Glossary Archive

A Cutlass bearing is a water-lubricated bearing used in marine applications to support rotating shafts, such as propeller shafts. It is self-aligning and typically made of rubber or a composite material. Cutless bearings reduce friction and wear on the shaft, allowing it to rotate smoothly and efficiently. They are commonly used in boats and ships...

A cyclone is a large-scale atmospheric circulation system characterised by inward-spiralling winds around a low-pressure centre. In marine terminology, a cyclone is often called a tropical cyclone or hurricane when it occurs over warm ocean waters and is accompanied by thunderstorms and heavy rainfall. Cyclones can produce high winds, storm surges, and intense precipitation, posing...

Cyclonic refers to a weather system characterised by air rotation around a low-pressure centre, typically in a counterclockwise direction in the Northern Hemisphere and a clockwise direction in the Southern Hemisphere. Cyclonic systems can produce strong winds, heavy rainfall, and sometimes severe weather, such as thunderstorms or tornadoes. Cyclonic storms include hurricanes, typhoons, and tropical...

A floating marker pole, often equipped with a flag, light, or buoyancy aid, used in maritime settings to indicate a specific location, such as a man-overboard position or a fishing net. A danbuoy is a vital piece of equipment in marine operations, designed to serve as a highly visible marker on the water. It typically...

A lightweight, high-holding-power anchor with two wide, pivoting flukes designed to dig into sand or mud for secure holding.  The Danforth anchor, also known as a fluke anchor, is a popular choice for small to medium-sized boats due to its lightweight design and strong holding power in soft seabeds such as sand or mud. It...

A crane, often working in pairs and usually made of steel, used to lower things over the side of a ship, including launching a lifeboat over the side of a ship. Sometimes seen on yachts for carrying the tender

Crane-like structures mounted on a vessel used for lowering, raising, and storing lifeboats, tenders, or other equipment.  Davits are essential components on ships and boats, primarily designed for handling lifeboats and small auxiliary craft. They consist of a pair of arms, often curved or angled, that extend outward from the vessel’s structure. These arms are...

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 want more information about Day Shapes, you can look at Vessel Identification (by day) in the Rules of the road module.

The RYA Day Skipper Practical (Motor) course equips participants to take charge of motor cruisers during short passages. Over five days, participants practice navigation, boat handling, and emergency procedures under the guidance of an instructor. The course emphasizes planning, safety, and decision-making, preparing participants to skipper motorboats confidently in familiar waters.

The RYA Day Skipper Practical (Sail) course teaches participants to skipper a yacht during short coastal passages. This five-day course covers navigation, pilotage, and boat handling, with a strong emphasis on safety and planning. Participants practice anchoring, mooring, and responding to emergencies under the guidance of an instructor. By the end, they will be ready...