GLOSSARY OF NAUTICAL, MARINE RIGGING & SAILING TERMS
Wind on the wrong side of the sails.
Toward the rear of the boat, behind the boat.
At a right angle to the length of the boat.
Off the side, even with the boat.
An accidental jibe happens when the boat is steered or the wind shifts such that the stern of the boat accidentally passes through the eye of the wind. This causes that main boom to swing violently to the other side of the boat. Without proper preparation when jibing, the force of the boom's motion can be destructive, injuring the crew and damaging equipment. In strong winds and on large boats this force can dismast the boat and seriously injure crew members hit by the boom. Sometimes a preventer is used to reduce the possibility of an accidental jibe.
Formal measurement of a boat for documentation.
The "law of the sea".
Floating free with the currents and tide, not under control.
Having a shape that that is not adversely affected by wind flowing past it.
Toward the stern (rear) of the boat.
A mooring line fixed to the bow of the boat and leading aft where it is attached to the dock. This prevents the boat from moving forward in its berth. Its opposite, the forward quarter spring line, is used to keep the boat from moving aft in its berth.
The line around the earth where there is no magnetic deviation between magnetic north (as measured by a compass) and true north.
When a boat is in water too shallow for it to float in, i.e: the boat's bottom is resting on the ground.
Any fixed object that a navigator may use to find his position, such as permanent land or sea markers, buoys, radio beacons, and lighthouses.
To the leeward side (downwind).
Above the boat, in its rigging.
The outboard hulls of a trimaran.
In the center of the boat.
A bell required to be rung at certain times when at anchor during fog, according to the navigation rules.
A type of knot used to fasten an anchor to its line.
A chain attached to the anchor. The chain acts partially as a weight to keep the anchor lying next to the ground so that it can dig in better. Chain is also not damaged as much as line when lying on rocks. The weight of the chain also helps to absorb changes in the boat's position due to waves.
A white light, usually on the masthead, visible from all directions, used when anchored.
A locker used to store the anchor rode and anchor.
The line or chain attached to the anchor and secured to the boat.
Also called bow roller. A fitting with a small wheel that allows the anchor and chain to roll over when dropping or raising the anchor. Some anchor rollers also have a provision to store the anchor as well.
A watch kept when the boat is at anchor in case the anchor starts to drag.
A windlass used to assist when raising the anchor.
A heavy metal object designed such that its weight and shape will help to hold a boat in its position when lowered to the sea bottom on a rode or chain. See kedge, lightweight, mushroom, and plow anchors.
The act of using an anchor.
A place where a boat anchors, usually an established and marked area. Anemometer A device that measures wind velocity.
A mechanical barometer used to measure air pressure for warnings of changing weather.
Poisonous paint used on the bottom of the boat to prevent barnacles and other organisms from growing on the ship's bottom.
The apparent direction of the wind, which is affected by a boat's motion. The apparent wind is only the same as the true wind if the boat is stopped.
Toward the stern of a vessel, or behind the boat.
A flag hoisted half way up a flagpole. Also see close up.
Lying along the ship's width, at right angles to the vessels centerline.
Also called barometric pressure. The weight of the atmosphere, an average of 1013.2 millibars or 29.2 inches of mercury at sea level. Measuring the changes in atmospheric pressure can help predict weather.
A device used to steer a boat automatically, usually electrical, hydraulic or mechanical in nature. A similar mechanism called self steering gear may also be used on a sailing vessel.
A second method of propelling a vessel. On a sailboat this could be a engine.
To raise an anchor off the bottom.
The changing of the wind direction, opposite of veering. Clockwise in the southern hemisphere, counter-clockwise in the northern hemisphere.
A method of weaving the end of a rope to keep it from unraveling.
A stay (line or cable) used to support the mast. The backstay runs from the masthead to the stern and helps keep the mast from falling forward.
When the wind pushes on the wrong side of the sail, causing it to be pushed away from the wind. If the lines holding the sail in place are not released, the boat could become hard to control and heel excessively.
To remove water from a boat, as with a bucket or a pump.
A weight at the bottom of the boat to help keep it stable. Ballast can be place inside the hull of the boat or externally in a keel.
A region of shallow water usually made of sand or mud, usually running parallel to the shore. Bars are caused by wave and current action, and may not be shown on a chart.
A long vessel with a flat bottom used to carry freight on rivers. Barges are usually not powered, being pushed or towed by a tugboat instead.
An instrument used to keep a record of atmospheric pressure, such as on a paper drum.
An instrument used to measure atmospheric pressure, usually measured in inches of mercury or millibars. Inches of mercury are used because some barometers use the height of mercury in a sealed tube as a measuring device.
Atmospheric pressure as measured by a barometer.
Also batten the hatches. To put away all loose objects on the ship and to close all openings, such as ports and hatches, in preparation for heavy weather. Hatches used to be secured with battens.
Pockets in a sail where battens can be placed to stiffen the sail.
Also batten down. To put away all loose objects on the ship and to close all openings, such as ports and hatches, in preparation for heavy weather. Hatches used to be secured with battens.
A thin strip of hard material, such as wood or plastic.
Battens are attached to a sail to stiffen it to a more preferred shape. They are placed in pockets sewn into the sail called batten pockets.
Battens also used to be used to secure hatches.
An enclosed body of water with a wide mouth leading to the sea.
Sailing on a point of sail such that the apparent wind is coming from the beam (side) of the boat at about a 90° angle. A beam reach is usually the fastest point of sail. A beam reach is a point of sail between a broad reach and a close reach.
The widest part of a boat.
Abeam, at right angles to the length of the boat.
Sturdy wooden timbers running across the width of a boat . Used to support the deck of a wooden boat.
To fall off. A boat falls off the wind when it points its bow further from the eye of the wind. The opposite of heading up.
The direction of an object from the observer. "The lighthouse is at a bearing of 90 degrees."
To sail on a tack (direction) toward the wind.
Tacking. To sail against the wind by sailing on alternate tacks directions).
A method of measuring the severity of the force of wind, named after Admiral Beaufort who created the system. 0 is no wind, whereas 12 would be a hurricane.
A loop at the end of a line.
A material used to join two objects completely. Usually used to create a water tight or very secure joint.
To attach a sail and prepare it for use.
A type of knot used to connect a line to a spar or another line. Also the act of using such a knot.
A place for a person to sleep.
A place where the ship can be secured.
A safe and cautious distance, such as "We gave the shark a wide berth."
The center of a slack line. (i.e: where it sags). Also a small indented curve in a shoreline.
A mechanical, electrical, or manually operated pump used to remove water from the bilge.
The lowest part of the interior of the boat where water collects.
A cover used to shelter the cockpit from the sun.
The mount for the compass, usually located on the wheel's pedestal.
A pair of small telescopes, one for each eye, used to magnify distant objects.
A sturdy post mounted on the bow or stern to which anchor or mooring lines may be attached.
The end of a line. Also the end of the anchor rode attached to the boat.
A combination of one or more blocks and the associated tackle necessary to give a mechanical advantage. Useful for lifting heavy loads.
One or more wheels with grooves in them (pulleys) designed to carry a line and change the direction of its travel. A housing around the wheel allows the block to be connected to a spar, or another line. Lines used with a block are known as tackle.
A ladder used to board the vessel. Boarding ladders may be designed to be useful from either the water or a dock and are usually stowed when not in use.
A wave that breaks over the deck of the boat.
A pole with an attached hook at the end, used for either retrieving objects or fending them off.
A small vessel used to travel on the water, powered either by wind, power or oars. Also any small vessel carried on a larger ship. Also an abbreviation for; “Break Out Another Thousand”.
Also bosun, bos'n, bo's'n, and bo'sun, all of which are pronounced bosun. A crew member responsible for keeping the hull, rigging and sails in repair.
A large pillar, usually made of concrete or steel, to which a boat's mooring lines can by tied.
A line (rope) sewn into the luff of a sail. The bolt rope fits in a notch in the mast or other spar when the sail is raised.
Any system used to hold the boom down. This is useful for maintaining proper sail shape, particularly when running or on a broad reach.
A spar that is used to secure the bottom of a sail, allowing more control of the position of a sail.
A boomkin is a short spar that may project either fore or aft on a sailing vessel, depending on its function. Traditionally, it was a strong, usually wooden spar extending forward over the bow of a Western sailing ship holding a block through which a headsail's sheet passed; on some modern sailing yachts with long main booms it is a short spar extending aft from the stern anchoring a central backstay.
A chair traditionally made from a plank and rope, used to hoist workers aloft to maintain the rigging.
A locker where tools for maintaining the deck, rigging and sails are kept.
Also boatswain, bos'n, bo's'n, and bo'sun, all of which are pronounced bosun. A crew member responsible for keeping the hull, rigging and sails in repair.
A set of bearings taken from an object with a known position, such as a landmark, to determine the ship's location. A type of running fix.
The front of the boat.
A reference book named after the original author, Nathaniel Bowditch. Updated versions contain tables and other information useful for navigation.
A knot used to make a loop in a line. Easily untied, it is simple and strong. The bowline is used to tie sheets to sails.
A pole extending from the bow of a boat. The bowsprit is used to attach the headstay forward of the front of the boat's deck. This allows added sail area for the head sail.
A guy. A line used to control the movement of the object at the other end, such as a spar.
A method of making lines that allows for greater strength and durability when using modern materials.
A wave that approaches shallow water, causing the wave height to exceed the depth of the water it is in, in effect tripping it. The wave changes from a smooth surge in the water to a cresting wave with water tumbling down the front of it.
With sufficiently strong wind, large waves can form crests even in deep water, causing the wave tops to tumble forward over the waves.
A structure build to improve a harbor by sheltering it from waves.
A line attached laterally from a boat to a dock, preventing movement away from the dock.
The room from which a ship is controlled. On a smaller boat this is usually not a room, is outside, and is known as a cockpit.
A man made structure crossing a body of water, usually for the use of automobiles or train. A boat intending to pass under a bridge needs to make sure it has sufficient vertical clearance unless it is a swinging bridge or a drawbridge.
Pieces of varnished wood or polished metal on a vessel.
A term used to describe a clean and orderly ship.
An undesirable position in which a vessel is turned to expose its side to the oncoming waves.
The unplanned turning of a vessel to expose its side to the oncoming waves. In heavy seas this could cause the boat to be knocked down.
The position of an object that lies off to one side of the vessel.
Sailing with the apparent wind coming across the quarter of the ship. A broad reach is a point of sail between a beam reach and running.
An interior wall in a vessel. Sometimes bulkheads are also watertight, adding to the vessel's safety.
A type of knot used to attach a line to a shackle.
A floating device used as a navigational aid by marking channels, hazards and prohibited areas.
The vessel responsible for moving out of another vessels path according to the navigation rules. Also known as the give way vessel.
A type of flag used to identify a boater's affiliation with a yacht club or boating organization.
A point of sail similar to running where the wind is coming over the quarter of the sailboat on the same side that the main sail and boom are on. This point of sail is considered dangerous because of the possibility of an accidental jibe.
A room inside a boat.
A mechanical cleat used to hold a line automatically. It uses two spring loaded cams that come together to clamp their teeth on the line, which is place between them. Also see jam cleat.
The curvature of an object such as a sail, keel or deck. Usually used when referring to an objects aerodynamic or hydrodynamic properties.
A cylindrical buoy painted green and having an odd number used in the United States as a navigational aid. At night they may have a green light. Green buoys should be kept on the left side when returning from a larger body of water to a smaller one. Nun buoys mark the other side of the channel. Also see green and red daymarks
A manmade waterway used to connect bodies of water that do not connect naturally. Canals use locks to raise and lower boats when connecting bodies of water that have different water levels. The Panama and Suez canals are two of the most famous.
A pointed stern, such as those on a canoe.
Tightly woven cloth used for sails, covers, dodgers and biminis. Typically made from cotton, hemp or linen. Modern sails are made out of synthetic materials generally known as sailcloth.
When a boat falls over in the water so that is no longer right side up.
A rotating drum used to haul heavy lines and chains. Similar to a winch, but mounted vertically.
The person who is in charge of a vessel and legally responsible for it and its occupants.
A sliding fitting that attaches to a track allowing for the adjustment of blocks or other devices attached to the car.
