10.1 – Complete Sailing and Sailmaking Glossary

A

• Afterguy: The spinnaker sheet that goes through the jaw of the spinnaker pole. Used on big boats where separate sheet and afterguy attach to both spinnaker clews. Heavier than regular sheets due to increased pressure.
• Aft: Toward the rear of the boat
• Almanac: Navigation reference
• Anchor: Device used to secure a boat to the seabed
• Apparent wind: The wind experienced by a moving boat
• Aspect ratio: The height of a foil (sail, keel, or rudder) divided by its width. High aspect sails have long luffs and short feet.

B

• Backstay: Wire supporting the mast from the stern
• Barometer: Air pressure gauge
• Batten: Flexible strip inserted into sail to maintain shape
• Beam: Width of a boat at its widest point
• Bearing: Direction to object
• Beaufort scale: Wind force scale
• Becket: Loop of rope or eye splice
• Berth: Sleeping area or docking space
• Bias Elongation: See Warp
• Bight: Curve or bend in a rope
• Bilge: Lowest inner part of a boat’s hull
• Bi-Radial: A sail construction technique where radial panels emanate from the head and clew
• Block: Pulley used in sailing
• Boom: Spar at bottom of mainsail
• Boomvang: A block-and-tackle or hydraulic ram controlling boom angle. Lowering the boom tightens the mainsail leech
• Bow: Front of the boat
• Bowline: Essential knot used in sailing
• Bowsprit: Spar extending from bow
• Broach: Accidental turning into the wind

C

• Camber: Curve of a sail
• Capsize: To overturn
• Catamaran: Double-hulled vessel
• Centerboard: Retractable keel
• Chainplate: Metal plates securing rigging to hull
• Chafe: Wear from friction
• Chart: Marine map
• Cleat: Fitting for securing lines
• Clew: Lower aft corner of a sail. Outhaul attaches here on mainsails; sheets attach here on genoas
• Close-hauled: Sailing almost directly into the wind
• Companionway: Entrance to cabin
• Compass: Navigation instrument
• Course: Intended direction
• Cross cut: A sail construction technique where panels are parallel to each other and perpendicular to the sail’s leech
• Cruising: Recreational sailing
• Cunningham: Named after Briggs Cunningham, a control that adjusts draft position by changing sail luff tension

D

• Dead reckoning: Position estimate
• Deck: Upper surface of boat
• Depression: Low pressure area
• Deviation: Compass error
• Downwind Sails
  • Downwind Sails For Cruising
  • Downwind Sails Racing
• Draft:
  • The deepest part of the curve in a sail.
  • The distance from the water line to the bottom of a boat’s keel
• Drift: Movement caused by wind/current
• Drogue: Sea anchor

E

• E: The distance from the aft face of the mast to the outermost point on the boom where the mainsail is pulled
• Ease: To loosen a line
• Eye splice: Permanent loop in rope end
• Eyelet: Reinforced hole in sail

F

• Fairlead: Fitting guiding a line
• Fall off: Turn away from wind
• Fathom: Unit of depth (6 feet)
• Fender: Cushion protecting hull
• Fetch: Wind-water distance
• Fictitious luff: Imaginary line for sail design
• Fill Threads: See Warp
• Fix: Position determination
• Flattening Reef: A sail control that flattens the mainsail’s bottom part using a grommet on the leech about a foot above the boom. Also called “flattener”
• Foot: Bottom edge of a sail
• Foreguy: Line pulling the outboard end of the spinnaker pole down
• Forestay: Wire supporting mast from bow
• Foretriangle: Triangle formed by the forestay, forward edge of mast and foredeck
• Foredeck: Forward part of deck
• Front: Weather system boundary
• Furling: Rolling up a sail

G

• Gaff: Spar supporting sail top
• Gale: Strong wind
• Genoa: Large headsail
• Gooseneck: Boom attachment to mast
• Gore: Vertical panel in sail
• Gradient: Pressure difference
• Grommets: Metal rings in sail
• Gunwale: Upper edge of boat’s side
• Gybe: Change course with wind aft

H

• Halyard: Line for raising sails
• Hand: To furl or take in sail
• Head: Top corner of a sail
• Heading: Direction boat points or current direction
• Headstay: Forestay
• Headstay Sag: Deflection of the headstay to leeward and aft caused by wind force on the sail
• Head up: Turn toward wind
• Headsail: Any sail forward of mast
• Heel: Boat’s lateral incline
• Helm: Steering control
• Hull: Main body of boat

I

• I: Measurement of foretriangle height, with specific measuring points varying by rating rule
• Irons: In stays, head to wind
• Isobar: Equal pressure line

J

• J: Measurement of foretriangle base – distance between mast and forestay
• Jib: Forward triangular sail
• Jib Lead: Block or fairlead for jib sheet between clew and winch, affecting jib shape
• Jibing: Same as gybing
• Jury rig: Temporary repair

K

• Keel: Fixed underwater fin
• Kevlar: Sail fabric material
• Knot: Speed measurement (1 nautical mile/hour)
• Knots: Wind speed measure

