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      All our courses are engaging, interactive and fun! Whether formal training or simply looking to brush up, we take online learning to the next level.

      • Sailing EssentialsFreeA free course great for anyone who spends time on the water.
      • Essential Navigation & SeamanshipRYA course for beginners. Learn charts, tides, pilotage, and core seamanship with simple practice tasks.
      • Day Skipper TheoryMost PopularRYA course for inshore skippers. Plan day passages using chartwork, tides, weather, and COLREGs.
      • Coastal Skipper / Yachtmaster® TheoryComing SoonRYA course for advanced navigation and passage planning. Work with secondary ports, tidal streams, and offshore weather.
      • SRC (VHF) Marine Radio CourseRYA Short Range Certificate radio course. Study online, then take the practical exam with an RYA assessor.
  • Directory

      Are you looking for something nautical related? Our directory is an extensive list of courses and places associated with the marine industry. Hop over and search now.

      • Places
        Find anywhere nautical, including marinas & training centres. If it exists, we’ve got it listed!
      • Courses
        We help you navigate through the complex world of training and help find what’s best for you.
  • Know-How

      We believe every day’s a school day on a boat! That’s why we built Nautical Know-How, dedicated to answering your questions. Even better, if it can’t answer your question immediately, you can request it, and we’ll add it to our knowledge base.

      • Nautical Terms & Terminology
        Understanding the language of the marine world is like trying to learn a pirate’s secret code while juggling fish. Let us explain why a sheet isn’t for your bed, why “heave ho” doesn’t mean throw up (most of the time), and why “dead reckoning” is surprisingly less ominous than it sounds.
      • Why do we have tides?
        Have you ever wondered what causes the tides? Check out this video, which introduces the forces that create the tides we experience on Earth.
      • What causes our weather?
        A video introducing the drivers behind our weather, part of our RYA Day Skipper & RYA Coastal Skipper / Yachtmaster® Offshore theory courses.
      • Buoyage Flashcards
        Flashcards designed to help remember the buoys in the IALA system. If you want to learn them in detail, our module ‘Getting in and out of harbour‘, covers the IALA system and different buoys used.
      • Interactive Rule Book (COLREGs / IRPCS)
        Whether you’re a novice sailor or a seasoned skipper, we can help you navigate the IRPCS confidently and clearly. Our easy-to-use, easy-to-understand, plain English rule book with helpful interpretations of what each rule means.
      • The Salty Sea Blog
        From salty old sea dogs to fresh-faced deckhands, this blog is for anyone who finds peace, adventure, and a bit of mischief on the water. So hoist the main, set your course, and let’s sail into the stories, lessons, and musings that make life on the sea so irresistible.
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Nautical Know How
  • Our Courses

      All our courses are engaging, interactive and fun! Whether formal training or simply looking to brush up, we take online learning to the next level.

      • Sailing EssentialsFreeA free course great for anyone who spends time on the water.
      • Essential Navigation & SeamanshipRYA course for beginners. Learn charts, tides, pilotage, and core seamanship with simple practice tasks.
      • Day Skipper TheoryMost PopularRYA course for inshore skippers. Plan day passages using chartwork, tides, weather, and COLREGs.
      • Coastal Skipper / Yachtmaster® TheoryComing SoonRYA course for advanced navigation and passage planning. Work with secondary ports, tidal streams, and offshore weather.
      • SRC (VHF) Marine Radio CourseRYA Short Range Certificate radio course. Study online, then take the practical exam with an RYA assessor.
  • Directory

      Are you looking for something nautical related? Our directory is an extensive list of courses and places associated with the marine industry. Hop over and search now.

      • Places
        Find anywhere nautical, including marinas & training centres. If it exists, we’ve got it listed!
      • Courses
        We help you navigate through the complex world of training and help find what’s best for you.
  • Know-How

      We believe every day’s a school day on a boat! That’s why we built Nautical Know-How, dedicated to answering your questions. Even better, if it can’t answer your question immediately, you can request it, and we’ll add it to our knowledge base.

