Glossary Archive

An aperture on the hull of a vessel that admits light and, sometimes, air

Sea area of the Met Office Shipping Forecast. Located off the south coast of England, near Portland Bill in Dorset. Named for Portland Bill on Dorset’s coast, Portland has west to southwest winds of Force 4–6 and moderate seas, occasionally rough in winter. Strong currents around the Bill expose historic wrecks, making it a popular...

A navigational tool used in marine chartwork to measure and plot courses, bearings, and distances on nautical charts. The Portland Plotter is an essential instrument in the toolkit of any navigator, particularly in traditional maritime navigation. It is a flat, rectangular piece of transparent plastic, typically marked with a compass rose, parallel lines, and a...

The port listed in a vessel’s registration documents and lettered on her stern

The aft-left section of a vessel when facing forward, located between the port beam and the stern. The term "port quarter" is a specific navigational reference used to describe a particular area of a vessel. In maritime terminology, the vessel is divided into sections to aid in communication and orientation. "Port" refers to the left-hand...

The situation in sailing where the wind is coming over the port (left) side of the vessel, and the boom is positioned on the starboard (right) side. Port Tack is a fundamental concept in sailing that describes the orientation of a vessel relative to the wind. When a sailboat is on a port tack, the...

Measurement of the geometric strength of satellite configuration in a Global Navigation Satellite System (GNSS) receiver. It quantifies the effect of satellite geometry on the accuracy of the position calculation. A lower PDOP value indicates better satellite geometry and results in more accurate position fixes. PDOP is calculated based on the positions of the satellites...

The RYA Powerboat Advanced course is designed for experienced powerboaters operating in challenging conditions, including night navigation. Participants learn advanced passage planning, navigation, and high-speed handling in adverse weather. The course emphasizes safety, decision-making, and the use of radar and electronic aids. By the end, participants will have the confidence to operate powerboats independently in...

The RYA Powerboat Intermediate course bridges the gap between Level 2 and advanced powerboating. Participants learn navigation, passage planning, and handling powerboats in moderate conditions. The course includes practical exercises on anchoring, docking, and responding to emergencies. This program is ideal for those seeking to improve their skills and prepare for more challenging boating environments...

The official permission granted to a vessel by port health authorities, allowing it to enter a port and conduct operations after confirming it is free from contagious diseases or other health risks. Pratique is a term deeply rooted in maritime operations, particularly concerning the health and safety protocols of ports and harbours. Historically, it emerged...