Glossary
-
TermDefinition
- General Nautical Terminology Raster chartElectronic chart which is a direct copy of a paper chart with limited zooming capability
- General Nautical Terminology, Navigation Rate (Tidal Stream)
The speed at which a tidal stream flows, typically measured in knots.
The rate of a tidal stream is the velocity at which the water moves due...
More Details - Flag / Pennant, Signals & Communication Code Flag Romeo (R)

The International Maritime Signal Flag Romeo.
Meaning
Distance (range) in nautical miles. Given using Numeral Pennants.
- General Nautical Terminology Reach
The point of sail where the wind is coming from the side of the boat, roughly perpendicular to the direction the boat is travelling.
A reach...
More Details - General Nautical Terminology ReachingSailing across the wind: from about 60° to about 160° off the wind. Reaching consists of "close reaching" (about 60° to 80°), "beam reaching"... More Details
- General Nautical Terminology Ready AboutThe helmsman’s shout that he intends to go about shortly
- Flag Semaphore Ready (Flag Semaphore)

The Ready (Flag Semaphore) signal shows the sender is ready to send a message. The same shape is also used for Space (Flag Semaphore) & Rest...
More Details - Flag Semaphore Ready to Recieve (Flag Semaphore)

The Ready to Recieve signal shows the sender that the recipient is ready to receive a message. This shape is displayed once the sender has...
More Details - General Nautical Terminology Reef
A reef is a submerged ridge of rock, coral, or sand near the surface of oceans or seas. It can be made up of living organisms like coral or...
More Details - General Nautical Terminology Reefing
The act of reducing the area of a sail to decrease wind exposure and maintain control in strong winds.
Reefing is an essential technique in...
More Details - General Nautical Terminology, Parts of a Boat Reefing Hook
A curved metal fitting on a boom or mast used to secure the reefing cringle of a sail when reducing its area in strong winds.
A reefing hook...
More Details - General Nautical Terminology, Parts of a Boat Reefing Lines
Ropes or cords used to reduce the sail area by securing a portion of the sail to the boom or mast, thereby making the vessel more manageable in...
More Details - Flag Semaphore Rest (Flag Semaphore)

When the sender is not actively sending messages, both flags are held by their side. The same shape is also used for Space (Flag Semaphore) &...
More Details - Abbreviation, General Nautical Terminology Restricted in Ability to Manoeuvre (RAM)
A ship that, due to the nature of its work, is unable to keep out of the way of other vessels as required by the International Regulations for...
More Details - General Nautical Terminology Restricted Visibility
Conditions in which a vessel's ability to see is significantly reduced due to environmental factors such as fog, heavy rain, snow, or...
More Details - General Nautical Terminology Rhumb LineA line on the surface of the earth that cuts all meridians at the same angle. On a standard Mercator chart the rhumb line appears as a straight line
- General Nautical Terminology Riding Turn
A loop of rope that crosses over itself on a winch drum or cleat, often causing friction or jamming.
A riding turn is a term commonly used in...
More Details - General Nautical Terminology Rigging
The system of ropes, cables, chains, and other apparatus used to support and control the sails and masts of a sailing vessel.
Rigging is...
More Details - General Nautical Terminology Rigging
Verb - The process of setting up and adjusting the sails, lines, and other necessary equipment on a boat or ship to ensure it is ready for...
More Details - General Nautical Terminology Rigid Inflatable BoatA vessel that has both a solid part and inflatable part to its structure

