Glossary

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...

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...

The act of reducing the area of a sail to decrease wind exposure and maintain control in strong winds.

Reefing is an essential technique in...

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...

Ropes or cords used to reduce the sail area by securing a portion of the sail to the boom or mast, thereby making the vessel more manageable in...

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) &...

A ship that, due to the nature of its work, is unable to keep out of the way of other vessels as required by the International Regulations for...

Conditions in which a vessel's ability to see is significantly reduced due to environmental factors such as fog, heavy rain, snow, or...

A loop of rope that crosses over itself on a winch drum or cleat, often causing friction or jamming.

A riding turn is a term commonly used in...

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

Rigging is...

Verb - The process of setting up and adjusting the sails, lines, and other necessary equipment on a boat or ship to ensure it is ready for...

An internationally renowned professional institution representing naval architects and marine engineers worldwide. It was founded in 1860 and is...

The possibility that a collision may occur, usually established by taking a compass bearing of an approaching vessel. Defined in Rule 7 - Risk of...

Flag semaphore indicating the letter R.

International Morse Code sequence representing the letter R.

The volunteer crewed rescue service providing 24-hour rescue services around the UK and Irish coastline. They also provide seasonal lifeguards...

Sea area of the Met Office Shipping Forecast. Spans the North Atlantic west of Ireland around Rockall islet.

Named for the remote granite islet...

The line, chain, or cable that connects an anchor to a vessel.

Rode refers to the length of chain, rope, or a combination of both that...

Roller furling is used on sailing boats to roll or unroll a sail, typically the jib or genoa, around a stay to quickly deploy or stow the...

A roller reef is a method of reducing sail area on a sailboat by partially rolling or furling the sail around the boom or the headstay. This...

Pronounced: ROW-me-oh

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

A spare fender, held ready by a crew member in case of emergencies.

A roving fender is a type of fender used on boats and ships to protect the...

The volunteer crewed rescue service providing 24-hour rescue services around the UK and Irish coastline. They also provide seasonal lifeguards...

The national governing body for sailing, motorboating, and other recreational boating activities in the United Kingdom. 

The Royal Yachting...

A rudder is a flat, movable surface attached to the stern of a boat or ship. It is used to steer the vessel by redirecting water flow.

The...

To allow a line, rope, or cable to move freely through a block, fairlead, or other fitting.

The direction a vessel is moving, particularly...

The act of sailing a boat downwind, with the wind coming from astern. 

Running is one of the main points of sail, where a vessel moves with...

A rigging component on a sailboat that helps support the mast. It runs from each lateral corner of the stern to the mast at the level where the...

The ropes, lines, and cables that control a sailing vessel’s sails and other movable components.

Running rigging is a critical part of a...

The national governing body for sailing, motorboating, and other recreational boating activities in the United Kingdom. 

The Royal Yachting...

A lightweight Plotter, suitable for use in a classroom for navigation exercises.

This handy size plotter has been specifically designed to...

Publication compiled to support RYA Theory courses. The RYA Training Almanac contains exerts that mimic Nautical Almanacs in the real world.

A specialised, non-navigational chart produced by the Royal Yachting Association (RYA) for teaching and practising navigation and chartwork...

An international standard developed by the International Hydrographic Organization (IHO) for the management, exchange, and interoperability of...

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

The Saffir-Simpson Scale is a classification system that categorises hurricanes based on their wind speed and potential for damage. It ranges...

A sail drive is a transmission system for a boat whose inboard engine has a horizontal output shaft. The sail drive's input shaft is, therefore,...

Sailing directions, also known as nautical directions or pilots, are publications that provide detailed information for navigating coastal and...

A designated storage space aboard a vessel where sails and related equipment are kept when not in use.

A sail locker is an essential feature...

The concentration of dissolved salts in water, typically measured in parts per thousand (ppt) or practical salinity units (PSU).

Salinity is a...

The coordinated efforts undertaken to locate and assist individuals in distress or imminent danger, typically at sea, and to bring them to...

An emergency device that responds to radar signals by transmitting a series of pulses to help rescuers locate a vessel or liferaft in...

A German boating licence required for operating recreational motorboats and sailing vessels above certain power or length limits in German...

A German boating licence required for operating recreational motorboats and sailing vessels on inland waterways. 

The Sportbootführerschein...

A German boating licence required for operating recreational motorboats and sailing vessels with an engine of more than 15 horsepower in coastal...

The International Maritime Signal Flag Sierra.

Meaning

I am operating astern propulsion.
If appended with a Numeral Pennant, Speed...

An opening in the side of a ship or boat, designed to allow water on deck to drain overboard.

In maritime terminology, a scupper is an...

A device, typically a canvas or synthetic fabric drogue, deployed in the water to stabilise a vessel by creating drag and reducing drift in rough...

A cooling wind that blows from the sea towards the land, typically occurring during the daytime due to temperature differences between the land...

The ability of a person to maintain balance and move steadily on a vessel in motion, particularly in rough seas.

Sealegs is a term deeply...

The coordinated efforts undertaken to locate and assist individuals in distress or imminent danger, typically at sea, and to bring them to...

An emergency device that responds to radar signals by transmitting a series of pulses to help rescuers locate a vessel or liferaft in...

A location where tidal information is derived by applying corrections to data from a nearby Standard Port. 

A secondary port is a coastal...

Substitute or repeater flags allow messages with duplicate characters to be signalled without requiring multiple sets of flags.

Occasionally a light may not be visible through 360 degrees, or it may shine different colours depending on where it is viewed from. In this...

A maritime safety message broadcast over radio to convey important but non-urgent navigational or weather-related information.

Sécurité is a...

A signalling system used to convey information at a distance by means of visual signals, typically using flags or lights.

Semaphore is a...

A type of boat or ship designed to operate efficiently in both displacement and planing modes, offering a balance between speed and fuel...

The direction which a current flows in a body of water.

In marine navigation, understanding the set of a current is crucial for plotting an...

The process of securing a boat in a stationary position by deploying and embedding an anchor into the seabed.

When a mariner 'sets anchor',...

To "set sail" means to begin a voyage or journey by sea, typically by hoisting the sails of a sailboat or ship to catch the wind and propel the...

A U-shaped metal fitting with a pin or bolt across the opening, used in marine applications to connect ropes, chains, or other fittings...

Shaft drive refers to a method of transferring power from an engine to a boat's propeller. In this system, a driveshaft connects the engine to...

The part of an anchor that digs into the seabed to secure the boat in place. 

The Shank refers to the long, vertical part of an anchor that...

Sea area of the Met Office Shipping Forecast. Lies off the west coast of Ireland at the mouth of the River Shannon.

From the Shannon Estuary...

A line or rope used to control the angle of a sail relative to the wind.

In sailing, a sheet is an essential part of the rigging system and...

A maritime weather broadcast provided by the UK Met Office, offering vital information on sea conditions, wind, and visibility for seafarers in...

A designated route in a body of water that is regularly used by commercial and cargo vessels to ensure safe and efficient maritime...

To reduce the amount of sail area exposed to the wind, typically to maintain control and safety in strong winds.

Shortening sail is a sailing...

A strong, fixed line or wire that supports a sailing vessel's mast laterally, running from the mast to the sides of the hull or to...

Pronounced: see-AIR-rah

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

A skeg is a small fin or projection on the bottom of a boat's hull, typically near the stern. It helps to provide directional stability and...