Glossary
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TermDefinition
- General Nautical Terminology Tender
A small boat used to transport people or goods between a larger vessel and the shore or another vessel.
A tender is an essential component of...
More Details - Courses, RYA Tender OperatorThe RYA Tender Operator course is tailored for individuals using tenders in marina or superyacht environments. The course covers low-speed... More Details
- General Nautical Terminology, Weather (Meteorology) Thames
Sea area of the Met Office Shipping Forecast. Covers waters off southeast England, centered on the Thames Estuary.
From the River Thames...
More Details - Organisation The Royal Institution of Naval Architects (RINA)
An internationally renowned professional institution representing naval architects and marine engineers worldwide. It was founded in 1860 and is...
More Details - Flag / Pennant, Signals & Communication Third Substitute (ICS Flag)

Substitute or repeater flags allow messages with duplicate characters to be signalled without requiring multiple sets of flags.
- Did you know?, Nautical Saying Three sheets to the wind
The phrase “three sheets to the wind” comes straight from nautical life—and originally had nothing to do with drinking at all!
🚢 Nautical...
More Details - General Nautical Terminology, Navigation Tidal Stream
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...
More Details - General Nautical Terminology, Navigation Tidal Stream Atlas
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...
More Details - General Nautical Terminology, Navigation Tide
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...
More Details - General Nautical Terminology, Navigation Tide Tables
Charts or listings that provide the predicted times and heights of high and low tides for specific coastal locations over a given period.
Tide...
More Details - General Nautical Terminology TillerA lever attached to the rudder head by which the helmsman moves the rudder
- General Nautical Terminology, Navigation Time Dilution of Precision (TDOP)
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...
More Details - General Nautical Terminology, Navigation Time to Closest Point of Approach (TCPA)
A measure used primarily in maritime and aviation contexts to estimate the time until two moving objects (e.g., ships or aircraft) reach their...
More Details - General Nautical Terminology, Navigation Time to Go (TTG)Estimated time remaining to a waypoint giving an indication of arrival time
- General Nautical Terminology, Navigation Time Zone (TZ)
A region of the Earth where the same standard time is used.
A time zone is a geographical area that observes a uniform standard time for...
More Details - Flag Semaphore, Signals & Communication Letter T (Flag Semaphore)

Flag semaphore indicating the letter T.
- Morse Code, Signals & Communication Letter T (Morse Code)
International Morse Code sequence representing the letter T.
- General Nautical Terminology Toe Rail
A low, raised edge running along the outer perimeter of a boat's deck, designed to provide footing stability and prevent gear or crew from...
More Details - General Nautical Terminology Topping Lift
A line or wire used to support the boom of a sailboat when the sail is not hoisted, or to adjust the height of a spinnaker pole.
A topping...
More Details - General Nautical Terminology Topsides
The outer hull of a vessel above the waterline, extending from the deck to the water's edge.
The term "topsides" is a fundamental concept in...
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