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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!
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        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

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: 143
  • Term
    Definition
  • Flag Semaphore, Signals & Communication Letter S (Flag Semaphore)
    Flag semaphore indicating the letter S.

    Flag semaphore indicating the letter S.

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

    International Morse Code sequence representing the letter S.

  • General Nautical Terminology SlideA metal or plastic fitting on the luff or foot of a sail running in a track on the mast or boom
  • General Nautical Terminology Slip Lines

    Ropes or lines used to temporarily secure a vessel to a dock or mooring point in such a way that they can be released from onboard without...

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  • General Nautical Terminology Slipped Lines

    The act of releasing a vessel's mooring lines in a controlled manner, allowing it to depart from a berth or dock without assistance from shore...

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  • General Nautical Terminology Slipway

    A sloped structure or ramp leading into the water, used for launching, retrieving, or repairing boats and ships. 

    A slipway, also known as a...

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  • General Nautical Terminology SloopA small to mid-sized sailboat larger than a dinghy, with one mast bearing a main sail and head sail.
  • General Nautical Terminology SlotGap between two sails.
  • General Nautical Terminology, Navigation Small Vessel Electronic Chart Systems (SV-ECS)

    Electronic navigation standards for commercial vessels less than 24m .

    Equipment meeting the requirements of this performance standard is...

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  • General Nautical Terminology, Signals & Communication SMCP

    A set of internationally agreed-upon phrases used to ensure clear, concise, and unambiguous communication at sea, particularly between vessels...

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  • General Nautical Terminology SnatchJerk caused by too short an anchor cable in a seaway; To take a turn quickly around a cleat, bollard or Samson post
  • General Nautical Terminology Snug DownTo prepare for heavy weather by securing all loose gear
  • General Nautical Terminology, Navigation SOG

    The actual velocity of a vessel relative to the Earth's surface, accounting for the effects of currents, tides, and other environmental...

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  • General Nautical Terminology SOLAS

    An international maritime treaty that sets minimum safety standards for ship construction, equipment, and operation. Its primary goal is to...

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  • General Nautical Terminology, Safety SOLAS V

    Chapter V of SOLAS (Safety of life at Sea) refers to the Safety of Navigation for all vessels at sea.

    SOLAS V for pleasure craft

    SOLAS V...

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  • General Nautical Terminology Sole

    Sea area of the Met Office Shipping Forecast. Covers Sole Bank in the eastern Bay of Biscay off the French coast.

    From the Sole Bank, famed...

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  • General Nautical Terminology, Parts of a Boat Sole boards

    The flat, horizontal planks or panels that form the flooring of a boat's interior, typically installed over the bilge area to provide a stable...

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  • General Nautical Terminology, Morse Code, Safety, Signals & Communication SOS

    The universally recognised distress signal used in maritime communication to indicate an emergency requiring immediate assistance.

    The German...

    More Details
  • General Nautical Terminology SoundTo measure the depth of water
  • General Nautical Terminology SoundingThe depth of water below chart datum
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