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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 RaftTwo or more vessels tied up alongside each other
  • General Nautical Terminology, Navigation Range of Tide

    The vertical difference between the high tide and the succeeding low tide in a specific tidal cycle.

    The range of tide is a fundamental...

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  • General Nautical Terminology Raster chartElectronic chart which is a direct copy of a paper chart with limited zooming capability
  • General Nautical Terminology, Navigation Rate (Tidal Stream)

    The speed at which a tidal stream flows, typically measured in knots.

    The rate of a tidal stream is the velocity at which the water moves due...

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  • Flag / Pennant, Signals & Communication Code Flag Romeo (R)

    The International Maritime Signal Flag Romeo.

    Meaning

    Distance (range) in nautical miles. Given using Numeral Pennants.

  • General Nautical Terminology Reach

    The point of sail where the wind is coming from the side of the boat, roughly perpendicular to the direction the boat is travelling. 

    A reach...

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  • General Nautical Terminology ReachingSailing across the wind: from about 60° to about 160° off the wind. Reaching consists of "close reaching" (about 60° to 80°), "beam reaching"... More Details
  • General Nautical Terminology Ready AboutThe helmsman’s shout that he intends to go about shortly
  • Flag Semaphore Ready (Flag Semaphore)

    The Ready (Flag Semaphore) signal shows the sender is ready to send a message. The same shape is also used for Space (Flag Semaphore) & Rest...

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  • Flag Semaphore Ready to Recieve (Flag Semaphore)

    The Ready to Recieve signal shows the sender that the recipient is ready to receive a message. This shape is displayed once the sender has...

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  • General Nautical Terminology Reef

    A reef is a submerged ridge of rock, coral, or sand near the surface of oceans or seas. It can be made up of living organisms like coral or...

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  • General Nautical Terminology Reefing

    Verb: Reefing refers to the act of reducing the area of a sail to decrease wind exposure and maintain control in strong winds.

    Noun: Reefing...

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  • General Nautical Terminology Reefing Hook

    A reefing hook is located near the bottom of the mast at the gooseneck, where the boom connects to the mast. When reefing, the cringle is placed...

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  • General Nautical Terminology Reefing LinesReefing lines are used to reduce the size of the mainsail. By reducing the size of the mainsail we can improve the yacht's stability and... More Details
  • Flag Semaphore Rest (Flag Semaphore)
    Rest (Flag Semaphore)

    When the sender is not actively sending messages, both flags are held by their side. The same shape is also used for Space (Flag Semaphore) &...

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  • General Nautical Terminology Restricted in Ability to ManoeuvreUnable to get out of the way due to work being done. Could be a dredger, towing vessel etc.
  • General Nautical Terminology Restricted VisibilityVisibility restricted by rain, drizzle, fog, etc., during which vessels are required to proceed at a safe speed and to navigate with extreme caution
  • General Nautical Terminology Rhumb LineA line on the surface of the earth that cuts all meridians at the same angle.  On a standard Mercator chart the rhumb line appears as a straight line
  • General Nautical Terminology Riding TurnOn a winch the situation where an earlier turn rides over a later turn and jams
  • General Nautical Terminology Rigging

    The system of ropes, cables, chains, and other apparatus used to support and control the sails and masts of a sailing vessel.

    Rigging is...

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