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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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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.
  • Chandlery
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!
ALL0-9ABCDEFGHIJKLMNOPQRSTUVWXYZ
Results: 33
  • Term
    Definition
  • General Nautical Terminology National Oceanic and Atmospheric Administration (NOAA)

    The National Oceanic and Atmospheric Administration is an American scientific agency within the United States Department of Commerce that focuses...

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  • Organisation NATO

    An intergovernmental military alliance established in 1949 aimed to ensure the collective defence of its member state through political and...

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  • General Nautical Terminology Nautical Almanac

    A comprehensive publication containing astronomical data and navigational information essential for maritime navigation.

    A Nautical Almanac is...

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  • General Nautical Terminology, Navigation Nautical Mile

    A nautical mile is a unit of measurement used in maritime navigation that is equivalent to one minute of latitude or approximately 1.852...

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  • General Nautical Terminology, Navigation Navigational Telex (NAVTEX)

    A maritime communication system used for the automatic broadcast of navigational and meteorological warnings, forecasts, and urgent safety...

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  • General Nautical Terminology Navigation Lights

    A system of coloured and white lights displayed on a vessel to indicate its position, heading, and status to other vessels, especially during low...

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  • General Nautical Terminology, Navigation NAVTEX

    A maritime communication system used for the automatic broadcast of navigational and meteorological warnings, forecasts, and urgent safety...

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  • Flag / Pennant, Signals & Communication Code Flag November (N)

    The International Maritime Signal Flag November.

    Meaning

    Negative.

  • General Nautical Terminology NDB

    A radio transmitter at a fixed location that emits signals in all directions, used in marine navigation to help vessels determine their position...

    More Details
  • General Nautical Terminology Neap RangeThe difference in height between HW and LW on a Mean (average) neap tide.
  • General Nautical Terminology, Navigation Neap Tide

    When the difference between high and low water is at its smallest, typically occurring twice a month during the first and third quarters of the...

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  • Weather (Meteorology) Near Gale

    Sometimes used to describe wind strength approaching a Gale.

  • Organisation NLB

    The Northern Lighthouse Board is a maritime organisation responsible for maintaining lighthouses and navigation aids in Scotland and the Isle of...

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  • Flag Semaphore, Signals & Communication Letter N (Flag Semaphore)
    Flag semaphore indicating the letter N.

    Flag semaphore indicating the letter N.

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

    International Morse Code sequence representing the letter N.

  • General Nautical Terminology, Navigation NM

    A Notice to Mariners is an official publication issued by maritime authorities to provide important information and updates regarding...

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  • General Nautical Terminology NOAA

    The National Oceanic and Atmospheric Administration is an American scientific agency within the United States Department of Commerce that focuses...

    More Details
  • General Nautical Terminology Non-Directional Beacon (NDB)

    A radio transmitter at a fixed location that emits signals in all directions, used in marine navigation to help vessels determine their position...

    More Details
  • Organisation North Atlantic Treaty Organization (NATO)

    An intergovernmental military alliance established in 1949 aimed to ensure the collective defence of its member state through political and...

    More Details
  • Organisation Northern Lighthouse Board (NLB)

    The Northern Lighthouse Board is a maritime organisation responsible for maintaining lighthouses and navigation aids in Scotland and the Isle of...

    More Details
  • General Nautical Terminology, Weather (Meteorology) North Utsire

    Sea area of the Met Office Shipping Forecast. Located in the northern North Sea, adjacent to Utsira Island off the west coast of Norway.

    Derived...

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  • General Nautical Terminology, Navigation Notice to Mariners (NM)

    A Notice to Mariners is an official publication issued by maritime authorities to provide important information and updates regarding...

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  • Abbreviation, General Nautical Terminology Not Under Command (NUC)

    A ship that, due to exceptional circumstances, is unable to manoeuvre as required by the International Regulations for Preventing Collisions at...

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  • Phonetic Alphabet, Signals & Communication November

    Pronounced: no-VEM-ber

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

  • Abbreviation, General Nautical Terminology NUC

    A ship that, due to exceptional circumstances, is unable to manoeuvre as required by the International Regulations for Preventing Collisions at...

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  • Flag / Pennant, Signals & Communication Numeral 4 (Flag Pennant)

    The flag represents the numerical value of four.

  • Flag / Pennant, Signals & Communication Numeral 5 (Flag Pennant)

    The flag represents the numerical value of five.

  • Flag / Pennant, Signals & Communication Numeral 6 (Flag Pennant)

    The flag represents the numerical value of six.

  • Flag / Pennant, Signals & Communication Numeral 7 (Flag Pennant)

    The flag represents the numerical value of seven.

  • Flag / Pennant, Signals & Communication Numeral 8 (Flag Pennant)

    The flag represents the numerical value of eight.

  • Flag / Pennant, Signals & Communication Numeral 9 (Flag Pennant)

    The flag represents the numerical value of nine.

  • Flag / Pennant, General Nautical Terminology, Signals & Communication Numeral Pennant

    A triangular flag used in maritime signalling to represent numerical digits, typically in conjunction with other signal flags.

    A numeral...

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  • Flag Semaphore, Signals & Communication Numerals-Numbers Follow (Flag Semaphore)

    This flag semaphore signal indicates a change from letters to numbers (Numbers Follow), indicating that the signaller will be using the...

    More Details

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