A synthetic material consisting of fibers glued together with epoxy that is very strong for its weight.
The points of North, South, East and West as marked on a compass rose.
Structural pieces running fore and aft between the beams.
A knot used to tie two lines together.
To detach mooring lines as when leaving a dock.
A twin hulled boat. Catamaran sailboats are known for their ability to plane and are faster than single hulled boats (monohull) in some conditions.
A sailboat rigged with one mast and one sail.
The sag in a line strung between two points.
Material used to seal the seams in a wooden vessel, making it watertight.
A type of drag on a propeller caused by air bubbles forming near the tips of a propeller that is spinning too fast. This causes inefficiencies and unnecessary wear and tear on the propeller.
A method of using the stars, sun and moon to determine one's position. Position is determined by measuring the apparent altitude of one of these objects above the horizon using a sextant and recording the times of these sightings with an accurate clock. That information is then used with tables in the Nautical Almanac to determine one's position.
An imaginary sphere surrounding the globe that contains the sun, moon, stars and planets.
The imaginary line running from bow to stern along the middle of the boat.
A device similar to a keel, except that it is usually either removable or can pivot. Also see daggerboard. The centerboard is used like a keel to reduce the unwanted sideways motion of a boat.
A legal paper or license of a boat or its captain.
Wear caused by the friction of parts moving past each other.
Tape, cloth or other materials placed on one or more parts that rub together. By using chafing gear, hopefully the chafing gear will wear rather than the parts that it is protecting.
Storage for the anchor chain.
Metal links that are locked together to make a strong and flexible line. Chains are typically used for anchors and other places where high loads may be exerted on the line, particularly in large vessels.
Plates on the deck to which lines and stays are attached.
A store that sells nautical gear.
A buoy or other mark used to mark a navigable path through a waterway.
A navigable route on a waterway, usually marked by buoys. Channels are similar to roads where the water is known to be deep enough for ships or boats to sail without running aground.
The water level used to record data on a chart. Usually the average low tide water level.
A table designated as the area in the boat where the navigator will study charts and plot courses.
Maps for boaters are known as charts. Charts are usually issued by government agencies and include information on channels, navigational aids, water depth and hazards.
A block with one end permanently attached to a surface.
The location where the deck joins the hull of the boat.
A fitting that a line can pass through and be controlled.
When a line is pulled as tight as is can go, as when two blocks are pulled together.
Small, steep disorderly waves.
An accurate clock that is used for navigation.
Groups of boats organized for racing. Boats compete against others in the same class, assuming that their performance will be similar.
A figure eight pattern used to tie a line to a cleat.
A fitting to which lines can be easily attached.
A metal pin used to attach fittings to each other or their mounts.
The lower aft corner of a sail.
Sailing with the sails hauled tight, sailing the boat towards the wind as much as possible.
Sailing with the wind coming from the direction forward of the beam of the boat. A close reach is the point of sail between a beam reach and close hauled.
A flag hoisted to the top of a flagpole. Also see at the dip.
A boat that is able to sail well into the wind.
A type of knot typically used when mooring. It is easily adjustable, but it may work loose.
A jib or staysail that utilizes a small boom.
A boom on a jib or staysail.
Compressed natural gas. A type of compressed gas used as fuel for stoves and heaters. CNG is stored in metal cylinders prior to use. CNG is considered safer than other types of fuel such as propane (LPG) because it is lighter than air and may rise into the sky in the event of a leak. Caution should still be used as CNG can collect near the cabin ceiling, potentially causing an explosion. Propane is available in more areas around the world than CNG so CNG is not often used outside of North America.
A small wall to prevent water from entering the cockpit.
Books covering information about coastal navigation, including navigational aids, courses, distances, anchorages and harbors.
The region of land near the water.
Navigating near the coast, allowing one to find one's position by use of landmarks and other references.
A valve used to regulate the flow of water or gas.
Sole (floor) of the cockpit.
The location from which the boat is steered, usually in the middle or the rear of the boat.
Any method of passing messages, such as visual or electronic Morse code, code flag pennants and semaphore.
Used in meteorology to describe a mass of cold air moving toward a mass of warm air. Strong winds and rain typically accompany a cold front.
A method of bending a material into an appropriate shape without heating or steaming to soften the material first.
A watertight forward bulkhead designed to keep the boat from sinking in the event of a collision.
The national flag and or other flags.
A term for the international rules designed to prevent collisions between boats.
To tack. To change a boat's direction, bringing the bow through the eye of the wind.
The entryway into the cabin from the deck.
A card labeling the 360° of the circle and the named directions such as north, south, east and west.
The course as read on a compass. The compass course has added the magnetic deviation and the magnetic variation to the true course.
Magnetic deviation. The difference between the reading of a compass and the actual magnetic course or bearing due to errors in the compass reading. These errors can be caused by metals, magnetic fields and electrical fields near the compass. Prior to using a compass, magnetic deviation should be recorded for many different points on the compass as the error can be different at different points. The act of checking for magnetic deviation is called swinging.
A circle on a chart indicating the direction of geographic north and sometimes also magnetic north. Charts usually have more that one compass rose. In that case the compass rose nearest to the object being plotted should be used as the geographic directions and magnetic variations may change slightly in different places on the chart.
An instrument that uses the earth's magnetic field to point to the direction of the magnetic north pole.
A device used to draw circles.
An object made with more than one type of material.
CNG for short. A type of compressed gas used as fuel for stoves and heaters. CNG is stored in metal cylinders prior to use. CNG is considered safer than other types of fuel such as propane (LPG) because it is lighter than air and may rise into the sky in the event of a leak. Caution should still be used as CNG can collect near the cabin ceiling, potentially causing an explosion. Propane is available in more areas around the world than CNG so CNG is not often used outside of North America.
A large land mass, such as Africa, Antarctica, Asia, Australia, Europe, North America, and South America.
A region of relatively shallow water surrounding each of the continents.
A time standard that is not affected by time zones or seasons. Time measured in coordinated universal time labeled with the term Zulu. It is used so that people around the world can communicate about time without regard to individual time zones.
Any rope or line.
A small metal pin used to keep other parts from changing their position, such as to keep a nut from turning or a clevis pin from falling out.
The part of the stern aft of where it leaves the waterline.
The direction the boat is traveling or intends to travel.
A path which racing boats are to follow.
A smaller version of the flag of the country being visited. It is flown from the starboard spreader.
A small sheltered recessed area in the shoreline.
Scoop like devices used to direct air into a boat.
Also called a plow anchor. Short for coastal quick release anchor. An anchor that is designed to bury itself into the ground by use of its plow shape.
A frame to support a vessel when out of water.
The top of a wave.
The act of reaching the top of a wave.
One or more people that aid in the operation of a boat.
A fitting in a sail that allows a line to fasten to it.
When two vessels approach each other and their paths are crossing. The boat with the other boat on its starboard side is the give way vessel and must yield.
Spreaders. Small spars extending toward the sides from one or more places along the mast. The shrouds cross the end of the spreaders, enabling the shrouds to better support the mast.
Books that describe features of particular sailing areas, such as hazards, anchorages, etc.
A line used to control the tension along a sail's luff in order to maintain proper sail shape.
The movement of water, due to tides, river movement and circular currents caused by the motion of the earth.
A sailboat with one mast and rigged a mainsail and two headsails. Also see sloop.
The front edge of the boat.
A synthetic polyester material.
Similar to a centerboard, except that it is raised vertically. Like a keel, daggerboards are used to prevent a sailboat being pushed sideways by the wind.
A brand of lightweight anchor. It has pivoting flukes that dig into the ground as tension is placed on the anchor. It does not have a stock.
A device that projects beyond the side of the boat to raise objects from the water. Typically a single davit is used on the bow of a vessel to raise an anchor, and a pair are used on the side or stern of the vessel to raise a dinghy.
A navigational aid visible during the day. In the United States and Canada, square red daybeacons should be kept on the right and triangular green daybeacons should be kept on the left when returning from a larger to smaller body of water. Also see can and nun buoys.
A small boat intended to be used only for short sails or racing.
Black diamond, ball, and cone shapes hoisted on vessels during the day to indicate restricted movement ability or type. For example three balls means aground.
A position directly in front of the vessel.
A position directly behind the vessel.
Running with the wind directly behind the boat.
A method of determining position by making an educated guess based on last known position, speed and currents.
Fixed ports that do not open, placed in the deck or cabin to admit light.
The measurement of the angle between the bottom of a boat and its widest beam. A vessel with a 0º deadrise has a flat bottom, high numbers indicate deep V shaped hulls.
A mast that is stepped (placed) on the deck of a boat rather than through the boat and keel stepped. The mast of a deck stepped boat is usually easier to raise and lower and are usually intended for lighter conditions than keel stepped boats.
The surface on the top of the boat that people can stand on.
The underside of the deck, viewed from below (the ceiling.)
An instrument that uses sound waves to measure the distance to the bottom.
See magnetic deviation or compass error.
A small boat used to travel from a boat to shore, carrying people or supplies. Also known as a dink or tender.
The loss of a mast on a boat. Generally this also means the loss of some or all of the ability of the boat to sail.
A type of hull that only floats, even when in motion, as opposed to a type of hull that allows a boat to skim across the surface of the water. See planing hull.
Also hull speed. The theoretical speed that a boat can travel without planing, based on the shape of its hull. This speed is 1.34 times the length of a boat at its waterline. Since most monohull sailboats cannot exceed their hull speed, longer boats are faster.
The weight of a boat measured as a the weight of the amount of water it displaces. A boat displaces an amount of water equal to the weight of the boat, so the boat's displacement and weight are identical.
The distance traveled after correction for current, leeway and other errors that may not have been included in the original distance measurement.
Any signal that is used to indicate that a vessel is in distress. Flares, smoke, audible alarms, electronic beacons and others are all types of distress signals.
A small bag.
A red flag with a white stripe.
The alpha flag is the legal requirement for boats with divers in the water. Boats should probably display both flags when they have divers in the water.
A navigational tool used to measure distances on a chart.
A platform where vessels can make fast. The act of securing a boat in such a place. Docks are often subdivided into smaller areas for docking known as slips.
The act of entering a dock.
Licenses or registration papers for a vessel. Types of documentation vary depending on the country, vessel size and purposes.
A cover attached to the top of the cabin at the front of the cockpit. Dodgers help shelter the cockpit from wind and water.
A playful sea mammal. Also a type of fish. Also a group of piles used for mooring or as a channel marker.
A type of vent designed to let air into a cabin and keep water out by the use of baffles.
A line consisting of a braided inner core and a braided outer sheath.
A boat with a pointed stern. Known as a double-ender because the stern may look very similar to the bow.
To drop a sail quickly.
To extinguish a candle, lamp, or fire.
To steer a sailboat toward the wind.
A line used to pull down on a spar or sail.
In the direction the wind is blowing.
The depth of a boat, measured from the deepest point to the waterline. The water must be at least this depth or the boat will run aground.
A term describing the amount of curvature designed into a sail.
The resistance to movement.
Description of an anchor that is not securely fastened to the bottom and moves.
Draft. The depth of water that a boat requires to stay off the bottom. A vessel "draws" a certain amount of water.
A bridge that can be raised vertically to allow boats to pass underneath.
The velocity of a current.
Any object used to increase the drag of a boat. Typically shaped like a parachute or cone opened underwater, drogues slow a boat's motion in heavy weather. Also see sea anchor.
A dock where a boat can be worked on out of the water. The boat is usually sailed into a dry dock and then the water is pumped out.
Used to describe the decay of wood. A misnomer, dry rot is actually caused by moist conditions in fresh water.
Storing on land. Many small boats are placed in dry storage over the winter.
Tubes used to move air, such as to ventilate an enclosed area.
Design waterline. Also length waterline or load waterline (LWL). This is the length of the boat where it meets the water when loaded to its designed capacity.
To loosen the lines that control the sails.
To slowly loosen a line while maintaining control, such as when loosening the sails.
A wind coming from the east.
One of the 4 cardinal compass points. East is at 90° on a compass card.
The falling tide when the water moves out to the sea and the water level lowers.
An electrical fish finder or depth sounder that uses sound echoes to locate the depth of objects in water. It does so by timing the sound pulses.
Water or air currents flowing in circular patterns.
