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, 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.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.
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 & TerminologyUnderstanding 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 FlashcardsFlashcards 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 BlogFrom 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.Understanding the language of the marine world is like trying to learn a pirate’s secret code while juggling fish. You’ll wonder why a “sheet” isn’t something you sleep under but a rope that controls a sail. “Bowsprit” sounds like a sneeze, “booby hatch” isn’t a bird’s hideout, and “port” doesn’t come in a glass—it’s just left. If someone yells, “Man overboard!” don’t ask which direction they swam. And heaven help you if you think “scuttlebutt” is gossip—well, actually, you’d be right about that one. By the time you’ve figured out that “head” means toilet and “galley” isn’t an alley with gourds, you’ve already been hit with a wave and lost your hat to the wind they call a “nor’easter.”
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.
An internationally standardised system of flags, radiotelephony and coded signals for communicating important maritime messages, particularly about safety and navigation. The code assigns meanings to single-letter flags, multi-flag groups, numeral pennants and selected spoken or Morse forms so vessels and shore stations can exchange concise messages across language barriers. Medical and distress-related sections support specialised…
A dimensionless GNSS geometry factor combining horizontal and vertical dilution of precision for three-dimensional position. PDOP reflects how the spatial arrangement of the satellites used amplifies common ranging errors into the latitude, longitude and height solution. Lower values generally indicate more favourable geometry, and mathematically PDOP combines HDOP and VDOP by root-sum-square. It does not…
A dimensionless GNSS geometry factor for amplification of ranging errors into the horizontal position solution. HDOP reflects the east-west and north-south geometry of the satellites used. Lower values generally indicate that common ranging errors will produce a smaller horizontal position uncertainty, while clustered azimuths produce weaker geometry. HDOP is not horizontal accuracy by itself and…
A dimensionless GNSS geometry factor describing how ranging errors are amplified in the vertical component of a position fix. VDOP depends on the distribution of the satellites used in the solution. Because satellites are normally visible above rather than below the receiver, vertical geometry is often weaker than horizontal geometry and altitude uncertainty may be…
A dimensionless GNSS geometry factor describing how ranging errors are amplified in the receiver-clock estimate. A GNSS receiver solves for its clock offset as well as position because its clock is not synchronised as precisely as the satellites’ atomic clocks. TDOP expresses the geometric contribution to uncertainty in that time solution. Lower TDOP generally indicates…
A dimensionless GNSS geometry factor combining three-dimensional position and receiver-clock uncertainty. GDOP reflects how the relative positions of the satellites used in a solution amplify common ranging errors across latitude, longitude, height and time. It combines position dilution of precision and time dilution of precision, commonly by a root-sum-square relationship. Low GDOP indicates favourable satellite…
A standard set of code words used to transmit letters clearly when speech may be misunderstood. In marine radiotelephony, letters are spoken as words such as Alfa, Bravo, Charlie and Delta. The system reduces confusion between similar-sounding letters when spelling vessel names, call signs, coordinates and other important information over a noisy or weak radio…
An expression meaning to feel ill, unwell or below one’s usual condition. The phrase is frequently claimed to have a nautical origin, sometimes linked to sick sailors sheltering below deck from severe weather. That explanation is popular but not securely documented, so it is better treated as an uncertain origin rather than established maritime history….
A buoy, platform or other installation that gathers and often transmits oceanographic or meteorological observations.
An unmanned, self-propelled submersible that carries out a programmed mission without a continuous control link. An AUV uses onboard navigation, sensors, power and control systems to survey or inspect beneath the surface. Typical work includes hydrographic mapping, scientific sampling, pipeline and cable inspection, mine countermeasures and search operations. Unlike a remotely operated vehicle, an AUV…
If you belive the Earth is flat, you're about to fall of the end...
If you belive the Earth is flat, you're about to fall of the end...
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