Glossary
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TermDefinition
- General Nautical Terminology, Weather (Meteorology) Land Breeze
A local wind that blows from the land towards the sea, typically during the night, caused by the differential cooling rates of land and...
More Details - General Nautical Terminology Landfall
The event of a vessel sighting or reaching land after a voyage at sea.
Landfall is a term used in the maritime world to describe the moment...
More Details - General Nautical Terminology LanyardA short length of line used to secure an object such as a knife
- General Nautical Terminology Lash DownTo secure firmly with a rope or line
- General Nautical Terminology, Navigation LAT
The lowest level that sea tides can reach under normal meteorological conditions, based on astronomical influences such as the gravitational pull...
More Details - General Nautical Terminology Lateral MarkBuoy, or post used to mark Port and Starboard sides of a channel
- General Nautical Terminology, Navigation Latitude
The angular distance of a location on Earth's surface, measured in degrees(°), minutes('), and seconds('') north or south of the equator which is...
More Details - General Nautical Terminology Lazarette
A storage compartment located in the stern (aft) of a boat, typically used for stowing gear, equipment, or provisions.
A lazarette is a...
More Details - General Nautical Terminology Lazy JacksA network of cordage rigged to a point on the mast and to a series of points on either side of the boom that cradles and guides the sail onto the... More Details
- Flag / Pennant, Signals & Communication Code Flag Lima (L)

The International Maritime Signal Flag Lima.
Meaning
Stop immediately.
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If appended by a Numeral Pennant, Latitude (the first 2 digits... - General Nautical Terminology Leading LightsLights positioned to assist entry into harbour or safe passage through a channel. Usually one light above another marks the correct course.
- General Nautical Terminology LeadlineAn instrument used in navigation to measure water depth; a line attached to some lead. Usually the line is marked with knots at regular intervals.
- General Nautical Terminology LeagueA unit of length, normally equal to three nautical miles.
- Courses, RYA Learn to WingsurfThe RYA Learn to Wingsurf course introduces participants to the basics of wingsurfing. Participants learn how to control the wing, balance on the... More Details
- General Nautical Terminology LeeThe direction towards which the wind blow
- General Nautical Terminology LeechThe trailing edge of a triangular sail
- General Nautical Terminology Lee-oh!Command given by helm when tacking as the bow passes through the wind. Tells the crew to reset the sails on the new course.
- General Nautical Terminology, Weather (Meteorology) Leeshore
A shoreline that lies downwind of a vessel, posing a potential hazard as the wind pushes the vessel towards it.
A leeshore is a concept in...
More Details - General Nautical Terminology Leeward
The side of a vessel or an object that is sheltered from the wind, opposite to the windward side.
Leeward is a crucial concept for...
More Details - Flag Semaphore, Signals & Communication Letters to Follow (Flag Semaphore)

This flag semaphore signal indicates a change from numbers to letters (Letters to follow). This switches back from numbers to the default...
More Details - Courses, RYA Level 1 Start Powerboating (PB1)The RYA Level 1 Start Powerboating course introduces beginners to the basics of powerboat handling. Participants learn low-speed maneuvers, safety... More Details
- Courses, RYA Level 2 Powerboat Handling (PB2)The RYA Level 2 Powerboat Handling course is a comprehensive two-day program that teaches participants the skills needed to operate powerboats... More Details
- General Nautical Terminology, Safety Life Jacket
A buoyant, wearable safety device designed to keep a person afloat in the water and reduce the risk of drowning.
A life jacket, also known as...
More Details - General Nautical Terminology LifelinePersonal safety device attached to harness on lifejacket and to vessel strongpoint. Designed to keep you on board
- General Nautical Terminology, Safety Liferaft
An inflatable or rigid floating device designed to provide emergency refuge and safety for individuals forced to abandon a vessel at sea.
A...
More Details - General Nautical Terminology Lighthouse
A tall, often cylindrical structure equipped with a powerful light and other navigational aids, built near coastlines or on islands to guide...
More Details - Phonetic Alphabet, Signals & Communication Lima
Pronounced: LEE-mah
The term for the letter L in the NATO Phonetic Alphabet.
- General Nautical Terminology Line
A rope used on a boat for various purposes, such as securing the vessel to a mooring (mooring line), adjusting sails (halyard or sheet), towing...
More Details - General Nautical Terminology, Navigation Lines of Position (LOP)
Navigational lines drawn on a chart, each representing a possible location of a vessel based on a single observation or measurement.
A line...
More Details - General Nautical Terminology ListA permanent lean to one side or the other
- General Nautical Terminology Listing
The condition of a vessel leaning to one side due to an imbalance in weight or external forces.
A vessel lists when it tilts to port or...
More Details - Flag Semaphore, Signals & Communication Letter L (Flag Semaphore)

Flag semaphore indicating the letter L.
- Morse Code, Signals & Communication Letter L (Morse Code)
International Morse Code sequence representing the letter L.
- General Nautical Terminology LNM
A Local Notice to Mariners (LNM) is a publication issued by maritime authorities to provide important information to mariners about navigational...
More Details - General Nautical Terminology Local Notice to Mariners (LNM)
A Local Notice to Mariners (LNM) is a publication issued by maritime authorities to provide important information to mariners about navigational...
More Details - General Nautical Terminology Lock
A gated section of a waterway, such as a canal or river, designed to raise or lower vessels between stretches of water at different levels.
A...
More Details - General Nautical Terminology, Parts of a Boat Locker
A storage compartment or enclosed space on a boat, typically used for stowing equipment, gear, or provisions securely.
A locker on a boat is a...
More Details - General Nautical Terminology Logbook
An official record maintained aboard a vessel that documents the ship's daily activities, including navigational data, weather conditions, and...
More Details - General Nautical Terminology Log Line
A device used historically by mariners to measure a vessel's speed through the water.
The log line consists of a wooden board, known as the...
More Details - General Nautical Terminology Log ReadingThe reading of distance travelled through the water usually taken every hour from the log and recorded in the deck log
- General Nautical Terminology, Navigation Longitude
The geographic coordinate that specifies the east-west position of a point on the Earth's surface, measured in degrees(°), minutes(') and...
More Details - General Nautical Terminology, Safety Look-out
A crew member assigned to maintain a continuous watch for potential hazards, other vessels, or navigational markers while at sea.
A look-out...
More Details - General Nautical Terminology, Navigation LOP
Navigational lines drawn on a chart, each representing a possible location of a vessel based on a single observation or measurement.
A line...
More Details - General Nautical Terminology Lose WayA vessel loses way when she slows down and stops in the water
- General Nautical Terminology, Navigation Lowest Astronomical Tide (LAT)
The lowest level that sea tides can reach under normal meteorological conditions, based on astronomical influences such as the gravitational pull...
More Details - General Nautical Terminology Lubber LineThe marker in the compass which is aligned with the fore-and-aft line of the boat against which the course can be read off on the compass card
- General Nautical Terminology Luff
The leading edge, which is the part of the sail that faces the wind when the sail is set correctly.
The luff of a sail is a critical part of...
More Details - General Nautical Terminology Luff Up
To steer a sailing vessel closer to the wind, reducing the angle between the boat's heading and the direction of the wind.
"Luff up" is a...
More Details - General Nautical Terminology LullA temporary drop in wind speed
- General Nautical Terminology, Weather (Meteorology) Lundy
Sea area of the Met Office Shipping Forecast. Lies in the Bristol Channel, around Lundy Island off southwest England.
Named for Lundy Island...
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