L

• Laminate: Multi-layer sail material
• Laminated Sail Cloth: Multi-layer fabric with fiber and film bonded by adhesive, using film for bias stretch control and fiber for oriented direction stretch resistance
• Lanyard: Short line for securing items
• Latitude: North-south position
• Lazy Guy/Lazy Sheet: Lines used on large boats for jibing spinnaker, attached to inactive clew
• Lazyjacks: Lines supporting lowered sail
• Leach: Aft edge of sail
• Lee: Side sheltered from wind
• Lee Helm: Boat’s tendency to bear off when helm is released, common in light air or with forward-positioned mast
• Leeward: Away from wind
• Life jacket: PFD (personal flotation device)
• Lifeline: Safety wire around deck
• Lines: Ropes used on boats
• Log: Speed/distance record
• Longitude: East-west position
• LP: Luff Perpendicular – shortest distance from genoa clew to luff, used to express genoa size as percentage
• Luff: 1. Forward edge of a sail. 2. Sail flapping from heading too close to wind or insufficient trim. 3. Altering course toward wind
• Luffing: Fluttering of sail

M

• Mainsail: Principal sail
• Mainsheet: Line controlling mainsail
• Mast: Vertical spar supporting sails
• Mooring: Permanent anchoring spot
• Mylar: Sail material

N

• Nautical mile: 6,076 feet
• Navigation: Determining position/course
• Noon sight: Sun observation at midday

O

• Outhaul: Control line pulling mainsail clew to boom end
• Overboard: Off the boat
• Overlap: Sail extending past mast
• Overpowered/Underpowered: Describes when a boat has too much sail (heeling too much) or too little sail (causing slowdown)

P

• P: Measurement from boom top at gooseneck to highest point of mainsail on mast
• Painter: Bow line
• Peak: Upper corner of sail
• Pennant: Small flag
• Piloting: Coastal navigation
• Pinch: Sail too close to wind
• Plot: Mark position
• Port: Left side of boat
• Port tack: Wind from port side

Q

• Quarter: Aft section of side

R

• Rake: Mast’s inclination from vertical, measured from mast back at partners to main halyard plumb line
• Range: Navigation markers
• Reach: Sailing across wind
• Reacher: High-clewed genoa for heavy wind reaching, also called “blast reacher”
• Reef: Reduce sail area
• Rigging: Boat’s line/wire system
• Roach: Curved sail section beyond straight line from head to clew
• Rudder: Steering blade
• Running: Sailing away from wind

S

• Sail plan: Arrangement of sails
• Sailcloth: Sail material
• Schooner: Two-masted vessel
• Scrim: Reinforcement layer
• Scrim Cloth: Extremely loose-woven cloth laminated to Mylar for strong, lightweight sailcloth, distinctive for spaces between threads
• Seam: Join between sail panels
• Seam allowance: Extra material at join
• Sea state: Wave condition
• Shape: Three-dimensional form
• Sheet: Line controlling sail
• Shelf Foot: Mainsail option providing extra lower third shaping control via flat cloth connecting sail bottom to boom
• Shrouds: Side support wires
• Skeg: Rudder support
• Slack: Loose, not tight
• Sleeve: Mast attachment method
• Sloop: Single-masted vessel
• Spinnaker: Large downwind sail
• Spreaders: Horizontal mast supports
• Squaring the Pole: Tightening afterguy to pull spinnaker pole back
• Stanchion: Lifeline support
• Starboard: Right side of boat
• Stay: Support wire for mast
• Stern: Rear of boat
• Stretch: Fabric elongation
• Swage: Metal fitting on wire

T

• Tack: 1. Lower forward corner of sail. 2. Turning boat through wind. 3. Port/starboard designation based on boom position
• Tackle: Block and line system
• Tape: Reinforcement strip
• Tape-Drive®: UK Sailmakers’ patented system using high-strength Kevlar tapes along computer-mapped load lines to maintain sail shape
• Tabling: Edge reinforcement
• Telltales: Wind indicators
• Tentering: Fabric stabilization
• Thimble: Protective metal eye
• Thread: Sewing material
• Tiller: Steering lever
• Topping lift: Supports boom
• Track: 1. Rail for sail hardware 2. Course made good
• Transit: Alignment marks
• Transom: Stern cross-section
• Trim: Adjust sails
• Triradial: Panel arrangement
• True wind: Actual wind direction

U

• Under way: Boat in motion
• UV cover: Sail protection strip

V

• Vang: Control for boom
• Variation: Magnetic deviation

W

• Wake: Trail behind boat
• Warp: Length-wise threads in cloth
• Warp, Fill and Bias: Terms describing thread directions in woven cloth. Warp threads parallel longest edge, fill threads perpendicular. Bias refers to off-thread stresses
• Warp-Oriented Cloth: Sailcloth with greater warp direction strength, sometimes using only warp yarns glued to Mylar film
• Waterline: Where hull meets water
• Weave: Fabric construction
• Weather helm: Tendency to turn windward; measured in rudder angle degrees needed for straight course
• Windage: Wind resistance
• Windlass: Anchor handling machine
• Windward: Toward the wind
• Winch: Line handling drum