The use of echo sounders, radio, and various electronic satellite and land based position finders to determine a boat's location.
A tiller that is designed to be used in the event that wheel steering fails.
The national flag of a boat's home nation.
Emergency Position Indicating Radio Beacon. An emergency device that uses a radio signal to alert satellites or passing airplanes to a vessel's position.
An imaginary line around the center of the world at 0° of latitude.
A position based on dead reckoning estimations of a boat's position using estimated speed, currents, and the last known position (fix) of the boat.
The direction that the wind is blowing from.
A splice causing a loop in the end of a line, by braiding the end into itself or similar methods. It may or may not be reinforced by a metal fitting known as a thimble.
In good condition.
A fitting designed to control the direction of a line with minimal friction.
Also bear away or bear off. A boat falls off the wind when it points its bow further from the eye of the wind. The opposite of heading up.
An item such as a nail, screw, rivet or other device used to fasten objects together.
A nautical measurement equaling 6 feet (182 cm). Usually used to measure depth.
A brand name for a depth measuring device.
Federal Communications Commission Rules governing radio equipment and operation in the United States.
A propeller that can have the pitch of its blade changed to reduce drag when not in use. Also see folding and variable pitch propellers.
More than one foot. A foot is a unit of measurement used primarily in the United States. 1 foot equals 30.48 centimeters.
To push a boat away from another boat or dock by hand.
A cushion hung from the sides of a boat to protect it from rubbing against a dock or another boat.
The distance that wind and seas (waves) can travel toward land without being blocked. In areas without obstructions the wind and seas can build to great strength, but in areas such as sheltered coves and harbors the wind and seas can be quite calm. Fetch is also used to describe the act of sailing to a location accurately and without having to tack.
A construction method using layers of woven glass mats that are bonded together with an epoxy (glue).
A tool used in splicing and working with rope.
A small rail on tables and counters used to keep objects from sliding off when heeled or in heavy seas.
A block with two sets of sheaves (sometimes three), one above the other.
A type of knot that can be used to stop a line from passing through a block or other fitting.
A keel that is narrow and deeper than a full keel.
A small pier that projects from a larger pier.
Kedge anchor. A traditionally shaped anchor having flukes perpendicular to the stock of the anchor and connected by a shank. These are less common than modern anchors such as the plow and lightweight anchors.
An accurate position of the vessel, as determined by any reasonably accurate method, such as by taking visual bearings.
To fold a sail in preparation for storage.
A device used to prevent or stop unwanted flames.
A device which burns to produce a bright light, sometimes colored, and usually used to indicate an emergency.
Used to describe a light that blinks on and off in regular patterns.
To coil a line flat on the deck in spirals.
An iron bar mounted on or near the compass to correct for magnetic deviation in steal hulled ships.
The incoming tide where the water comes in from the sea, lowering the water level.
Debris floating on the water surface.
The broad flat parts of an anchor that are designed to grab and hold in the bottom.
Also a fin on a whale.
A deck that is not obstructed by a cabin.
A high position from which to steer a boat.
A propeller having blades that fold up when not in use to reduce drag. Also see feathering and variable pitch propellers.
A sea with waves approaching from the stern of the boat.
The bottom edge of a sail.
sailing slightly more away from the wind than close hauled to increase the boat speed.
A unit of measurement used primarily in the United States. 1 foot equals 30.48 centimeters. Units of more than 1 foot are known as feet.
The more common position of the sail with its length running along the ship's length as opposed to a sail such as a square sail which is mounted across the width of the vessel.
Running along the length of the boat.
Toward the bow (front) of the vessel.
The cabin towards the front of the vessel.
A weather prediction.
Also fo'c'sle or fo'csle. Pronounced fo'csle. The most forward below decks area of a vessel.
The forward part of the deck.
The forward mast of a two or more masted vessel.
The furthermost forward storage area of a vessel.
A sail placed forward of the mast, such as a jib.
A line running from the bow of the boat to the upper part of the mast designed to pull the mast forward. A forestay that attaches slightly below the top of the mast can be used to help control the bend of the mast. The most forward stay on the boat is also called the headstay.
A sail attached to the forestay as opposed to a jib which is attached to the headstay.
The space between the mast, the deck, and the headstay.
A mooring line running forward from the stern of the boat. The forward quarter spring line prevents the boat from moving backward while moored. The after bow spring line does the opposite.
Toward the bow (front) of the boat.
When a line ends up somewhere it does not belong and becomes jammed. Lines can foul on blocks, winches and other objects on a boat.
Used to describe a boat that is having difficulty remaining afloat. "The boat foundered and then sank."
A type of rig where the jib attaches below the top of the mast.
The distance between the top of the hull and the waterline.
An opening in the rail (bulwarks) along the deck to allow water to drain.
A mast made out of exotic materials so that it can support itself without the use of stays. See fully stayed mast.
Used in meteorology to describe bounderies between hot and cold air masses. This is typically where bad weather is found.
Sailing as close to the wind as possible with full sails.
A keel that runs the length of the boat. Full keels have a shallower draft than fin keels.
A sail having battens that run the full horizontal length of the sail.
A mast supported by the use of lines known as stays and shrouds.
To lower a sail. Sails are sometimes partially furled to reduce the amount of sail area in use without completely lowering the sail. This is usually known as reefing.
A type of traditional working boat using four sided gaff sails that are hoisted on gaffs.
A four sided sail used instead of a triangular main sail. Used on gaff rigged boats.
A spar that holds the top of a four sided gaff sail.
A pole with a hook at the end used to get a fish on board.
Wind speeds strong enough to qualify the storm as a gale.
A storm with a wind speed between 34 to 40 knots.
The kitchen area on a boat.
A frame used to support the boom.
Ties used to tie up the sails when they are furled.
A large sail that is a cross between a spinnaker and a genoa. Hoisted without a pole, the tack is attached at the bottom of the headstay.
A large jib that overlaps the mast. Also known as a jenny.
The direction toward the top point of the line about which the earth rotates (between Canada and Russia in the Arctic Ocean.) See also magnetic north.
The position of a boat on a chart.
Hinges for objects such as lamps, compasses and stoves so that they can remain upright as the boat rolls.
The vessel that must yield to another vessel according to the navigation rules. Also known as the burdened vessel.
GPS for short. A system of satellites that allows one's position to be calculated with great accuracy by the use of an electronic receiver.
A map of the earth drawn on a sphere so that both its distances and angles are accurate.
Time measured in Greenwich Mean Time. Coordinated universal time is a newer standard. A time standard that is not affected by time zones or seasons.
To tack.
Global Positioning System. A system of satellites that allows one's position to be calculated with great accuracy by the use of an electronic receiver.
See hand rail.
A bad knot that was probably tied in error, will not necessarily hold fast, and may be difficult to untie.
A course that is the shortest distance between two points, following a great circle. Great circle routes usually do not look like the shortest route when drawn on a flat map due to deviations caused by trying to draw a flat map of a round object such as the earth.
Any circle drawn around the earth such that the center of the circle is at the center of the earth. The shortest distance between any two points on the earth lies along a great circle.
A can buoy. A cylindrical buoy painted green and having an odd number used in the United States as a navigational aid. At night they may have a green light. Green buoys should be kept on the left side when returning from a larger body of water to a smaller one. Nun buoys mark the other side of the channel. Also see green and red daymarks.
A navigational aid used in the United States and Canada to mark a channel. Green triangular daymarks should be kept on the left when returning from a larger to smaller body of water. Red daymarks mark the other side of the channel. Also see can and nun buoys.
A solid mass of water coming aboard instead of just spray.
GMT for short. Coordinated universal time is a newer standard. A time standard that is not affected by time zones or seasons.
A ring or eyelet normally used to attach a line, such as on a sail.
Swells that become shorter and steeper as they approach the shore due to shallow water.
The anchor and its rode or chain and any other gear used to make the boat fast.
The hole in which the pin from a stern mounted rudder fits. The pin is known as a pintle.
Cruising in shallow water and spending the nights in coves.
Pronounced gunnel. The rail around the edge of a boat. Smaller versions are called toe rails.
Also called a brace. A line used to control the movement of the object at the other end, such as a spar.
Usually spelled jibe. To change direction when sailing in a manner such that the stern of the boat passes through the eye of the wind and the boom changes sides. Prior to jibing, the boom will be very far to the side of the boat. Careful control of the boom and mainsail is required when jibing in order to prevent a violent motion of the boom when it switches sides. Jibing without controlling the boom properly is known as an accidental jibe. Tacking is preferred to jibing because the boom is not subject to such violent changes. Jibing is usually needed when running with the wind and tacking is used when close hauled.
A windlass or capstan drum.
A large circular ocean current.
To attempt to contact another boat or shore, either by voice or radio.
A simple knot usually used with another knot or half hitch.
A line used to hoist a sail or spar. The tightness of the halyard can affect sail shape.
A small portable compass.
A weight attached to a line used to determine depth by lowering it into the water.
A hand hold. Usually along the cabin top or ladder.
Someone who helps with the work on a boat.
To do something carefully and in the proper manner, such as when stowing a line.
A movable block and tackle.
A locker big enough to hang clothes.
Clips used to fasten a sail to a stay.
Using such slips to attach a sail to a stay.
An anchorage protected from storms either naturally or by man-made barriers.
The individual who is in charge of a harbor.
To move all the way in one direction, such as when turning the wheel.
A command to steer the boat downwind.
A hull shape with flat panels that join at sharp angles.
A sliding or hinged opening in the deck, providing people with access to the cabin or space below.
Remove a boat from the water.
Pulling on a line.
The part on the object which is hauled upon.
A hole in the hull for mooring lines to run through.
Pipes to guide lines through the hawse hole. On large vessels anchors are stored with their shanks in the hawsepipes.
A rope that is very large in diameter, usually used when docking large vessels.
An object that might not allow safe operation. A group of rocks just under the water or a submerged wreck could be a navigational hazard.
Waves coming from the front of the vessel.
A position with the boat's bow in the direction that the wind is coming from. This will probably stop the boat and place it in irons.
To turn the bow more directly into the eye of the wind. The opposite of falling off.
The front of a vessel.
The upper corner or edge of a sail.
The top or front of a part.
The toilet and toilet room in a vessel.
The actual course of the vessel at any given time.
Any sail forward of the mast, such as a jib.
The furthest forward of all the stays on the boat.
The forward motion of a vessel through the water.
To throw or pull strongly on a line.
A light line used to be thrown ashore from which a larger rope can then be pulled.
Arranging the sails in such a manner as to slow or stop the forward motion of the boat, such as when in heavy seas.
When the water has large or breaking waves in stormy conditions.
Stormy conditions, including rough, high seas and strong winds. Probably uncomfortable or dangerous.
When a boat tilts away from the wind, caused by wind blowing on the sails and pulling the top of the mast over. Some heel is normal when under sail.
The error in a compass reading caused by the heel of a boat.
A warning from the helmsman that the boat is about to tack.
The wheel or tiller of a boat.
The person who is steering the boat.
Half of a sphere. On the globe hemispheres are used to describe the halves of the earth north or south of the equator.
The point of a tide when the water is the highest. The opposite of low tide.
A location of higher barometric pressure than the surrounding area of a weather system.
An extension to the tiller allowing the helmsman to steer while hiking. This may be desired for improved visibility or stability.
Moving the crew's weight to or past the windward rail to counteract the heeling of a boat. Typically seen when boats are racing.
A knot used to attach a line to a cleat or other object.
To raise a sail.
To raise anything up.
The type of bottom that the anchor is set in. "Good holding ground."
A storage tank where sewage is stored until it can be removed to a treatment facility.
Using a radio direction finder to steer toward a source of radio signals.
Where the water and sky or ground and sky appear to intersect.
The angle measured between two fixed objects (usually on shore) to aid in finding a boats position by determining the arc of a circle on which the boat must lie.
A floatation device shaped like a U and thrown to people in the water in emergencies.
Also displacement speed. The theoretical speed that a boat can travel without planing, based on the shape of its hull. This speed is about 1.34 times the square root of the length of a boat at its waterline. Since most monohull sailboats cannot exceed their hull speed, longer boats are faster.
The main structural body of the boat, not including the deck, keel, mast, or cabin. The part that keeps the water out of the boat.
