Technical navigation glossary
Navigating at sea requires a good knowledge of specific technical vocabulary.
Learning maritime language is essential to ensure safety, carry out efficient maneuvers and communicate clearly between crew members or with other vessels.
In this glossary, Orca Retail has grouped together the main technical terms of navigation at sea, from ship parts to instruments, mechanics, weather, safety and communication.
Whether you're an amateur or a professional, you'll find the essential terms to help you understand the maritime world.
Ship structure and parts
- Tack strip Reinforced or protected part of the boat's plating, often located at the waterline, designed to protect the hull from rubbing, bumping or scratching when docking or passing through congested waters.
- Port: Left side of the boat looking forward.
- Tiller: Large pivoting tiller used to steer the rudder.
- Boom: Horizontal beam attached to the base of the mast, controlling the mainsail.
- Hull: Submerged part of the boat, providing buoyancy and stability.
- Halyard: Cable or rope used to hoist a sail or flag.
- Sheet: Rope used to adjust the tension and direction of a sail.
- Livard: Small auxiliary sail attached to the back of the mast to improve balance.
- Mast: Vertical pole supporting the sails.
- Bulwark: Vertical planking above the deck protecting the crew.
- Bilge pump: Device used to evacuate water accumulated in the bilge to maintain the boat's buoyancy and safety.
- Deck: Rigid platform, reinforced by longitudinal and transverse members, which protects the interior of the boat from water and supports the loads carried.
- Bow: Forward part of the vessel, which breaks waves during navigation.
- Stern: Rear part of the boat, often where the propeller or engine is located.
- Chain well: Anchor chain storage compartment, often located at the bow of the boat.
- Daggerboard well: Housing in the hull for vertically sliding a daggerboard, used in particular on dinghies and sailboards to reduce lateral drift.
- Rouf: Superstructure on deck, corresponding to the cabin roof, protecting the interior spaces.
- Rudder: Submerged rudder, movable part under the hull which steers the boat by deflecting the flow of water.
- Tiller: Element to which the tiller or steering wheel is attached.
- Starboard: Right-hand side of the boat looking forward.
- Lining: The interior lining of the boat, providing comfort and insulation.
Instruments, units and measurements
- Anemometer: Instrument for measuring wind speed.
- Barometer: Device measuring atmospheric pressure, useful for marine weather forecasting.
- Gyro compass: Instrument indicating true north corrected for magnetic declination.
- Magnetic compass: Indicates the direction of magnetic north.
- Degrees (°): Unit for measuring angles (heading, bearing).
- GPS: Global Positioning System, providing precise latitude and longitude.
- Weathervane: Indicates wind direction.
- Loch: Instrument measuring boat speed through the water.
- Nautical mile (NM): Unit of distance equal to 1852 meters.
- Knot (kt): Unit of speed equal to one nautical mile per hour (1 kt ≈ 1.852 km/h).
- Inch: Anglo-Saxon unit of length equal to 2.54 centimeters.
- Radar: Electronic device used to detect and locate objects at sea, useful for navigation and safety.
- Direction finder: Radio instrument used to determine the direction of a transmitting source, such as a beacon, as an aid to navigation.
- Speedometer (speedo): Instrument for measuring boat speed in water.
- Sounder (sonar): Instrument using acoustic waves to measure the depth beneath the boat.
- Tonneau: Unit of volume equal to 10 cubic feet (~283 liters). By extension, it is also a unit of calculation used for a boat's tonnage, expressing the total volume of the vessel.
- VHF: Abbreviation for Very High Frequency. Communication system using metric waves, particularly suited to coastal navigation. Includes a safety channel (channel 16) with a 24-hour watch.
- PVC: Synthetic fabric coated with polyvinyl chloride, used in the manufacture of inflatable hulls and other water-resistant components.
Mechanics and motorization
- Alternator: Device producing electricity from the rotation of the engine.
- Anode: Galvanic protection against corrosion on submerged metal parts of the motor or hull.
- Battery: Source of electrical energy for starting and powering systems.
- Clutch: Mechanism for connecting or disconnecting the motor from the transmission.
- Propeller: Rotating member under the stern, generating the boat's propulsion.
- Injector: Part of the fuel supply system.
- Outboard motor: Motor installed outside the hull, usually at the stern.
- Inboard engine: Engine located inside the hull, transmitting power to the propeller via a propeller shaft.
- Seawater pump: System for cooling the engine by circulating seawater.
- Bow thruster: Propeller located at the front of the boat, perpendicular to the main axis, facilitating maneuvering in harbor and tight spaces.
- Gearbox: A gearbox that adapts the speed of the motor to that of the propeller.
- Turnbuckle: Metal device for tensioning a rope or clew, essential for rig stability.
- Transmission: All the elements transmitting power from the motor to the propeller.
- Trolling valve: Hydraulic system for fine control of boat speed at slow speeds, much appreciated by fishermen.
- Flywheel: Rotating mass used to regulate motor rotation.
