed so that the sheet is wound onto the drum in a clockwise direction that is, left to right. In some older designed yachts the winches are left and right handed for different sides of the boat. Fortunately these are now rare.
2.4.6 Winches come in a variety of sizes and types. The larger the winch size the greater the mechanical advantage.
2.4.7 The common types of winches that you can expect on a yacht are :-
Single speed the drum will turn only in one direction, producing a set mechanical
Multispeed turning the handle in a clockwise direction produces one rate of
advantage and reversing the direction of turn of the handle gives
another higher advantage.
Self tailing a sheet restraining clamp is affixed to the top of the winch and does
away with the need for the sheet to be tailed. As these types of
winches tend to be slower in operation they are used for halyards or
general sheets in cruising boats.
INITIAL HAUL ON
ONLY 1 OR 2 TURNS ON
NOTE: GRIP ON SHEET AND HANDLE
KEEP TENSION ON THE
SHEET WITH LEFT HAND
CONTROL THE SPEED OF
EASING WITH HAND
PRESSED AGAINST THE
DRUM AND SHEET
2.5 BLOCK AND TACKLES
2.5.1 Although not used for sheets and halyards they find their place on a yacht for backstay adjusters, outhauls, boom vangs, and other applications requiring
A straight pull requires effort equal to the weight pulled.
2.5.2 When a line is passed through a fixed block the change in direction does not produce a mechanical advantage but instead creates load on the block around which it turns. The greater the change in direction the greater the load that is imparted to the fitting and its fixing point.
2.5.3 When the block is free to move it has the effect of reducing the effort needed to haul on the load. The more moveable blocks in the system the less effort is required.
2.5.4 The wind acts on the sails and this produces force and this is the load on the sheet.
The area of a Genoa on a J 24 class yacht is about 18.8m². In 10 knots of wind this produces about 40 kgs of sheet load that must be hauled in by the crew. With the wind at 15 knots that load increases to 89 kgs and a winch becomes necessary. Block and tackles are not efficient for this job.
2.5.5 Double the number of moveable blocks in the system indicates the advantage to be obtained. An example is shown in the following diagram.
This is expressed more simply as; ‘the mechanical advantage is equal to the number of strings (falls) in the tackle’. That is, count the number of strings between the blocks. Four (4) strings, the mechanical advantage is 4:1. And so on.
The mechanical advantage of a system can be further increased by having its pull not direct but attached to another block and tackle system. This secondary system is called a ‘whip’. Within practical limits any number of extra whips can be added.
See the illustration on page 28. Each whip doubles the MA of the system attached to it.
These mechanics will help you in understanding the effort that is needed in
handling the sails and the rig. There is no need to become an engineer. Not all
sailors are beefy grinders. The less muscular crew will need the help of mechanical advantage, where ever it can be incorporated into a system, as well as handling technique.
A competent crew and skipper will use mechanics as a winning edge. Control lines, which are easy to handle, will be trimmed more often with less effort, resulting in conservation of crew energy and efficient trimming.
THE ESSENTIALS-GLOVES-KNIFE-SHACKLE SPANNER
BLOCKS SINGLE sheave DOUBLE sheave TRIPLE sheave
The object of this chapter is to give you a basic understanding of the dynamics of
the hull of a sailing boat. It will allay your apprehensions and explain why the yacht will right it self when heeled. It will also provide some insight as to why the yacht sails and handles in the way it does.
With this understanding you will approach your first sail with confidence built on
knowledge. It will lead into the better understanding of the effects of the sails on
The greatest fear of new sailors is the seemingly uncontrolled heeling of the boat.
This is part of sailing and understanding it will remove some of the 'white knuckle'
3.2 FORWARD MOTION
3.2.1 A box will not sail. The shape of the hull, the effect of the keel and the pressure of the wind on the sails, all combine to give the yacht forward motion.
The pressure of the wind pushes the hull sideways. The shape of the keel and the hull form gives less resistance to going forward. However the resultant real motion is a combination of the two interactions. The total resultant motion is shown by a parallelogram of forces.
The total force is towards the aft but there is an equal an opposite reaction. This
reaction is not directly ahead. The 'off centre' affect is the leeway from which all
3.2.2 This leeway or sideslip of the yacht can be partly overcome or minimised by the shape of the keel and the efficiency of the shape of the sails. Both will combine to create lift, which will give the hull a course through the water closer to a direct line ahead.