A strong tropical revolving storm of force 12 or higher in the northern hemisphere. Hurricanes revolve in a clockwise direction. In the southern hemisphere these storms revolve counterclockwise and are known as typhoons.
A shape designed to move efficiently through the water.
A boat that has foils under its hull onto which it rises to plane across the water surface at high speed. See displacement and planing hulls.
The study of the earth's waters.
Short for Intercoastal Waterway. A system of rivers and canals along the Atlantic and Gulf Coasts of the United States allowing boats to travel along them without having to go offshore.
A sailboat with its bow pointed directly into the wind, preventing the sails from filling properly so that the boat can move. It can be very difficult to get a boat that is in irons back under sail. An old square rigger could take hours to get underway again.
A motorboat with an inboard engine.
Toward the center of the boat.
An engine that is mounted inside the boat.
A unit of measurement used primarily in the United States equal to 2.54 centimeters.
A unit used when measuring the pressure of the atmosphere. 33.86 millibars. Inches of mercury are used because some barometers use the height of mercury in a sealed tube as a measuring device.
A dinghy or raft that can be inflated for use or deflated for easy stowage.
Rules for the operation of vessels in harbors, rivers and lakes.
Away from large bodies of water, surrounded by land. See offshore.
A bay or cove along a river, sea or lake coast line. A stream or bay leading inland. A narrow passage between to bodies of land.
A system of rivers and canals along the Atlantic and Gulf Coasts of the United States allowing boats to travel along them without having to go offshore.
A set of radio, sound, and visual signals designed to aid in communications between vessels without language problems. It can be used with Morse Code, with signal pennants, and by spoken code letters.
In irons. A sailboat with its bow pointed directly into the wind, preventing the sails from filling properly so that the boat can move. It can be very difficult to get a boat that is in irons back under sail. An old square rigger could take hours to get underway again.
Lines drawn on a weather map indicating regions of equal pressure. When the lines are close together, this indicates a rapid change in air pressure, accompanied by strong winds.
A line connecting points of equal magnetic variation on a map.
A strong line, usually of flat webbing, or a wire stay running fore and aft along the sides of a boat to which a safety harness can be attached.
A rope ladder.
A cleat designed to hold a line in place without slipping. It consists of two narrowing jaws with teeth in which the line is placed. Also see cam cleat.
A fitting holding a boom or gaff to the mast.
A genoa jib. A large jib that overlaps the mast.
A man made structure projecting from the shore. May protect a harbor entrance or aid in preventing beach erosion.
A rope net to catch the jib when it is lowered.
A sheet (line) used to control the position of the jib. The jib has two sheets, and at any time one is the working sheet and the other is the lazy sheet.
The stay that the jib is hoisted on. Usually the headstay.
A small jib set high on the headstay of a double headsail rig.
A triangular sail attached to the headstay. A jib that extends aft of the mast is known as a genoa.
Also spelled gybe. To change direction when sailing in a manner such that the stern of the boat passes through the eye of the wind and the boom changes sides. Prior to jibing the boom will be very far to the side of the boat. Careful control of the boom and mainsail is required when jibing in order to prevent a violent motion of the boom when it switches sides. Jibing without controlling the boom properly is known as an accidental jibe. tacking is preferred to jibing because the boom is not subject to such violent changes. Jibing is usually needed when running with the wind and tacking is used when close hauled.
A method of lowering the sail in sections so that it can be reefed quickly.
A small sail on the mizzen mast of a yawl or a ketch.
Also known as a preferred channel buoy. A red and green horizontally striped buoy used in the United States to mark the separation of a channel into two channels. The preferred channel is indicated by the color of the uppermost stripe. Red on top indicates that the preferred channel is to the right as you return, green indicates the left. Also see can and nun buoys.
A temporary repair using improvised materials and parts.
To kedge off. A method of pulling a boat out of shallow water when it has run aground. A dinghy is used to set an anchor, then the boat is pulled toward the anchor. Those steps are repeated until the boat is in deep enough water to float.
A traditionally shaped anchor having flukes perpendicular to the stock of the anchor and connected by a shank. These are less common than modern anchors such as the plow and lightweight anchors.
A mast that is stepped (placed) on the keel at the bottom of the boat rather than on the deck. Keel stepped masts are considered sturdier than deck stepped masts.
A flat surface built into the bottom of the boat to prevent the reduce the leeway caused by the wind pushing against the side of the boat. A keel also usually has some ballast to help keep the boat upright and prevent it from heeling too much. There are several types of keels, such as fin keels and full keels.
A beam attached to the top of the floors to add strength to the keel on a wooden boat.
A sailboat with two masts. The shorter mizzen mast is aft of the main mast, but forward of the rudder post. A similar vessel, the yawl, has the mizzen mast aft of the rudder post.
The center plank on a wooden deck.
The top spoke on a wheel when the rudder is centered.
Supporting braces used for strength when two parts are joined.
A boat that has rolled so that she is lying on her side or even rolled completely over. A boat with appropriate ballast should right herself after being knocked down. A speed of one nautical mile per hour.
A method of attaching a rope or line to itself, another line or a fitting.
Heavy rolling or pitching while underway.
A line used to attach a sail to a spar.
A boat in a dry dock.
A wind moving from the land to the water due to temperature changes in the evening.
Surrounded by land.
A distinctive reference point that can be used for navigation.
A line attached to a tool.
To tie something with a line.
The ability of a boat to keep from being moved sideways by the wind. Keels, daggerboards, centerboards, and leeboards are all used to improve a boat's lateral resistance.
Imaginary lines drawn around the world and used to measure distance north and south of the equator. 90° north is the North Pole and 90° south is the South Pole, and the equator is at 0°. Also see longitude.
To put a boat in the water.
A small boat used to ferry people to and from a larger vessel.
An imaginary line on which a sailboat can sail directly to its target without tacking.
To prepare a boat for winter storage.
The position of an item.
The direction in which a stranded rope is twisted.
A small aft storage space for spare parts and other items.
A line attached to the boom to prevent it from accidentally jibbing.
Lines running from above the main sail to the boom to aid in the lowering of the sail, keeping the sail flaked and off of the deck.
A line led to a sail, but is not currently in use. The line currently in use is known as the working sheet. Usually the working and lazy sheets change when the boat is tacked.
A line with a weight on the end used to measure depth. The lead is dropped into the water and marks on the line are read to determine the current water depth. The lead usually has a cavity to return a sample of the bottom type (mud, sand, etc.)
Lights that are separated in distance so that when they are lined up with one behind the other they provide a bearing. Usually used to enter a harbor or navigate a channel.
Unlit navigational aids for use during the day. Like leading lights, they mark a bearing to a channel when they are lined up one above the other.
3 nautical miles.
The tendency, if any, for a sailboat to want to steer away from the direction of the wind. The opposite condition is known as weather helm.
The shore that the wind is blowing toward. It is important to keep distance from the lee shore because the boat will be blown toward it if control of the vessel is lost.
The direction that the wind is blowing toward. The direction sheltered from the wind.
Boards projecting into the water from the lee side of a vessel to help keep it from slipping sideways in the water when traveling across the wind, similar in intent to a keel.
A board placed on the side of a berth to keep the occupant from falling out.
A line used to tighten the leech of a sail, helping to create proper sail shape.
The aft edge of a fore and aft sail.
Cloths raised along the side of a berth to keep the occupant from falling out.
The direction away from the wind. Opposite of windward.
The sideways movement of a boat away from the wind, usually unwanted. Keels and other devices help prevent a boat from having excessive leeway.
A pilot with a license stating that they are qualified to guide vessels in a particular area.
Where an object is.
To put an object in place.
A small boat used for emergencies such as when the parent boat is sinking.
A device used to keep a person afloat. Also called a life preserver, life vest, PFD or personal floatation device.
A device used to keep a person afloat. Also called a life jacket, life vest, PFD or personal floatation device.
An emergency raft used in case of serious problems to the parent vessel, such as sinking.
A device used to keep a person afloat. Also called a life jacket, life preserver, PFD or personal floatation device.
A line running between the bow and the stern of a boat to which the crew can attach themselves to prevent them from being separated from the boat.
A list of lights arranged in geographical order.
A lit navigational aid such as a lighthouse that can be used at night or in poor visibility.
A navigational light placed on a structure on land. The supporting structure was a house in which the person that maintained the light lived. Most modern lighthouses no longer have living areas.
A light placed on a ship. The ship remained in a fixed position. Most lightships have been replaced by lit buoys or other structures.
Danforth anchor. It has pivoting flukes that dig into the ground as tension is placed on the anchor. It does not have a stock.
A hole in between compartments in the bottom of the boat to allow water to flow into the bilge where it is sent overboard.
On a boat most ropes are called lines.
A device used to keep a line from slipping, such as a jam cleat.
LPG or propane for short. Propane is a common fuel used for cooking and heating. CNG (natural gas) is considered safer because propane is heavy than air and will sink into the bilge if it leaks, creating the potential for an explosion. Propane is more easily available throughout the world than CNG however, so it is used for most boats outside of North America.
A leaning to one side when not underway. Usually the result of an improperly loaded boat. Heeling is different from a list because it is caused by the forces of wind acting upon a sailboat that is underway. When a boat changes tacks, the direction of the heel will change sides, whereas a list is a continual leaning to the same side under any condition.
Length overall. The total length of a boat including bowsprits or other items projecting from the bow or the stern of the boat.
A device that allows boats to pass between bodies of water having different water levels, such as in a canal. A boat enters a lock, then large doors close behind it. The water level is then either raised or lowered until a second set of doors can be opened and the boat can pass through.
Any storage place on a boat. See also chain locker, hanging locker, and wet locker.
A device used to measure the distance traveled through the water. The distance read from a log can be affected by currents, leeway and other factors, so those distances are sometimes corrected to a distance made good. Logs can be electronic devices or paddle wheels mounted through the hull of the boat or trailed behind it on a line.
A written record of a boat's condition, usually including items such as boat position, boat speed, wind speed and direction, course, and other information.
A book in which the boat's log is kept. Each entry usually contains the time and date of the entry, weather conditions, boat speed and course, position and other information and observations.
A method of splicing two lines of identical thickness by unwrapping strands and braiding the lines back together. Long splices have the advantage of being able to fit through blocks and other devices, but are not as strong as other methods of joining lines.
Imaginary lines drawn through the north and south poles on the globe used to measure distance east and west. Greenwich England is designated as 0° with other distances being measured in degrees east and west of Greenwich. For example the center of California, USA is approximately 120° west and the center of Australia is around 135° east. Also see latitude.
A person designated to watch for other vessels and hazards.
A sail whose foot (bottom) is not attached to a boom or other rigid object. The opposite of club footed.
An electronic instrument using radio waves from various stations to find one's position. The LORAN system is being replaced by the GPS system and will be obsolete in a few years. Many LORAN stations have already stopped providing service.
The point of a tide when the water is the lowest. The opposite of high tide.
Used in meteorology to describe an area of low atmospheric pressure.
Liquid petroleum gas or propane. Propane is a common fuel used for cooking and heating. CNG (natural gas) is considered safer because propane is heavy than air and will sink into the bilge if it leaks, creating the potential for an explosion. Propane is more easily available throughout the world than CNG however, so it is used for most boats outside of North America.
A mark on a compass used to read the heading of a boat.
Bolt rope. A rope in the luff of a sail. The luff rope is usually used to attach the sail to a mast.
The edge of a sail toward the bow of a boat.
A term used to describe that edge when the airflow around it stalls. (see luffing)
A description of a flapping motion along the luff (leading edge) of a sail. A sail begins to luff when the air flow stalls when traveling across the sail. Luffing is a sign that the sail is not properly trimmed or that the boat is trying to sail too close to the eye of the wind (pinching.)
Metal or plastic pieces attached to a sail's luff that slide in a mast track to allow easy hoisting of the sail.
A period of no wind. Lulls may be followed by a significant change of wind speed and direction.
Load waterline or length waterline. Also design waterline (DWL.) This is the length of the boat at the waterline when loaded to its designed capacity.
A boat that is letting herself be subjected to prevailing conditions without the use of sails or other devices. Lying ahull is usually not preferred to other actions because a boat may tend to lie with her beam to the waves and the wind (parallel to the waves.) This can cause a boat to roll excessively and even become knocked down.
