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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 & SeamanshipA great introduction to navigation and basic seamanship.
    • Day Skipper TheoryMany of the best skippers started their journey here.
    • Coastal Skipper / Yachtmaster® TheoryComing SoonEssential preparation for the Yachtmaster® practical exam.
    • SRC (VHF) Marine Radio CourseAn essential course for anyone intending to use a marine radio.
  • 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 nauctical, including marinas u0026 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 u0026 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 & SeamanshipA great introduction to navigation and basic seamanship.
    • Day Skipper TheoryMany of the best skippers started their journey here.
    • Coastal Skipper / Yachtmaster® TheoryComing SoonEssential preparation for the Yachtmaster® practical exam.
    • SRC (VHF) Marine Radio CourseAn essential course for anyone intending to use a marine radio.
  • 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 nauctical, including marinas u0026 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 u0026 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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Glossary

AJAX progress indicator
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: 1071
  • Term
    Definition
  • 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...

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  • 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...

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  • 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...

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  • 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...

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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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  • General Nautical Terminology Not Under CommandVessel broken down. No steerage, engines defunct etc.
  • Phonetic Alphabet, Signals & Communication November

    Pronounced: no-VEM-ber

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

  • 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...

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  • Abbreviation, Light Characteristic Oc

    A light with more light than dark (is on for longer than it is off).

    Occulting refers to a type of navigational light in which the light is...

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  • Abbreviation, Light Characteristic Occulting (Oc)

    A light with more light than dark (is on for longer than it is off).

    Occulting refers to a type of navigational light in which the light is...

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  • General Nautical Terminology Ocean Data Acquisition System (ODAS)

    The Ocean Data Acquisition System (ODAS) is a system used to collect, process, and transmit various types of oceanographic data. This system...

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  • Flag / Pennant, Signals & Communication Code Flag Oscar (O)

    The International Maritime Signal Flag Oscar.

    Meaning

    Man overboard. (Often attached to the Danbuoy pole on boats.)
    The semaphore flag.

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