      • Nautical Terms & Terminology
        Understanding the language of the marine world is like trying to learn a pirate’s secret code while juggling fish. Let us explain why a sheet isn’t for your bed, why “heave ho” doesn’t mean throw up (most of the time), and why “dead reckoning” is surprisingly less ominous than it sounds.
      • Why do we have tides?
        Have you ever wondered what causes the tides? Check out this video, which introduces the forces that create the tides we experience on Earth.
      • What causes our weather?
        A video introducing the drivers behind our weather, part of our RYA Day Skipper & RYA Coastal Skipper / Yachtmaster® Offshore theory courses.
      • Buoyage Flashcards
        Flashcards designed to help remember the buoys in the IALA system. If you want to learn them in detail, our module ‘Getting in and out of harbour‘, covers the IALA system and different buoys used.
      • Interactive Rule Book (COLREGs / IRPCS)
        Whether you’re a novice sailor or a seasoned skipper, we can help you navigate the IRPCS confidently and clearly. Our easy-to-use, easy-to-understand, plain English rule book with helpful interpretations of what each rule means.
      • The Salty Sea Blog
        From salty old sea dogs to fresh-faced deckhands, this blog is for anyone who finds peace, adventure, and a bit of mischief on the water. So hoist the main, set your course, and let’s sail into the stories, lessons, and musings that make life on the sea so irresistible.
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Sign In Join now—it’s Free

Glossary

Nautical chart abbreviations are like the secret code of the seas—except instead of buried treasure, they lead to rocks, buoys, and mysterious dashed lines that scream, 'Don’t sail here.' Learning them can feel like cracking a pirate’s encrypted diary, but don’t worry, matey! With clever tools, quirky mnemonics, and a splash of humour, we’ll help you go from 'What’s "FOUL" mean? to confidently navigating the “Wk” wrecks and “Fl G” flashes like a salty sea captain. Think of it as Rosetta Stone, but for avoiding sandbanks!
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Results: 46
  • Term
    Definition
  • General Nautical Terminology Gaff

    A spar attached to a mast, used to support the upper edge of a fore-and-aft sail, such as a gaff rigged mainsail or topsail. 

    A gaff is an...

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  • General Nautical Terminology Gaff Rig

    A sailing rig where the sail is four-sided and controlled by a spar (the gaff) at its top, which is hoisted at an angle to the mast.

    A gaff...

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  • Weather (Meteorology) Gale

    Beaufort Scale - Force 8 (Gale Force 8)

    A gale refers to a strong wind between 34 to 40 knots (39 to 46 mph or 63 to 74 km/h) on the Beaufort...

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  • General Nautical Terminology, Parts of a Boat Galley

    The kitchen or cooking area on a ship or boat, typically compact and designed for efficient use of space.

    Unlike a kitchen in a house, the...

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  • Flag / Pennant, Signals & Communication Code Flag Golf (G)

    The International Maritime Signal Flag Golf.

    Meaning

    I require a pilot.
    By fishing vessels: I am hauling nets.
    If appended by a Numeral...

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  • General Nautical Terminology GDOP

    A measure in marine navigation that quantifies the effect of satellite geometry on the accuracy of position determination. It is a factor used to...

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  • General Nautical Terminology, Parts of a Boat Gelcoat

    A specialised resin-based coating applied to the surface of fibreglass boats to provide a smooth, durable, and protective outer layer.

    Gelcoat...

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  • Organisation General Lighthouse Authorities (GLA)

    A term that collectively refers to the three organisations responsible for maintaining maritime navigation aids—such as lighthouses, buoys, and...

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  • General Nautical Terminology Genoa

    A large foresail that overlaps the mainsail, commonly used on sailing yachts to improve speed and performance in light to moderate winds.

    A...

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  • General Nautical Terminology Geometric Dilution of Precision (GDOP)

    A measure in marine navigation that quantifies the effect of satellite geometry on the accuracy of position determination. It is a factor used to...

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  • General Nautical Terminology, Weather (Meteorology) German Bight

    Sea area of the Met Office Shipping Forecast. Located in the southeastern North Sea, off the coast of northern Germany and the...

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  • General Nautical Terminology, Weather (Meteorology) GFS

    A weather model developed by the National Centers for Environmental Prediction (NCEP) that provides global weather forecasts by simulating the...

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  • General Nautical Terminology Gimbal

    A pivoted support that allows an object, such as a compass or a stove, to remain level regardless of the motion of the vessel.

    A gimbal is a...

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  • General Nautical Terminology Give Way

    In a collision situation, one or more vessels are defined as Give Way. The Give Way vessel should alter its course to concede passage to another...

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  • General Nautical Terminology Give Way VesselThe vessel whose duty it is to keep clear of another, she should take early and substantial action to avoid a collision
  • Organisation GLA

    A term that collectively refers to the three organisations responsible for maintaining maritime navigation aids—such as lighthouses, buoys, and...

    More Details
  • General Nautical Terminology Glass Reinforced Plastic (GRP)

    A composite material made of a polymer matrix reinforced with fine glass fibres, commonly used in marine applications for its strength,...

    More Details
  • Flag Semaphore, Signals & Communication Letter G (Flag Semaphore)
    Letter G (Flag Semaphore)

    This shape represents the Letter G (Flag Semaphore) and the Number 7 (Flag Semaphore).