A boat that is almost stopped with her bow into the wind, probably with the aid of a sea anchor.
The bearing of an object after magnetic variation has been considered, but without compensation for magnetic deviation.
The course of a vessel after magnetic variation has been considered, but without compensation for magnetic deviation.
Compass error. The difference between the reading of a compass and the actual magnetic course or bearing due to errors in the compass reading. These errors can be caused by metals, magnetic fields and electrical fields near the compass. Prior to using a compass, magnetic deviation should be recorded for many different points on the compass as the error can be different at different points. The act of checking for magnetic deviation is called swinging.
The direction to which a compass points. Magnetic north differs from true north because the magnetic fields of the planet are not exactly in line with the north and south poles. Observed differences between magnetic and true north is known as magnetic variation.
The difference between magnetic north and true north, measured as an angle. Magnetic variation is different in different locations, so the nearest compass rose to each location on a chart must be used.
The tallest (or only) mast on a boat.
A topsail on the main mast.
The main sail that is suspended from the main mast.
The line used to control the mainsail.
To attach a line to something so that it will not move.
Moving through the water.
A place where boats can find fuel, water and other services. Marinas also contain slips where boats can stay for a period of time.
Marks used on a lead line or anchor rode indicating the length of the line at that point.
A buoy or other object used to mark a location.
To wrap a small line around another.
A small line used for whipping, seizing, and lashing.
A pointed tool used to separate the strands of a rope or wire.
A protective cover wrapped around the mast at the deck on a keel stepped boat to prevent water from entering the boat.
A box where a deck stepped mast is stepped.
Supporting structures to take the load of the mast at the deck.
The place that supports the bottom of the mast. The mast step usually has a built in pattern fitting a matching pattern on the bottom of the mast, enabling the mast to be accurately positioned.
A track or groove in the back of the mast to which the sail is attached by means of lugs or the bolt rope.
Any vertical spar on the boat that sails are attached to. If a boat has more than one mast, they can be identified by name.
The person in charge of a vessel. The captain.
Also known as a steaming light. The masthead light is a white light that is visible for an arc extending across the forward 225° of the boat. When lit the masthead light indicates that a vessel under power, including sailboats with engines running. Masthead lights are usually located halfway up the mast rather than at the top.
The top of a mast. Wind direction indicators and radio antennas usually collect on the masthead.
An assistant to the captain.
An internationally recognized distress signal used on a radio to indicate a life threatening situation. Mayday calls have priority over any other radio transmission and should only be used if there is an immediate threat to life or vessel. Mayday comes from the French "M'aidez" which means "help me." For urgent situations that are not immediately life threatening there is the PAN PAN identifier. Less urgent messages such as navigational hazards should send a SECURITE message.
A figure representing the average low tide of a region.
In an area with two tides, this figure represents the average of the lowest of the low tides.
Average.
A course marked by buoys or ranges measuring one nautical mile. Measured miles are used to calibrate logs.
A method of docking with a boat's stern to the dock.
A type of projection of the globe used when making charts. Since the world is a sphere, it is impossible to draw accurate charts on flat paper. A Mercator projection shows all of the meridians as straight vertical lines rather than lines that would intersect. This is the type of projection used on a typical world map, but the distances become very distorted near the poles.
A longitude line. Meridians are imaginary circles that run through both poles.
A small line used to pull a heavier line or cable. The messenger line is usually easier to throw, lead through holes or otherwise manipulate than the line that it will be used to pull.
The study of weather.
A red and white vertically striped buoy used in the United States to mark the middle of a channel. Midchannel buoys may be passed by on either side. Also see nun and can buoys.
A place on a boat where its beam is the widest.
Distance at sea is measured in nautical miles, which are about 6067.12 feet, 1.15 statute miles or exactly 1852 meters. Nautical miles have the unique property that a minute of latitude is equal to one nautical mile (there is a slight error because the earth is not perfectly round.) Measurement of speed is done in knots where one knot equals one nautical mile per hour.
A statute mile is used to measure distances on land in the United states and is 5280 feet.
A unit of pressure used to measure the pressure of the atmosphere. 1 millibar equals 0.03 inches of mercury.
When used to measure location a minute is one sixtieth of one degree. One minute of latitude is equal to one nautical mile. Each minute is divided into sixty seconds.
When measuring time a minute is one sixtieth of one hour.
A smaller aft mast on a ketch or yawl rigged boat.
The sail on the aft mast of a ketch or yawl rigged sailboat.
A small sail that is sometimes placed forward of the mizzen mast.
A large heavy knot usually made in the end of a heaving line to aid in accurate throwing.
A boat that has only one hull, as opposed to multihull boats such as catamarans or trimarans.
To attach a boat to a mooring, dock, post, anchor, etc.
A buoy marking the location of a mooring. Usually attached to an anchor by a small pendant.
A line used to secure a boat to an anchor, dock, or mooring.
A place where a boat can be moored. Usually a buoy marks the location of a firmly set anchor.
A code that uses dots and dashes to communicate by radio or signal lights.
A boat designed to use its motor for significant amounts of time and use the sails less often than a normal sailboat.
An engine.
The act of using an engine to move a boat.
An attachment point for another object.
The act of putting an object on its mount.
A line used to reeve lines.
Any boat with more than one hull, such as a catamaran or trimaran.
A type of anchor with a heavy inverted mushroom shaped head. Mushroom anchors are used to anchor in mud and other soft ground.
Short for compressed natural gas or CNG. A type of compressed gas used as fuel for stoves and heaters. CNG is stored in metal cylinders prior to use. CNG is considered safer than other types of fuel such as propane (LPG) because it is lighter than air and may rise into the sky in the event of a leak. Caution should still be used as CNG can collect near the cabin ceiling, potentially causing an explosion. Propane is available in more areas around the world than CNG so CNG is not often used outside of North America.
An annually published book that contains information about the position of the sun, moon, planets and stars. This information is used for celestial navigation.
Distance at sea is measured in nautical miles, which are about 6067.12 feet, 1.15 statute miles or exactly 1852 meters. Nautical miles have the unique property that a minute of latitude is equal to one nautical mile (there is a slight error because the earth is not perfectly round.) Measurement of speed is done in knots where one knot equals one nautical mile per hour. A statute mile is used to measure distances on land in the United states and is 5280 feet.
Having to do with boats, ships, or sailing.
Water of sufficient depth to allow a boat to travel through it.
Lights on a boat help others determine its course, position and what it is doing. Boats underway should have a red light visible from its port bow, a green light on the starboard bow and a white light at its stern. Other lights are required for vessels under power, fishing, towing, etc.
The rules concerning which vessel has the right of way if there is a possibility of collision between two or more boats. The United States Inland Rules of the Road and International Rules of the Road are slightly different.
The act of determining the position of a boat and the course needed to safely move the boat from place to place.
Any fixed object that a navigator may use to find his position, such as permanent land or sea markers, buoys, radio beacons, and lighthouses.
The person responsible for navigating a boat.
The tide with the least variation in water level, occurring when the moon is one quarter and three quarters full. The lowest high tide and the highest low tide occur at neap tide. The opposite is the spring tide.
A sighting taken for celestial navigation at noon, when the sun is at its highest point in the sky.
The "top" point of the line about which the earth rotates.
Polaris, the North Star, is visible in the northern hemisphere and indicates the direction of north. In the southern hemisphere the Southern Cross is used to find the direction of south.
Wind coming from the north.
One of the 4 cardinal compass points. North is the direction toward the North Pole and is at 0° on a compass card.
Official notices reporting changes to charts and other navigational and safety items.
A conical buoy with a pointed top, painted red, and having an even number, used in the United States for navigational aids. At night they may have a red light. These buoys should be kept on the right side of the boat when returning from a larger body of water to a smaller one such as a marina. Can buoys are used on the opposite side of the channel. Also see green and red daymarks.
A stick with a blade at the end used to row a rowboat. Oars are different than paddles because they have a provision to be secured to the rowboat for rowing, such as an oarlock.
A device to attach oars to a rowboat, allowing the operator to row rather than paddle the boat.
A position or fix determined by observing landmarks or other objects to find the position.
A navigational light which turns on and off in a regular pattern, but is on more than it is off. The opposite of a blinking light.
The large body of salt water covering seven tenths of the earth.
The Atlantic, Pacific, Indian, and Arctic Oceans.
Sailing with the wind coming from the stern or quarter of the boat.
Wind that is blowing away from the land, towards the water.
Away from land, toward the water. See inland.
To the side of the boat at right angles, abeam.
To the bow of the boat, forward of the beam.
To the stern of the boat, aft of the beam.
Sailing close hauled. Sailing toward the wind as much as possible with the wind coming from the bow.
A location that is not sheltered from the wind and seas. An open location would not make a good anchorage.
Sails that are not properly arranged for the point of sail that the boat is on. The sails may be luffing or have improper sail shape, or the boat may be heeling too much. These conditions will slow the boat down.
An engine used to power a small boat. Outboard engines are mounted on a bracket aft of the stern of the boat.
On the side of the hull that the water is on. Outboard engines are sometimes just called outboards.
A line used to tension the foot of a sail, used to maintain proper sail shape.
A floatation device attached to one or both sides of the hull to help prevent a capsize.
The total length of the boat, including any object protruding from the bow or the stern. Also known as LOA.
In the water outside of the vessel.
Dangerously steep and breaking seas due to opposing currents and wind in a shallow area.
The area of the bow or stern which hangs over the water.
A line that becomes improperly wrapped over itself and fouls a winch.
A boat owner's private pennant.
A small fitting with a hole used to guide a line.
A stick with a blade in the end of it used to propel a small boat through the water.
The act of using a paddle to propel a boat.
A painted line on the side of a boat at the waterline. The color usually changes above and below the waterline as the boat is painted with special antifouling paint below the waterline.
A line attached to the bow of a dinghy and used to tie it up or tow it.
A tool worn on the hand with a thimble shaped structure on it and used when sewing sails.
An urgent message used on a radio regarding the safety of people or property. A PAN PAN message is not used when there is an immediate threat to life or property, instead the MAYDAY call is used. PAN PAN situations may develop into MAYDAY situations. As with a MAYDAY, PAN PAN messages have priority on the radio channels and should not be interrupted. In the case of a less urgent safety message, such as a hazard to navigation, the appropriate signal to use is SECURITE.
An emergency signal flare that will float down on a parachute after launch, hopefully improving its visibility.
Sometimes used to describe a spinnaker.
Error that can be introduced when not reading an instrument directly from its front, due to the separation of the indicator and the scale being read.
A navigational tool used to move a line on a chart from one location to another without changing its angle, such as when moving a plotted course to a compass rose. Parallel rules are two straight edges that are mechanically connected such that both edges always remain parallel. Lines can then be "walked" across a flat chart.
Latitude lines.
Material wrapped around a line to prevent chaffing.
A clip at the end of a spinnaker pole to hold the guy.
Supporting structures used to support areas where high loads come through openings in the deck, such as at the mast boot.
A journey from one place to another.
A type of log that uses a counter attached to a rotor on a line which is towed behind the boat to help measure distance and speed.
To let out.
The column that the wheel is mounted on.
A card marked in degrees and having sightings on it that is used to take bearings relative to the ship, rather than magnetic bearings as taken with a compass.
A small line attached to a mooring chain. Also sometimes called a pennant.
A small flag, such as can be used for signaling. Flags can be used together to spell words or individually as codes, such as the quarantine flag.
A small line attached to a mooring chain, sometimes called a pendant.
PFD for short. A device used to keep a person afloat. Also called a life jacket, life preserver or life vest.
Personal Floatation Device. A device used to keep a person afloat. Also called a life jacket, life preserver or life vest.
A place extending out into the water where vessels may dock. Usually made out of wood or cement.
A pole embedded in the sea bottom and used to support docks, piers and other structures.
An individual with specific knowledge of a harbor, canal, river or other waterway, qualified to guide vessels through the region. Some areas require that boats and ships be piloted by a licensed pilot.
The act of guiding a vessel through a waterway.
Steering a sailboat too close to the eye of the wind, causing the sails to luff.
A pin used to attach a stern mounted rudder. The hole that the pin fits is known as a gudgeon.
When a boat's stern is thrown over its bow.
A fore and aft rocking motion of a boat. Also see roll and yaw.