FORCE AND MOTION
TOTAL HULL FORCE
TOTAL SAIL LIFT
REACTION TO HULL FORCE + SAIL LIFT = FORWARD MOTION
3.3 HEELING AND RIGHTING
3.3.1 Heeling over in a yacht is principally caused by the force of the wind on the sails. It can also be caused by the position of the crew on the deck and by the way stores and equipment are positioned below in the hull.
A yacht sails best when it has a small angle of heel. This is because the underwater profile of the yacht will be less creating a smaller wetted surface and therefore less drag.
Excessive heeling will produce more leeway, which the keel and hull shape will not be able to counteract.
The angle of heel is controlled by the area/shape of the sails. Excessive heeling if not corrected will result in a capsize or loss of steering control.
3.3.2 Sailing dinghies are not self righting because their centre of buoyancy is lower than the centre of gravity. They rely on the weight of the crew to keep them upright by counter balancing the force of the wind on the sails.
A yacht with ballast is self righting as the centre of gravity is lower than the centre
of buoyancy and they act together to right the boat. Ballast can be internal in
centreboard yachts or external, that is in the keel, in keel yachts.
3.3.3 The centre of gravity (CG), of a boat is the point at which the whole weight of the boat is acting downwards.
The centre of buoyancy (CB) is a point at which the underwater volume of the hull is acting upwards.
A keel yacht with a centre of gravity positioned high up in the boat will be 'tender',
that is it easily heels. When the CG is positioned low down in the boat it is 'stiff',
and heels less easily.
As a yacht heels the CB will move away from the CG and re-positions itself as
more of the hull becomes immersed. The distance between the CG and the CB is
called 'the righting arm' or 'righting lever'. The longer the length of the righting
arm, the greater is the effect to pull the boat upright. The CG is pulling down and
the CB is pushing up at opposite ends of the righting arm. The more the boat heels the more it wants to right itself. Remove the heeling force of the wind and up it comes.
In a dinghy the CG is above the CB. The weight and position of the crew are
essential to create a righting arm.
In a catamaran the CG is above the combined CB. As the hull heels the righting
arm reduces and the force of CB gets less. The CG firstly moves towards the CB
reducing the righting arm. Then it moves past and away from the CB until the
distance becomes an increasing tipping arm. The hull becomes totally stable when capsized and cannot self right.
CB CB CB
RIGHTING ARM LONGER RIGHTING ARM
STABLE??? TIPPING ARM
RIGHTING ARM TIPPING ARM
3.4 WEATHER AND LEE HELM
3.4.1 'Weather' helm is the tendency of a yacht to turn towards the wind. This is a
desirable feature in a yacht. Excessive weather helm is a disadvantage to efficient sailing.
'Lee' helm is the tendency of the yacht to turn away from the wind. This is an
CE CLR CLR CE
WEATHER HELM LEE HELM
3.4.2 The 'helm' or feel of a yacht is a result of the interaction of the Centre of Effort (CE) in the sail plan, and the Centre of Lateral Resistance (CLR) or pivot point, in the hull.
3.4.3 The CE is the point in the sail plan where the combined forces of the wind on the sails are centred.
The CLR is the point on the lengthways shape of the underwater part of the hull
where the hull is most resistant to sideways (lateral), movement.
The CLR acts as a pivot point and the CE acts to try to turn the hull around that
If the CE is aft of CLR the effect is to force the bow of the yacht towards the wind;
which gives 'weather helm'. If the CE is ahead of CLR the effect is the opposite and the CE turns the bow away from the wind which is 'lee helm'. CE CLR CLR CE
3.4.4 The undesirable effects of 'helm' may be rectified by major changes to the design such as :-
(a) changing the underwater profile which changes the position of the CLR
(b) moving the mast position which changes the CE
(c) re-designing the sail plan which re-positions the CE
Pre-setting rake in the mast will also have an effect on the 'helm' by lowering the
CE thereby reducing heeling and producing more feel.
MAST FORWARD CE >
CHANGE RIG CONFIGURATION CE >
< CLR CHANGE UNDERWATER PROFILE
3.4.5 'Weather helm' may also be caused when sailing by excessive heeling. This effect can not be overcome by using the tiller. The water flow stalls on the rudder and the rudder has no effect as it is operating in air and water instead of solid water in contact with the rudder.
This rounding up in the gusts, weather helm’ can be corrected by trimming as follows: -
(a) in the gusts ease the mainsail traveller to leeward
(b) open the leeches of the sails
(c) open the slot between the headsail and mainsail
(d) reduce the area of the sails, by changing headsails or reefing the mainsail.