  • Morse Code, Signals & Communication Letter G (Morse Code)

    International Morse Code sequence representing the letter G.

  • General Nautical Terminology, Weather (Meteorology) Global Forecast System (GFS)

    A weather model developed by the National Centers for Environmental Prediction (NCEP) that provides global weather forecasts by simulating the...

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  • General Nautical Terminology, Safety Global Maritime Distress and Safety System (GMDSS)

    An internationally agreed-upon set of safety procedures, communication protocols, and equipment designed to ensure that ships at sea can send and...

    More Details
  • Signals & Communication Global Maritime Distress and Safety System Sea Areas

    A map of the UK indicating the 3 sea areas around the coast and the coast of nearby European countries. White pointers indicate Medium Frequency...

    More Details
  • General Nautical Terminology, Navigation Global Navigation Satellite System (GNSS)

    The collective set of systems that enables positioning devices to calculate latitude & longitude. The system includes solutions including the GPS...

    More Details
  • General Nautical Terminology Global Positioning System (GPS)

    The US-based system of satellites, able to determine the latitude and longitude of a receiver on Earth by calculating the time difference for...

    More Details
  • General Nautical Terminology, Safety GMDSS

    An internationally agreed-upon set of safety procedures, communication protocols, and equipment designed to ensure that ships at sea can send and...

    More Details
  • General Nautical Terminology, Navigation GMT

    The mean solar time at the Prime Meridian in Greenwich, London, used as a global time standard.

    Greenwich Mean Time (GMT) is a timekeeping...

    More Details
  • General Nautical Terminology, Navigation Gnomonic Projection

    A type of map projection where the surface of the Earth is projected onto a plane from the centre of the globe, causing great circles to appear...

    More Details
  • General Nautical Terminology, Navigation GNSS

    The collective set of systems that enables positioning devices to calculate latitude & longitude. The system includes solutions including the GPS...

    More Details
  • General Nautical Terminology Go AboutTo change tack by altering course to bring the wind on the other side
  • General Nautical Terminology Going AsternWhen going backwards through the water you may hear the skipper say: "I am going astern".
  • Phonetic Alphabet, Signals & Communication Golf

    Pronounced: GOLF

    The term for the letter G in the NATO Phonetic Alphabet.

  • General Nautical Terminology Gooseneck

    A pivotal fitting on a sailing vessel that connects the boom to the mast, allowing for controlled movement in multiple directions.

    The...

    More Details
  • General Nautical Terminology Goose-winged

    A sailing configuration where a fore-and-aft rigged vessel's sails are set on opposite sides of the boat, typically with the mainsail on one side...

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  • General Nautical Terminology GPS

    The US-based system of satellites, able to determine the latitude and longitude of a receiver on Earth by calculating the time difference for...

    More Details
  • General Nautical Terminology Grab RailRails fitted above and below decks to grab at when the vessel heels
  • General Nautical Terminology, Navigation Greenwich Mean Time (GMT)

    The mean solar time at the Prime Meridian in Greenwich, London, used as a global time standard.

    Greenwich Mean Time (GMT) is a timekeeping...

    More Details
  • General Nautical Terminology, Weather (Meteorology) GRIB

    A type of data format used in oceanography and meteorology to represent gridded data in a binary form for efficient storage and...

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  • General Nautical Terminology, Weather (Meteorology) GRIdded Binary (GRIB)

    A type of data format used in oceanography and meteorology to represent gridded data in a binary form for efficient storage and...

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  • General Nautical Terminology GroundA general term for the anchors, cables and all the gear required when anchoring
  • General Nautical Terminology GRP

    A composite material made of a polymer matrix reinforced with fine glass fibres, commonly used in marine applications for its strength,...

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  • General Nautical Terminology Guard RailSafety line fitted round the vessel to prevent the crew falling overboard
  • General Nautical Terminology Guardrail

    A safety barrier installed along the edges of a vessel’s deck to prevent crew or passengers from falling overboard.

    This essential feature on...

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  • General Nautical Terminology Gunwale

    The upper edge or rim of a boat's side, often serving as a structural reinforcement and a mounting point for fittings or equipment.

    The term...

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  • General Nautical Terminology Guy

    A rope, wire, or chain used to stabilise or secure a mast, spar, or other structure on a vessel by counteracting lateral forces.

    A guy is a...

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  • General Nautical Terminology Gybe

    A gybe (jibe) is a sailing manoeuvre where a boat changes direction by turning its stern through the wind. During a gybe, the wind crosses over...

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  • General Nautical Terminology Gybe-oh!The call to indicate that the helm is being put across to gybe

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