How much a propeller is curved.
A material used to seal cracks in wooden planks.
A hull design that is capable of planing.
The speed needed for a boat to begin planing. A boat rising slightly out of the water so that it is gliding over the water rather than plowing through it.
Wood strips used to cover the deck or hull of a wooden vessel.
To find a ship's actual or intended course or mark a fix on a chart.
Also called a CQR or coastal quick release anchor. An anchor that is designed to bury itself into the ground by use of its plow shape.
A tapered device, usually made from wood or rubber, which can be forced into a hole to prevent water from flowing through it. Plugs should be available to fit every through hull.
The act of using anything to stop the water from flowing through a hole.
The position of a sailboat in relation to the wind. A boat with its head into the wind is known as "head to wind" or "in irons". The point of sail with the bow of the boat as close as possible to the wind is called close hauled. As the bow moves further from the wind, the points of sail are called: close reach, beam reach, broad reach, and running. The general direction that a boat is sailing is known as its tack.
To sail as close as possible to the wind. Some boats may be able to point better than others, sailing closer to the wind.
The named directions on a compass such as north, northeast, etc.
Polaris, the North Star, is visible in the northern hemisphere and indicates the direction of north. In the southern hemisphere the Southern Cross is used to find the direction of south.
A spar. Such as a pole used to position a sail.
One of the two points around which the earth spins, known as the north and south poles.
One of the two points that the earth's magnetic field emits from, the magnetic north and south poles.
A boat's aft deck.
A wave that breaks over the stern of the boat.
A sailboat sailing on a tack with the wind coming over the port side and the boom on the starboard side of the boat. If two boats under sail are approaching, the one on port tack must give way to the boat on starboard tack.
The left side of the boat from the perspective of a person at the stern of the boat and looking toward the bow. The opposite of starboard.
A place where ships go to dock.
A porthole. A window in the side of a boat, usually round or with rounded corners. Sometimes portholes can be opened, sometimes they are fixed shut. Also see hatches
A port. A window in the side of a boat, usually round or with rounded corners. Sometimes portholes can be opened, sometimes they are fixed shut. Also see hatches.
A mark of PD made on a chart when plotting a boat's position to indicate that there is reason to doubt that the fix is accurate.
The action of a boat's bow repeatedly slamming into oncoming waves.
A type of dinghy with a flat bow.
Also known as a junction buoy. A red and green horizontally striped buoy used in the United States to mark the separation of a channel into two channels. The preferred channel is indicated by the color of the uppermost stripe. Red on top indicates that the preferred channel is to the right as you return. Also see can and nun buoys.
The typical winds for a particular region and time of year.
A line run forward from the boom to a secure fitting to prevent the boom from jibing accidentally when running. If the boat jibes anyway, this can cause the sail to become backwinded.
The 0° longitude line that runs through Greenwich, England.
The vessel that is required to maintain its course and speed when boats are approaching each other according to the navigation rules. Also known as the stand on vessel.
Slang for propeller.
Also known as LPG (liquid petroleum gas). Propane is a common fuel used for cooking and heating. CNG (natural gas) is considered safer because propane is heavy than air and will sink into the bilge if it leaks, creating the potential for an explosion. Propane is more easily available throughout the world than CNG however, so it is used for most boats outside of North America.
The spinning shaft from the engine to which the propeller is attached.
An object with two or more twisted blades that is designed to propel a vessel through the water when spun rapidly by the boat's engine.
A navigation tool used to measure angles on a chart.
The part of the bow forward of where it leaves the waterline.
A sturdy railing around the deck on the bow.
Removing waste from a holding tank.
Two or more blocks connected to provide a mechanical advantage when lifting heavy objects.
Also called stern pulpit. A sturdy railing around the deck at the stern.
A device connected to the rudder that the steering cables attach to.
The Quebec pennant is flown when first entering a country, indicating that the people on the ship are healthy and that the vessel wants permission to visit the country.
The side of a boat aft of the beam. There are both a port quarter and a starboard quarter.
A sea which comes over the quarter of the boat.
Sleeping areas on the boat.
Also a wharf. A section parallel to the shore for docking and unloading vessels.
A navigational aid with a light that flashes about once per second.
An arch to mount the radar, usually at the stern of the boat.
An object designed to increase the radio reflectivity of a boat so that it is more visible on radar. Many small boats are made with fiberglass and other materials that do not reflect radar very well on their own.
Radio detection and ranging. An electronic instrument that uses radio waves to find the distance and location of other objects. Used to avoid collisions, particularly in times of poor visibility.
A navigational aid that emits radio waves for navigational purposes. The radio beacon's position is known and the direction of the radio beacon can be determined by using a radio direction finder.
A bearing taken with a radio direction finder toward a radio beacon.
RDF for short. An instrument that can determine the direction that a radio transmission is coming from. The RDF is used with a radio beacon to find a radio bearing to help determine the vessel's position.
An instrument that uses radio waves to communicate with other vessels. VHF (very high frequency) radios are common for marine use, but are limited in range. Single side band (SSB) radios have longer ranges.
Invisible waves in the electromagnetic spectrum that are used to communicate (radio) and navigate (radar, RDF.)
A small flat boat, usually inflatable.
To moor with more than one boat tied together, usually using only one boat's ground tackle.
The edge of a boat's deck.
A measurement of the top of the mast's tilt toward the bow or the stern.
distance a boat can travel with its available fuel and supplies.
The difference between high and low tides.
Two lights or daymarks that can be aligned with one behind another to indicate that one is positioned on a line on a chart, typically used to guide a boat into a channel.
Small lines tied between the shrouds to use as a ladder when going aloft.
Radio direction finder. An instrument that can determine the direction that a radio transmission is coming from. The RDF is used with a radio beacon to find a radio bearing to help determine the vessel's position.
Any point of sail with the wind coming from the side of the boat. If the wind is coming from directly over the side, it is a beam reach. If the boat is pointed with its bow more directly into the wind it is a close reach. If the wind is coming from over the quarter, it is called a broad reach.
A bearing 180° from the other. A direction directly opposite the original direction.
A nun buoy. A conical buoy with a pointed top, painted red, and having an even number, used in the United States for navigational aids. At night they may have a red light. These buoys should be kept on the right side of the boat when returning from a larger body of water to a smaller one such as a marina. Can buoys are used on the opposite side of the channel. Also see green and red daymarks.
A navigational aid used in the United States and Canada to mark a channel. Red square daymarks should be kept on the right when returning from a larger to smaller body of water. Green daymarks mark the other side of the channel. Also see can and nun buoys.
Reinforced cringles in the sail designed to hold the reefing lines when reefing the sail.
Also known as the square knot. This knot is an unreliable knot used to loosely tie lines around the bundles of sail that are not in use after reefing.
Points where lines have been attached to tie the extra sail out of the way after reefing.
To partially lower a sail so that it is not as large. This helps prevent too much sail from being in use when the wind gets stronger.
A line of rock and coral near the surface of the water.
Lines used to pull the reef in the sail. The reef line will pass through reef cringles, which will become the new tack and clew of the reefed sail.
Leading a line through a block or other object.
A series of boat races.
A bearing relative to the boat or another object, rather than a compass direction.
A line that passes through all meridians at the same angle. When drawn on a Mercator chart, the rhumb line is a straight line. However the Mercator chart is a distortion of a round globe on a flat surface, so the rhumb line will be a longer course than a great circle route.
To weather a storm, either at sea or at anchor.
Anchor light. A white light displayed from the top of the mast to indicate that the boat is at anchor.
Also called a stability sail or steadying sail. Any small sail set to help the boat maintain its direction without necessarily moving, as when at anchor or in heavy weather.
A combination of sails and spars.
To prepare the rig before sailing.
The wires, lines, halyards and other items used to attach the sails and the spars to the boat. The lines that do not have to be adjusted often are known as standing rigging. The lines that are adjusted to raise, lower and trim the sails are known as running rigging.
To return a boat that is not upright to its upright position.
A small inflatable boat that has a solid hull but has buoyancy tubes that are inflated to keep it afloat.
A curve out from the aft edge (leech) of a sail. Battens are sometimes used to help support and stiffen the roach.
A region between 40° south and 50° south where westerly winds circle the earth unobstructed by land.
Anchor rode. A line or chain attached to the anchor.
A side to side motion of the boat, usually caused by waves. Also see pitching and yawing.
A method of storing a sail usually by rolling the jib around the headstay or the mainsail around the boom or on the mast.
A system of reefing a sail by partially furling it. Roller furling systems are not necessarily designed to support the loads of reefing.
A knot used to attach a line to a spar or similar object.
Traditionally a line must be over 1 inch in size to be called a rope.
A method of moving a boat with oars. The person rowing the boat faces backwards, bringing the blade of the oars out of the water and toward the bow of the boat. They then pull the oars through the water toward the stern of the boat, moving the boat forward.
A small boat designed to be rowed by use of its oars. Some dinghies are rowboats.
A rail on the outside of the hull of a boat to protect the hull from rubbing against piles, docks and other objects.
The post that the rudder is attached to. The wheel or tiller is connected to the rudder post.
A flat surface attached behind or underneath the stern used to control the direction that the boat is traveling.
The rules concerning which vessel has the right of way if there is a possibility of collision between two or more boats. The United States Inland Rules of the Road and International Rules of the Road are slightly different.
To take a boat into water that is too shallow for it to float in, i.e: the bottom of the boat is resting on the ground.
Also known as running backstays. Adjustable stays used to control tension on the mast.
Also known as runners. Adjustable stays used to control tension on the mast.
A type of knot that tightens under load. It is formed by running the standing line through the loop formed in a regular bowline.
A fix taken by taking bearings of a single object over a period of time. By using the vessel's known course and speed, the location of the vessel can be found.
Navigational lights that are required to be used when a vessel is in motion.
The lines and wires (rigging) that are used to raise, lower and adjust the sails.
A point of sail where the boat has the wind coming from aft of the boat. Running can cause the danger of an accidental jibe.
Used to describe a line that has been released and is in motion.
A distance that needs to be kept between the mast and overhead electrical lines to prevent electrical arcing.
A device worn around a person's body that can be attached to jack lines to help prevent a person from becoming separated from the boat.
Any pin that is used to prevent a fitting from falling open.
A pin used to keep the anchor attached to its anchor roller when not in use.
The shape of a sail, with regard to its efficiency. In high winds a sail would probably be flatter, in low winds rounder. Other circumstances can cause a sail to twist. Controls such as the Cunningham, boom vang, outhaul, traveler, halyards, leech line, sheets, and the bend of the mainmast all can affect sail shape. Also see sail trim.
A slot into which the bolt rope or lugs in the luff of the sail are inserted to attach the sail. Most masts and roller reefing jibs use sail tracks. Systems with 2 tracks can allow for rapid sail changes.
The position of the sails relative to the wind and desired point of sail. Sails that are not trimmed properly may not operate efficiently. Visible signs of trim are luffing, excessive heeling, and the flow of air past telltales. Also see sail shape.
A large piece of fabric designed to be hoisted on the spars of a sailboat in such a manner as to catch the wind and propel the boat.
The act of using the wind to propel a sailboat.
A boat which uses the wind as its primary means of propulsion.
A fabric, usually synthetic, used to make sails.
Books that describe features of particular sailing areas, such as hazards, anchorages, etc.
A strong post used for to attach lines for towing or mooring.
An area in shallow water where wave or current action has created a small, long hill of sand. Since they are created by water movement, they can move and may not be shown on a chart.
Navigation using information transmitted from satellites. See Global Positioning System.
To climb.
The distance that the trough of a wave is below the average water level. With large waves in shallow water the scend is important to help determine whether a boat will run aground.
A sailboat with two or more masts. The aft mast is the same size or larger than the forward one(s). Also see ketch and yawl.
The length of the anchor rode relative to the depth of the anchor. For example 100 feet of anchor rode in 20 feet of water would be a scope of 5:1. A scope of 7:1 or more is usually used depending on the holding ground. Too little scope can cause the anchor to drag. Increased scope increases the swinging room.
A boat with a flat bottom and square ends.
A propeller or type of fastener.
To run before the wind in a storm. A method of moving a boat by using a single oar at the stern.
An opening through the toe rail or gunwale to allow water to drain back into the sea.