How to achieve (b) and (c) will be dealt with in the next Part.
3.5.1 The keel is important in assisting the yacht to sail in a forward direction. The keel has three main functions: -
1. Minimises leeway or sideslip
2. Permits the centre of gravity to be lower thus lessening heel and aiding stability
3. Promotes lift toward the wind (which is the opposite effect to leeway)due to the hydrodynamic forces on the keel.
4. Is a pivot point around which the boat turns. The narrower the keel, the move quickly the boat will turn.
3.5.2 A centreboard instead of a keel is primarily for function 1 above and to a lesser extent the other functions.
3.6.1 Excessive heel is undesirable yet some heel is necessary for the yacht to sail efficiently. The amount of heel varies from design to design but is usually in the range of 15to 20.
When the yacht heels the profile of the underwater wetted surface changes and
appears smaller. With a smaller area in contact with the water there is less drag. This is a highly desirable state of affairs when sailing to windward as less drag
permits the lift forces acting from the sail shape and keel to permit the yacht to be
pointed closer to the wind and sail faster.
3.6.2 As you will see from the next Chapter, when a yacht is running before the wind the sails act as an aerodynamic dragging force rather than as a lifting force.
The yacht's speed is partly a function of waterline length. The longer the LWL the faster the hull speed. But the effect of hydrodynamic hull drag must be considered.
Placing crew weight at the stern will increase LWL. But modern designed yachts
with broad flat sterns will produce excessive drag offsetting the longer LWL. The
positioning of the crew depends very much on the hull design and shape.
LARGE SURFACE AREA / SMALLER SURFACE AREA
3.7 BACK TO FRONT STEERING
3.7.1 One of the hardest practical matters to master is the fact that a yacht turns in the opposite direction in which the tiller is turned. With wheel steering, by use of blocks, the control wires are crossed so the boat turns in the same direction as the wheel when it is turned. Just like a car.
The yacht is steered from the stern. The stern is tracing a circle and the stern moves in the direction of the rudder. This causes the bow to be pushed in the opposite direction to the stern but still moving around the circle in the same direction as the stern.
3.7.2 The fact that the hull is turning in the water will create another effect that the steerer must correct. The helm will not centre itself, as happens in a car.
The helm must be centred BEFORE the bow reaches the required direction. This will correct the boat's tendency to keep turning due to the momentum build up in the turn.
RUDDER RUDDER POST
3.8 PIVOT POINT
3.8.1 The pivot point is the point about which the whole hull turns. It is about one third back from the bow and is the Centre of Lateral Resistance. It is for this reason that in a turn the stern traces a bigger arc than the bow. This always causes the stern to 'kick' in the direction opposite to the turn. If turning to the right the stern will kick out to the left. Always allow for this extra movement when manoeuvring close to other boats and jetties.
3.9 PROPELLOR AFFECT
3.9.1 A yacht's steering will also be affected when motoring by the effect of the propellor. Most propellors are right handed, that is they rotate in a clockwise direction when viewed from astern. When motoring forward there is a tendency for the stern to turn to the right and the bow to the left.
3.9.2 When reversing the propellor rotates in the opposite direction. The suction of the propeller pulling water over the rudder and the consequent discharge current will make it easy to steer to port (left) but difficult to steer to starboard (right).
CHANGE OF ADDRESS:
COURSE NUMBER: 01
ASSESSMENT PAPER 1
This paper should be completed promptly. It is worth a total of 10 marks. As these are only a sample of all the possible questions / information, all questions MUST be answered correctly.
Tick only 1 box in the answer.
1. Cap shrouds support:
1. the mast
3. spinnaker pole
2. Mast rake is
1. sideways movement of the mast
2. fore/aft of perpendicular
3. caused by pulling the backstay
3. Looking for'ard the port side is on
1. the right
4. The 'tack' of the headsail attaches to
1. the halyard
5. 3 moveable blocks incorporating 6 strings has a mechanical advantage of
6. A yacht's heeling is principally caused by……………………………………………
7. 'Weather helm' occurs when
1. the helm is balanced, or true /false
2. the bow tends to turn to the wind, or true/false
3. the stern tends to turn to the wind true/false
8. List 3 functions of the keel
9. Self righting is caused by
1. CG and CB pulling down, true/false
2. CG and CB pushing up, true/false
3. CG pulling down and CB pushing up in combination, true/false
10 List 3 actions that can lessen weather helm caused by round up, when sailing a keel boat.
THIS PAGE IS INTENTIONALLY BLANK for notes and any questions?