Glossary Archive

The Challenger of Record is the yacht club or team officially representing the first challenging team in a sailing competition, such as the America's Cup. The Challenger of Record works closely with the defender (the current titleholder) to organise the event, negotiate the rules, and ensure fair competition. They play a crucial role in shaping...

An internationally renowned professional institution representing naval architects and marine engineers worldwide. It was founded in 1860 and is based in London, United Kingdom. RINA provides professional accreditation, training, and technical support to individuals and organisations involved in the design, construction, and operation of ships and marine structures. The institution plays a key role in...

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

The phrase “three sheets to the wind” comes straight from nautical life—and originally had nothing to do with drinking at all! 🚢 Nautical Origin: In sailing, a “sheet” is not a sail—it’s a rope (or line) used to control a sail’s angle to the wind. If a sailboat had one sheet loose, it would flap a bit. With two, it would...

The horizontal movement of water caused by the rise and fall of the tide. A tidal stream refers to the flow of water generated by the gravitational pull of the moon and the sun, which causes the sea level to rise and fall in a cyclical manner. This movement of water is distinct from ocean...

A collection of charts that depict the set (direction) and rate (speed) of tidal currents at various stages of the tidal cycle. A Tidal Stream Atlas is an essential navigational tool used by mariners to understand the movement of water caused by tides in a specific area. These atlases provide detailed information about the direction...

The rise and fall of sea levels caused by the gravitational forces of the moon and the sun acting on the Earth's oceans. Tides are characterised by regular and predictable patterns, with two high tides and two low tides occurring approximately every 24 hours and 50 minutes. Tides are crucial in marine ecosystems, navigation, and...

Charts or listings that provide the predicted times and heights of high and low tides for specific coastal locations over a given period. Tide tables are essential tools for mariners, fishermen, and anyone involved in coastal activities, as they offer crucial information about the timing and magnitude of tidal changes. These tables are typically presented...

A lever attached to the rudder head by which the helmsman moves the rudder

A measure used in satellite navigation systems, such as GPS, to quantify the effect of errors in the timing of satellite signals on the accuracy of position calculations. It represents how much the timing errors in the satellite signals dilute the overall precision of the position solution. A lower TDOP value indicates better timing accuracy...