- Winch: Manual or electric winch used to line sheets or tension halyards, available in different sizes and types to suit different needs.
- Zeus PROJET: Motorized steering system, coupled with a joystick, developed by Cummins MerCruiser Diesel for optimum maneuverability.
Maneuvers and speeds
- Points of sail: Position of the boat in relation to the wind direction.
- Full: Pitch between 45° and 60° to the wind.
- Gybe: Change of tack by passing the wind from astern, a tricky maneuver.
- Jib: Triangular headsail.
- Largue: Gearing with the wind coming from astern at an angle greater than 90°.
- Close-hauled: Tight to windward, between 0° and 45°.
- Recoil: Technique used by the crew to increase the boat's righting by shifting to windward, sometimes aided by equipment such as trapezes.
- Rise: Sudden increase in wind strength, often requiring a reduction in sail area.
- Roll bar: A hoop placed at the stern of the boat, used in particular to attach lights and antennas, and offering protection against overturning.
- Tacking: Changing the direction of the boat by passing the bow into the wind.
- Tailwind: Allure with the wind coming directly from astern (180°).
- Headwind: Wind coming from the front, impossible to sail in this direction.
Weather and sea conditions
- Mooring bar: Wave breaking area at the entrance to a harbor or on a sandbank.
- Currents: Water movements influenced by tide, wind or topography.
- Foehn: Warm, dry wind blowing down from the mountains, locally affecting the sea.
- Grain: Sudden downpour accompanied by strong winds.
- Swell: Regular series of long waves generated by a distant wind.
- Rough seas: Rough seas with large waves and strong winds.
- Meteogram: Graph showing the forecast evolution of weather and sea conditions.
- Reflux: Falling phase of the tide.
- Spring tide: A tide with a high coefficient, causing significant variations in water level.
Safety
- Mooring line: Rope or cable used to secure a boat to a dock or buoy.
- Damage: Damage or breakdown affecting the vessel.
- Sheer: Sudden and involuntary deviation from the boat's trajectory.
- Launching: Action of lowering a canoe or raft into the water.
- Mayday: Urgent international distress signal.
- Pan-pan: Radio emergency signal less serious than Mayday.
- Pontoon: Floating dock where the boat is moored.
- Priority rules: Standards governing passage between ships at sea.
- Airlock: Watertight compartment between two spaces.
- Waterway: Accidental opening in the hull through which water penetrates.
- Drain: Hole usually located at the base of the transom for rapidly evacuating shipped water.
Navigation and steering terminology
- Azimuth: Horizontal angle measured clockwise from north towards an object.
- Heading: Direction towards which the boat is oriented (0°-360°).
- Magnetic course (CM): Direction taken in relation to magnetic north.
- True course (CV): Direction taken in relation to true north.
- Drift: Lateral deviation of the boat caused by wind or current.
- Layline: Imaginary line indicating the optimum trajectory towards a mark.
- Bearing: Angle between the bow and a reference point.
- Course: Trajectory followed by the boat on the water.
Expressions and communication at sea
- À la cape: Position of the boat facing the wind.
- Bâbord amure: Wind coming from port (left).
- Mettre les gaz: Colloquial expression for accelerating.
- Pan-pan: Non-vital emergency radio signal.
- Prendre le large: To leave port and go out to sea.
- International signals: Standardized system for communicating in emergency situations (Mayday, Pan-pan, Safety).
- VHF signals: Radio communications between boats and with land.
- Starboard tack: Wind coming from starboard (right).
Types of boat
- Barge: Flat boat, often used for transporting goods on inland waterways.
- Barque: Small traditional boat, often rowed.
- Motorboat: Vessel powered by one or more internal combustion engines or electric motors.
- Fishing boat: Designed specifically for catching fish, with adapted equipment.
- Inflatable boat: Lightweight inflatable boat, appreciated for its portability and ease of use.
- Canoe: Small, light boat, often with oars or a light motor, used for short distances.
- Catamaran: Boat with two parallel hulls, offering great stability and space.
- Trawler: Type of fishing boat specialized in trawling, with the net dragged behind the boat.
- Prao: Outrigger canoe from Oceania, ancestor of modern multihulls.
- Runabout: Small motorboat (under 9 meters) designed for cruising, waterskiing or fishing.
- Semi-rigid: Inflatable boat whose hull is reinforced by a rigid structure, offering stability and sturdiness.
- Trapeze: Harness used in sailing to allow the sailor to lean out of the boat, increasing stability and balance.
- Trimaran: Three-hulled boat combining speed and stability.
- Vedette: Small, fast boat, often used for surveillance or rapid intervention.
- Sailboat: Boat propelled mainly by sails.
- Yacht: Pleasure boat, often large, equipped for cruising or racing.
Conclusion
Navigation at sea is a world rich in technical vocabulary, necessary for precise understanding of maneuvers, clear communication and crew safety.
To help you master the art of navigation, Orca Retail offers resources, equipment and training adapted to all those who are passionate about the sea.
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