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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.
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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: 1149
  • Term
    Definition
  • General Nautical Terminology, Navigation Current

    The continuous, directed movement of seawater or other bodies of water caused by various factors such as wind, tides, and differences in water...

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  • General Nautical Terminology, Weather (Meteorology) Cyclone

    A cyclone is a large-scale atmospheric circulation system characterised by inward-spiralling winds around a low-pressure centre. In marine...

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  • General Nautical Terminology, Weather (Meteorology) Cyclonic

    A weather system characterised by rotating winds around a low-pressure centre, often associated with stormy conditions at sea.

    Cyclonic...

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  • General Nautical Terminology, Safety Danbuoy

    A floating marker pole, often equipped with a flag, light, or buoyancy aid, used in maritime settings to indicate a specific location, such...

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  • General Nautical Terminology Danforth Anchor

    A lightweight, high-holding-power anchor with two wide, pivoting flukes designed to dig into sand or mud for secure holding. 

    The Danforth...

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  • General Nautical Terminology Davit

    Crane-like structures mounted on a vessel used for lowering, raising, and storing lifeboats, tenders, or other equipment. 

    Davits are...

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  • General Nautical Terminology Day Shape

    A ball, cone or diamond-shaped object, ordinarily black, hoisted by day on a vessel to indicate a particular status within the IRPCS. 

    If you...

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  • Courses, RYA Day Skipper Practical (Motor)The RYA Day Skipper Practical (Motor) course equips participants to take charge of motor cruisers during short passages. Over five days,... More Details
  • Courses, RYA Day Skipper Practical (Sail)

    The RYA Day Skipper Practical (Sail) course teaches participants to skipper a yacht during short coastal passages. This five-day course covers...

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  • Courses, RYA Day Skipper TheoryThe RYA Day Skipper Theory course provides aspiring skippers with the knowledge to navigate safely in coastal waters. This comprehensive program... More Details
  • Flag / Pennant, Signals & Communication Code Flag Delta (D)

    The International Maritime Signal Flag Delta.

    Meaning

    I am manoeuvring with difficulty.
    If appended with a Numeral Pennant, a Date.

  • General Nautical Terminology, Navigation Dead Reckoning (DR)

    A navigational method used to estimate a vessel's current position based on a previously known position, factoring in speed, time, and course...

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  • General Nautical Terminology Deck Officer

    A licensed mariner responsible for the safe navigation, operation, and management of a vessel's deck department.

    Deck Officers, also known as...

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  • Phonetic Alphabet, Signals & Communication Delta

    Pronounced: DEL-ta

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

  • General Nautical Terminology Delta

    A triangular-shaped area of sediment deposited at the mouth of a river, where it meets a body of water such as a sea or ocean.

    A delta refers...

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  • General Nautical Terminology Delta Anchor

    A plough-style anchor with a triangular, streamlined shape, designed for strong holding power in various seabeds, especially sand and mud.

    More Details
  • General Nautical Terminology Depression

    A depression is an area of low atmospheric pressure characterised by inward-spiraling winds. Depressions are often associated with stormy weather...

    More Details
  • General Nautical Terminology DepthAn electronic depth-finding instrument or the amount of water at a given time
  • General Nautical Terminology, Navigation Deviation

    The difference between a vessel's actual compass heading and the magnetic heading indicated by the compass.

    Deviation is caused by the...

    More Details
  • General Nautical Terminology, Navigation Deviation card

    A reference chart used on a vessel to indicate the compass error caused by local magnetic influences, showing the necessary corrections for...

    More Details
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