Glossary Archive

A specialised agency of the United Nations headquartered in London and responsible for regulating shipping, the IMO has 175 Member States. The IMO is responsible for improving the safety and security of international shipping and preventing pollution from ships. It is also involved in legal matters, including liability and compensation issues and the facilitation of...

An impeller is a rotating component within a pump or compressor that is used to impart motion to a fluid. It typically consists of blades or vanes that are mounted on a central shaft and is designed to create flow and pressure within the fluid being pumped. In marine applications, impellers are commonly found in...

The RYA Improve Your Wingsurfing course is aimed at wingsurfers who want to refine their skills and gain more control. Participants learn advanced steering, upwind sailing, and techniques for handling stronger winds. The course also focuses on safety, efficiency, and optimizing equipment. By the end, wingsurfers will feel confident tackling a broader range of conditions...

Pronounced: IN-dee-ah The term for the letter I in the NATO Phonetic Alphabet.

A line or tackle used to pull a sail or spar inboard, typically to adjust sail shape or reduce projection beyond the hull. An in hauler is a control line or system used aboard sailing vessels to draw a sail, usually a headsail such as a jib or genoa, closer to the centreline of the...

A situation where a sailing vessel is stalled with its bow pointed directly into the wind, making it difficult to manoeuvre or gain forward momentum. When a sailing vessel is "in irons," it finds itself in a position where the bow is directly facing into the wind, and the sails are unable to catch any...

The RYA Inland Waterways Crew course provides essential training for assisting with operations on canals, rivers, and other inland waterways. Participants learn line handling, lock navigation, and basic safety procedures. The course emphasizes teamwork and practical skills needed to support the helmsperson effectively. By the end, participants will feel confident contributing as crew members on...

The RYA Inland Waterways Helmsman’s course is designed for those operating boats on canals and rivers. This two-day course covers boat handling, mooring, and lock operation. Participants also learn essential safety procedures and how to navigate in narrow or confined waterways. By the end, participants will have the skills and confidence to helm inland waterway...

A global satellite communications organisation providing maritime, aviation, and land-based services for safety and operational connectivity.  INMARSAT (International Maritime Satellite Organisation) was established to improve maritime communications, particularly for distress and safety at sea. It operates a network of geostationary satellites that provide reliable voice and data services across the world's oceans. The system is...

The area of water close to the shore, typically within a few miles, where vessels operate in relatively calmer and shallower waters compared to offshore regions. Inshore, in a maritime context, generally describes the zone of water that is near the coastline, often extending up to a few nautical miles from land. This area is...