To sink a boat.
Gossip. People talking about things that may or may not be true, usually about other people or events. The term scuttlebutt evolved from the name of a keg containing water and alcohol that sailors used to gather about before meals.
A drogue designed to bring a boat to a near stop in heavy weather. Typically a sea anchor is set off of the bow of a boat so that the bow points into the wind and rough waves.
The last buoy as a boat heads to sea.
A valve used to prevent water from entering at a through hull.
A boat that comfortable in rough weather.
The average level of the oceans, used when finding water depths or land elevations.
Room for a boat to travel without danger of running aground.
A body of salt water. A very large body of fresh water.
Any body of salt water when talking about its condition or describing the water around a boat. Heavy seas for example.
A vessel designed to be able to cross oceans.
The ability of a person to motor or sail a vessel, including all aspects of its operation.
A port that is not directly listed in the tide tables but for which information is available as a difference from a nearby standard port.
A navigational light that is visible only for a specific sector or arc of a circle, enabling a boat to determine that it lies within that sector. Sector lights might mark the entrance to a channel.
An arc of a circle in which certain types of navigational lights known as sector lights are visible.
To make fast. To stow an object or tie it in place.
A type of warning message transmitted by radio. Securite messages are used to warn of impending storms, navigational hazards and other potential problems that are not immediately life threatening by themselves. MAYDAY and PAN PAN are used for more immediate problems.
Tying two lines, or a spar and a line together, by using a small line.
Said of an area, such as the cockpit, that is capable of rapidly draining away any water that may fill the area.
A locker or other area equipped with a drain capable of allowing any water that may collect in it to leave, such as from wet clothes or equipment.
A device used to keep a sailboat on the same heading relative to the wind without aid of a person. Self steering gear is a mechanical system using a wind vane instead of electrical power as does an autopilot.
A method of signaling using two flags held in position by the signaler.
A weight hung from the anchor chain in order to keep the anchor lying as flat as possible to prevent dragging.
A region drawn on a chart to separate two lanes that have shipping vessels moving in opposite directions.
To wind small line around a rope to protect it from chaffing and weather.
To put an object in place, as in "set the anchor."
The manner in which an object is in place. "Are the sails set correctly?"
The direction that a current is moving.
A navigational instrument used to determine the vertical position of an object such as the sun, moon or stars. Used with celestial navigation.
A metal U-shaped connector that attaches to other fittings with the use of a pin that is inserted through the arms of the U.
To remove a reef from a sail.
An initial trip with a boat to make sure that everything is operating properly.
The long bar part of an anchor. The flukes are at one end of the shank and the stock is at the other.
All boats are referred to as female. "She is at anchor." "Her sails are set."
A pin attaching one part to another that is designed to break if excessive loads are applied. For example to connect the propeller to the propeller shaft so that the pin can break if the propeller strikes something, preventing damage to the propeller and engine.
A covering to protect the bottom of a boat.
A wheel used to change the direction of a line, such as in a block or at the top of the masthead.
A knot used to temporarily shorten a line.
The top plank on the side of a wooden boat that follows the sheer of the deck.
The fore and aft curvature of the deck.
A sudden change of course.
A type of knot used to tie two lines together.
A line attached to the clew of a sail and is used to control the sail's trim. The sheets are named after the sail, as in jib sheets and main sheet.
A large vessel.
To take an object aboard, such as cargo, or water.
To put items such as oars on the boat when not in use.
Neat, orderly and ready to use.
Shallow water.
An underwater sand bar or hill that has its top near the surface.
The edge of the land near the water.
Where the land meets the water.
A quickly made splice joining two lines together. A short splice is wider than the original line and will not fit through blocks or fairleads.
To push a boat, as from a dock or another boat.
Part of the standing rigging that helps to support the mast by running from the top of the mast to the side of the boat. Sailboats usually have one or more shrouds on each side of the mast.
Green and red lights on the starboard and port sides of the boat required for navigation at night. Each light is supposed to be visible through an arc of 112.5°, beginning from directly ahead of the boat to a point 22.5° aft of the beam.
The tendency of a boat to move sideways in the water instead of along its heading due to the motion of currents or leeway.
Tables containing information about the position of the sun, moon, planets and stars. When using celestial navigation these tables help find the position of a boat.
A halyard used to hoist signal flags.
A type of radio carried on a boat to transmit long distances.
To go to the bottom of the water.
To cause an object to go to the bottom of the water.
A vessel of a similar design to another.
Any flat protrusion on the outside of the hull that is used to support another object such as the propeller shaft or rudder.
A small boat.
The outside surface of a boat. Usually used when describing a fiberglass or other molded hull.
A period of almost no water movement between flood and ebb tides
A line that is loose.
To ease a line.
Also called a lug. Metal or plastic pieces attached to a sail's luff that slide in a mast track to allow easy hoisting of a sail.
Lines used to hoist heavy or awkward objects.
The act of using such lines to hoist heavy or awkward objects.
Ropes used to secure the center of a yard to the mast.
A space between two docks or piers where a boat can be moored.
A style of sailboat characterized by a single mast with one mainsail and one foresail. Also see cutter.
The opening between the jib and the mainsail. Wind passing through this opening increases the pressure difference across the sides of the mainsail, helping to move the boat forward.
Small lines used when whipping and serving.
A metal fitting with a arm that uses a spring to close automatically when connected to another object.
A block that can be opened on one side, allowing it to be place on a line that is already in use.
To suddenly stop or secure a line.
An eye splice that does not use a protective insert.
A floor on a boat.
Signals required by navigation rules describing the type of vessels and their activities during times of fog.
The depth of the water as marked on a chart.
The "bottom" point of the line about which the earth rotates.
Wind coming from the south.
One of the 4 cardinal compass points. South is the direction toward the South Pole and is at 180° on a compass card.
A constellation in the shape of a cross used to determine the direction of the South Pole when traveling in the southern hemisphere.
A tall buoy used as a navigational aid.
A pole used as part of the sailboat rigging, such as masts, booms, spinnaker poles and gaffs.
To relieve someone when taking turns at a task, such as manning the helm.
A ball shaped buoy marking a navigational hazard.
A metal band around a spar with an eye to take the shackles used on the running rigging.
To head up into the wind or loosen a sail, allowing the sail(s) to luff.
A tall cone shaped navigational buoy.
A halyard used to raise the spinnaker.
Also spinnaker lift. A line running from the top of the mast, used to hold the spinnaker pole in place.
Sometimes spinnaker boom. A spar used to extend the foot of the spinnaker beyond the edge of the boat, and to secure the corner of the sail.
A very large lightweight sail used when running or on a broad reach.
A storm jib. A small jib made out of heavy cloth for use in heavy weather. Sometimes brightly colored.
The place where two lines are joined together end to end.
Small spars extending toward the sides from one or more places along the mast. The shrouds cross the end of the spreaders, enabling the shrouds to better support the mast.
Docking lines that help keep the boat from moving fore and aft while docked. The after bow spring line is attached near the bow and runs aft, where it is attached to the dock. The forward quarter spring line is attached to the quarter of the boat, and runs forward, being attached to the dock near the bow of the boat.
The tide with the most variation in water level, occurring during new moons and full moons. This is the time of the highest high tide and the lowest low tide. The opposite of a neap tide.
To begin, as in "to spring a leak."
A sudden intense wind storm of short duration, often accompanied by rain. Squalls often accompany an advancing cold front.
Reef knot. A simple knot that can slip. Often used on sailboats when reefing.
A sailboat having square sails hung across the mast.
A square sail hung from a yard on the mast. Best used when sailing down wind.
Single sideband radio. A type of radio used on a boat to transmit for long distances.
A vertical pole on which flags can be raised.
Ability of a boat to keep from heeling or rolling excessively, and the ability to quickly return upright after heeling.
To stop moving.
Air is sail to stall when it becomes detached from the surface it is flowing along. Usually air travels smoothly along both sides of a sail, but if the sail is not properly trimmed, the air can leave one of the sides of the sail and begin to stall. Stalled sails are not operating efficiently.
A post near the edge of the deck used to support life lines.
The vessel that is required to maintain its course and speed when boats are approaching each other according to the navigation rules. Also known as the privileged vessel.
A port for which information is listed in the tide tables. Other ports known as secondary ports have information listed as a difference from the standard port rather that having complete tables.
The rigging of a boat that does not normally need to be adjusted.
The part of the line that will carry the load after a knot has been tied in it.
A sailboat sailing on a tack with the wind coming over the starboard side and the boom on the port side of the boat. If two boats under sail are approaching, the one on port tack must give way to the boat on starboard tack.
The right side of a boat, from the perspective of a person at the stern of the boat and looking toward the bow. The opposite of port.
Sleeping quarters for the boat's captain or guests.
A mile as measured on land, 5280 feet or 1.6 kilometers. Distances at sea are measured as nautical miles.
Lines running fore and aft from the top of the mast to keep the mast upright. Also used to carry some sails. The backstay is aft of the mast and the forestay is forward of the mast.
A triangular sail similar to the jib set on a stay forward of the mast and aft of the headstay.
Also stability sail or riding sail. Any small sail set to help the boat maintain its direction without necessarily moving, as when at anchor or in heavy weather.
Also known as a masthead light. The steaming light is a white light that is visible for an arc extending across the forward 225° of the boat. When lit the steaming light indicates that a vessel under power, including sailboats with engines running. Steaming lights are usually located halfway up the mast rather than at the top.
Tall and short waves caused by water current and wave directions being opposite to the direction of the wind.
In order for the rudder to be able to properly steer the boat, it must be moving through the water. The speed necessary for control is known as steerage way.
The forward edge of the bow. On a wooden boat the stem is a single timber.
A fitting for the bottom of the mast (mast step.)
The act of placing the foot of the mast in its step and raising the mast.
A mast that is in place is stepped.
Where the mast is stepped, as in keel stepped or deck stepped.
A white running light placed at the stern of the boat. The stern light should be visible through an arc of 135°, to the rear of the boat.
A line running from the stern of the boat to a dock when moored.
Pushpit. A sturdy railing around the deck at the stern.
The aft part of a boat. The back of the boat.
Making way in reverse.
A boat that resists heeling.
A crossbeam at the upper part of an anchor.
A knot used in the end of a line to prevent the end from running through a block or other narrow space. Stopper knots prevent a line that slips from unthreading itself and getting lost.
A mechanical device or knot used to keep a rope from running.
Supplies on a boat.
Sometimes called a spitfire. A small jib made out of heavy cloth for use in heavy weather. Sometimes brightly colored.
The storm jib and storm trysail. Small sails built from heavy cloth for use during heavy weather.
A very strong sail used in stormy weather. It is loose footed, being attached to the mast, but not the boom. This helps prevent boarding waves from damaging the sail or the rigging.
To put something away.
A row of wooden planks on the hull of a wooden boat or fiberglass on a more modern fiberglass boat.
To lower.
A length of line used in connecting two parts of a boat or its rigging. A strainer in the bilge so that the bilge pump doesn't get clogged.
A fitting around the propeller shaft to keep the bearing lubricated and to keep water out of the boat.
Cabins and rooms above the deck of a ship.
The breaking waves and resulting foam near a shore.
The sport of riding breaking waves on a board.
An inspection of a boat to determine its condition.
A person who is qualified to inspect a boat in order to determine its condition.
A mop made from rope.
To use such a mop.
The place between the sheave (roller) and housing of a block, through which the line is run.
To fill with water.
Large smooth waves that do not crest. Swells are formed by wind action over a long distance.
A platform, usually on the transom, allowing swimmers to easily climb back onto a boat.
The act of checking compass readings against known headings in order to determine the compass error.
A bridge that swings away from the waterway so that boats may pass beside it.
The distance a boat can move around its anchor. Swinging room is important because if other boats or objects are within a boat's swinging circle they may collide.
A rotating fitting used to keep a line from tangling.
A hinged support for the bottom of a mast so that the mast can be lowered easily when passing under bridges.
A gauge that measures engine revolutions per minute.
The lower forward corner of a triangular sail
The direction that a boat is sailing with respect to the wind. See also port tack and starboard tack.
To change a boat's direction, bringing the bow through the eye of the wind.
To change a boat's direction, bringing the bow through the eye of the wind.
