Glossary Archive

A graphical representation of meteorological data over a specific area at a particular time, used to display weather patterns and conditions. A synoptic chart, also known as a weather chart, is an essential tool in marine navigation and meteorology, providing a comprehensive overview of atmospheric conditions. It is constructed using data collected from numerous observation...

The alignment of three celestial bodies—typically the Earth, Moon, and Sun—along a straight line, often resulting in phenomena such as tides, eclipses, or new and full moons. Syzygy refers to a specific astronomical alignment where three celestial bodies, most commonly the Earth, Moon, and Sun, are positioned in a straight line. This alignment occurs during...

Verb: To change the direction of a sailing vessel by turning its bow through the wind, allowing the wind to shift from one side of the sail to the other. Noun: The course or direction a sailing vessel takes relative to the wind, specifically when sailing at an angle to the wind. In sailing, "tack" is a...

The lower forward corner of a sail, where it is secured to the boat or rigging.  The tack of a sail is the point where the luff (leading edge) and the foot (bottom edge) meet, typically attached to the boat or rigging. On a mainsail, the tack is secured near the mast, while on a...

To manoeuvre or turning a sailing vessel's bow through the wind to change direction, allowing it to sail in a zigzag pattern upwind. Tacking is a fundamental sailing technique used to navigate a vessel upwind, as a sailboat cannot sail directly into the wind. Instead, the boat must follow a zigzag course, alternating between two...

Lower a sail

To assume control or responsibility for steering or navigating a vessel. Taking the helm refers to the act of assuming control over the steering of a boat or ship, typically by physically handling the wheel or tiller that directs the vessel's course. The helm is the mechanism that allows the helmsman to control the rudder,...

Pronounced: TANG-go The term for the letter T in the NATO Phonetic Alphabet.

The International Maritime Signal Flag Tango. Meaning Keep clear of me.Fishing boats: Keep clear of me; I am engaged in pair trawling.If appended with a Numeral Pennant, local time. (The first 2 digits denote hours; the last 2 denote.)

A measure used primarily in maritime and aviation contexts to estimate the time until two moving objects (e.g., ships or aircraft) reach their closest point of proximity to each other, assuming their current courses and speeds remain unchanged. It is a crucial parameter in collision avoidance systems. Key Concepts: Closest Point of Approach (CPA): The...