Glossary Archive

Beaufort Scale - Force 12 (Hurricane Force 12) Hurricane-force is a term used to describe wind speeds equal to or greater than 64 knots (74 miles or 119 kilometres per hour), the minimum wind speed threshold for a storm to be classified as a hurricane. Winds of this magnitude are capable of causing significant damage...

A lifting surface or structure mounted beneath a vessel's hull that, when moving through water, generates lift to raise the hull above the waterline, reducing drag and increasing speed. A hydrofoil is a specialised marine technology designed to improve the efficiency and performance of watercraft. The hydrofoil itself is a wing-like structure, often made of...

The surveying and description of seas, coasts, seabeds and navigable waters. This work provides the measurements and information used to produce nautical charts, pilot books and other navigation publications. It includes depths, seabed features, coastline shape, tides, currents, hazards and aids to navigation. Accurate surveys allow mariners to plan routes, identify dangers and understand the...

A non-governmental organisation that develops standards and best practices for the safety and efficiency of maritime navigation through the use of aids to navigation. The International Association of Lighthouse Authorities (IALA), established in 1957, plays a crucial role in ensuring the safety of global maritime navigation. Its primary mission is to harmonise the worldwide use...

An official document that certifies a person's ability to operate a pleasure craft in countries that recognise it.  The International Certificate of Competence (ICC) is a standardised qualification that demonstrates a boater's competency to operate a pleasure craft in international waters where it is recognised. It is issued by authorised national authorities and is often...

The International Maritime Signal Flag India. Meaning I am altering course to port.

A numerical weather prediction model that uses a grid system based on an icosahedron to simulate atmospheric processes with high resolution and accuracy.  The ICOsahedral Nonhydrostatic model, often abbreviated as ICON, is a cutting-edge numerical weather prediction model used by meteorologists to forecast weather patterns with high precision. This model utilises a unique grid system...

A numerical weather prediction model that uses a grid system based on an icosahedron to simulate atmospheric processes with high resolution and accuracy.  The ICOsahedral Nonhydrostatic model, often abbreviated as ICON, is a cutting-edge numerical weather prediction model used by meteorologists to forecast weather patterns with high precision. This model utilises a unique grid system...

A system of flags, codes, and symbols used by ships to communicate essential messages and ensure safety at sea, regardless of language barriers. The International Code of Signals (ICS) is a globally recognised communication system designed to facilitate clear and unambiguous exchanges between vessels and between ships and shore stations. Established in the early 19th...

An imaginary longitudinal line located at approximately 180 degrees longitude serving as the demarcation where the calendar date changes by one day when crossed. The International Date Line (IDL) is a conceptual boundary on the Earth's surface, primarily situated along the 180th meridian in the mid-Pacific Ocean. It is not a straight line but zigzags...