To tack repeatedly, as when trying to sail to a point up wind of the boat.
Lines used with blocks in order move heavy objects.
A rail around the stern of a boat.
The end of a line.
A line attached to the end of a wire to make it easier to use.
To gather the unused end of a line neatly so that it does not become tangled.
To remove a sail.
To add a reef to a sail.
Also called a Dan buoy. A float with a flag at the top of a pole. Used to mark a position such as for a race or a man overboard.
A metal fitting on the mast that the spreaders are attached to.
A small line free to flow in the direction of the breeze. It is attached to sails, stays in the slot, and in other areas, enabling the helmsman and crew to see how the wind is flowing. Proper use of the telltales can help sailors improve their sail trim.
A small boat used to ferry people and supplies between a larger boat and the shore. See dinghy.
Used to describe a boat that heels easily.
The bottom of the mast, with a shape designed to fit into the mast step.
A metal fitting used to strengthen an eye splice (loop) made in a rope or wire.
The forward upper corner of a four cornered sail known as a gaff rigged sail.
Fittings attached through the hull to which a sea cock and hose, a transducer, or other device is attached. Through hulls are used to expel waste water, such as from a sink, to let sea water in, such as for engine cooling, and to allow placement of sensors such as depth gauges. A sea cock is attached directly to the through hull before any hoses are attached so that the flow of water can be easily shut off if the hose fails. Plugs should be available to force into a through hole in case the through hole fails. Transducers should be equipped with caps to place over the hole should the transducer itself need to be removed.
A seat running across the width a small boat.
Also athwartships. Across the width of a boat.
Small charts showing tidal stream directions and rate of flow.
Also called tidal stream. The flowing of water caused by the rising and lowering tidal waters.
The difference of a tide's high and low water levels.
The flow of water caused by rising and lowering tides.
Tables containing information about the time of the high and low tides and the water level to be expected at that time.
The predictable, regular rising and lowering of water in some areas due to the pull of the sun and the moon. Tidal changes can happen approximately every 6 or 12 hours depending on the region. To find out the time and water levels of different tides, you can use tide tables for your area. The period of high water level is known as high tide and the period of low water level is known as low tide. In the Bay of Fundy, the tidal range exceeds 40 feet (13 meters.)
Also hiking stick. An extension to the tiller allowing the helmsman to steer while hiking. Commonly found on racing boats, they can help improve visibility or stability.
An arm attached to the top of the rudder to steer a small boat. If the helmsman wants to steer to starboard he pushes the tiller to port. Larger boats usually use a wheel instead of a tiller.
Regions of about 15° of longitude around the world where time is measured on a local scale. Each time zone keeps time slightly differently so that at 12:00 noon the sun will be high in the sky. For example at noon in England it is midnight in New Zealand. If New Zealanders kept their clocks set to the English time zone, it would be very dark at noon!
A small rail around the deck of a boat. The toe rail may have holes in it to attach lines or blocks. A larger wall is known as a gunwale.
The weight or displacement of a ship.
A boat that has too much weight up high. This can adversely affect the boat's stability.
A mast on top of another mast.
A mark on the top of a navigational buoy or daybeacon.
A line running from the end of the boom to the top of the mast used to keep the boom from falling when the sail is not set.
A triangular sail set above the gaff on a gaff rigged boat.
The sides of the hull above the waterline and below the deck.
To pull a boat with another boat, such as a tugboat towing a barge.
Running lights that should be used by boats when towing to indicate that a tow is in progress.
The path that a vessel is taking.
A guide in the mast or other spar that accepts lugs to attach a sail.
A rail to which a sliding car is attached for easy adjustment of the position of blocks and lines.
Winds in certain areas known for their consistent strength and direction. Trade winds are named because of their reliability, allowing for planned voyages along the routes favored by those winds.
The aft edge of a sail, more commonly called the leech.
An electronic device that uses sound waves to collect information such as water depth and vessel speed, usually attached to a through hull. The transducer then converts that information to electrical signals that can be used by electronic displays in the cockpit.
Also called a range. Two navigational aids separated in distance so that they can be aligned to determine that a boat lies on a certain line. Transits can be used to determine a boat's position or guide it through a channel.
The aft side of the hull.
A belt and line used to help a crew hike out beyond the edge of a boat to counteract the boat's heel. Usually used on small vessels for racing.
A track or rod with an attached block, allowing more controlled adjustment of a sail's sheet. The traveler allows better control of the sail's shape.
A stay leading from one mast, such as the main mast to another, such as the mizzen mast.
A running light allowed on some sailboats instead of the normal bow and stern lights. The tricolor light contains the red and green side lights and the white stern light in a single fitting that is attached to the top of the mast.
An adjustable section of the rudder that allows the rudder to be corrected for lee helm or weather helm.
To haul in on a sheet to adjust the sail trim.
Sail trim.
A properly balanced boat that floats evenly on its waterline. Improperly trimmed boats may list or lie with their bow or stern too low in the water.
A boat with a center hull and two smaller outer hulls called amas. Also see catamaran and monohull.
A line attached to the end of an anchor to help free it from the ground.
A line 23 degrees, 27 minutes north of the equator. On June 21 the sun is directly above the Tropic of Cancer, at all other times the sun is further south.
A line 23 degrees, 27 minutes south of the equator. On December 22 the sun is directly above the Tropic of Capricorn. At all other times the sun is further north.
The region around the equator between the Tropic of Cancer and the Tropic of Capricorn. The tropics are known for their warm weather.
The bottom of a wave, the valley between the crests.
A cap for the top of the mast.
The course of a boat after being corrected for magnetic deviation and magnetic variation.
Geographic north. Toward the North Pole.
The speed and direction of the wind. The motion of a boat will cause the wind to appear to be coming at a different direction and speed, which is known as apparent wind
The place that the centerboard or daggerboard retracts into.
A hinged fitting at the top of a mast to hold another mast above it.
Also called storm trysail. A very strong sail used in stormy weather. It is loose footed, being attached to the mast, but not the boom. This helps prevent boarding waves from damaging the sail or the rigging.
A small powerful boat used to help move barges and ships in confined areas.
To adjust the standing rigging or other equipment to make a boat perform better.
For a boat to turn completely over such that its mast is pointing down instead of up.
A metal fitting that is turned to tighten or loosen the tension on standing rigging.
The distance required for a boat to turn in a complete circle.
A bag in which a spinnaker or other large sail can be stowed with the lines attached so that it can be rapidly raised.
Small line used for whipping other light duties also known as small stuff.
A knot with two half hitches (loops) on the standing part of the line.
A strong tropical revolving storm of force 12 or higher in the southern hemisphere. Typhoons revolve in a counterclockwise direction. In the northern hemisphere these storms revolve clockwise and are known as hurricanes.
Having no sails up. In heavy weather the windage of the mast and other spars can still be enough to move the boat.
On the lee side of an object, protected from the wind.
A vessel in motion is under way.
Strong offshore current extending to the shore.
To unfold or unroll a sail. The opposite of furl.
To windward, in the direction of the eye of the wind.
United States Coast Guard.
A flat device that is affected by the wind. Vanes are used in wind direction indicators and some self steering gear systems.
A hydraulic ram or block and tackle used to hold the end of the boom down.
A type of propeller that has adjustable blades for varying speeds or directions, and may be able to reduce drag when under sail.
Magnetic variation. The difference between magnetic north and true north, measured as an angle. Magnetic variation is different in different locations, so the nearest compass rose to each location on a chart must be used.
A line drawn to indicate both the direction and magnitude of a force, such as leeway or a current.
A shifting of the wind direction, opposite of backing. Clockwise in the northern hemisphere, counter-clockwise in the southern hemisphere.
Also VMG. Actual boat speed after adjusting for such factors as current and leeway.
The distance between the water level at chart datum and an overhead obstacle such as a bridge or power line.
A navigational aid with a light that flashes between 80 and 159 times per minute. Usually around twice per second.
Very High Frequency radio waves.
A radio that transmits in the VHF range. VHF radios are the most common communications radio carried on boats, but their range is limited to "line of sight" between the transmitting and receiving stations. Also see single sideband.
A bearing taken by visually observing the location of known landmarks.
A fix taken by visually observing the location of known landmarks.
Velocity made good. Actual boat speed after adjusting for such factors as current and leeway.
Waves generated in the water by a moving vessel.
A division of crew into shifts.
The time each watch has duty.
The length of the boat at the waterline.
The line where the water comes to on the hull of a boat. Design waterline is where the waterline was designed to be, load waterline is the waterline when the boat is loaded, and the painted waterline is where the waterline was painted. Actual waterline is where the waterline really is at any given time.
Completely filled with water.
A river, canal or other body of water that boats can travel on.
The progress of a boat. If a boat is moving it is considered to be "making way."
The tendency of a boat to head up toward the eye of the wind. The opposite of lee helm.
To raise, as in to weigh anchor.
Wind coming from west.
One of the 4 cardinal compass points. West is at 270° on a compass card.
A locker equipped with a drain so that wet clothes can be stored in it without damaging other objects in the boat.
The amount of area of the hull, keel, rudder, and other objects that is under water.
Also a quay. A section parallel to the shore for docking and unloading vessels.
One of two methods used to steer a boat. A wheel is turned in the direction that the helmsman wants the boat to go. On smaller boats a tiller is usually used, which steers in the opposite manner.
To bind the strands of a line with a small cord.
A spar used to help hold the jib out when sailing off the wind.
A navigational buoy with a whistle.
To avoid something by a large distance.
A device used to give a mechanical advantage when hauling on the lines.
A funnel used to force wind in a hatch and ventilate the below decks area.
The amount of a boat, sail or other object that the wind can push on.
A mechanical device used to pull in cable or chain, such as an anchor rode.
In the direction of the wind. Opposite of leeward.
A method of running before the wind with two sails set. Usually the mainsail on one side and a headsail on the other, or one headsail on each side.
The sails used on a particular sailboat in normal weather conditions.
The sheet that is currently taught and in use to control a sail. The opposite of the lazy sheet.
A sailboat or powerboat used for pleasure, not a working boat.
The end of a yard.
A spar attached to the mast and used to hoist square sails.
Swinging off course, usually in heavy seas. The bow moves toward one side of the intended course. Also see rolling and pitching.
A two masted sailboat with the shorter mizzen mast placed aft of the rudder post. A ketch is similar, but the mizzen mast is forward of the rudder post.
The point of the celestial sphere which is directly overhead.
A gentle breeze. The west wind.
Used to indicated times measured in Coordinated Universal Time, a successor to Greenwich Mean Time. A time standard that is not affected by time zones or seasons. | 
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Sep 17, 2023 · What is a sloop rig? A sloop rig is a sailboat with one mast and two sails: a mainsail and headsail. It's a simple sail plan that handles well and offers good upwind performance. The sloop rig can be sailed shorthanded and is able to sail very close to the wind, making it very popular. Most recreational sailboats use a sloop rig.
The shape of the sails depends on the rigging, so they overlap a bit. To keep it simple I'll first go over the different sail types based on the most common rig. I'll go over the other rig types later in the article. Bermuda Sloop: the most common rig. Most modern small and mid-sized sailboats have a Bermuda sloop configuration. The sloop is ...
A very strong sail used in stormy weather. It is loose footed, being attached to the mast, but not the boom. This helps prevent boarding waves from damaging the sail or the rigging. Tugboat A small powerful boat used to help move barges and ships in confined areas. Tune To adjust the standing rigging or other equipment to make a boat perform ...
Types of rig (ie the configuration of masts and sails) used on sailing vessels and specific items of rigging used on sailing vessels, from full-rigged ships to sailboats Contents Top
Jun 15, 2022 · Fore-and-aft Rig. This is a sailing rig that chiefly has the sails set along the lines of the keel and not perpendicular to it. It can be divided into three categories: Bermuda rig, Gaff rig, and Lateen rig. Bermuda Rig - Also known as a Marconi rig, this is the typical configuration of most modern sailboats. It has been used since the 17th ...
Jul 26, 2023 · ==Short answer: sailboat rigging types== The most common types of sailboat rigging include sloop, ketch, schooner, and cat rig. A sloop has a single mast with one forestay and one backstay. A ketch has two masts, usually with a taller main mast and a shorter mizzen mast. A schooner has two or more masts of