Strong maritime English vocabulary is not just a career advantage — it is a safety requirement. STCW conventions require all seafarers to communicate effectively in English, and shipping companies routinely screen candidates using English proficiency tests such as MARLINS and CES. But beyond passing tests, knowing the right terms on the bridge, in the engine room, and during radio communications can prevent accidents and save lives.
This guide covers the essential maritime English vocabulary organised by operational area, with clear definitions and context. Bookmark it, study it section by section, and use it as a reference during your sea service preparation.
1. Navigation and Bridge Terms
The bridge is the operational centre of the ship. Every officer on watch must know these terms precisely.
- Bearing — the direction to an object measured in degrees from North (000° to 359°). A true bearing is measured from true North; a magnetic bearing from magnetic North; a relative bearing from the ship’s head.
- COG (Course Over Ground) — the actual direction the ship is moving relative to the ground, which may differ from the heading due to current and wind.
- SOG (Speed Over Ground) — the actual speed of the ship relative to the ground.
- Waypoint — a defined geographical position on the planned route, entered into the ECDIS or GPS.
- CPA (Closest Point of Approach) — the minimum distance between two vessels if they both maintain their current course and speed.
- TCPA (Time to Closest Point of Approach) — the time until CPA is reached.
- Head-on situation — two vessels approaching each other on reciprocal or nearly reciprocal courses, each altering to starboard per COLREGS Rule 14.
- Overtaking situation — a vessel coming up on another from more than 22.5° abaft the beam; the overtaking vessel gives way.
- Cross-track error (XTE) — the distance the vessel has deviated from the planned track line.
- Squat — the reduction in underkeel clearance (and change in trim) experienced by a vessel moving through shallow water at speed.
- Turning circle — the path described by a ship when making a full 360° turn at constant rudder angle and engine setting.
- Advance — the forward distance travelled from the point where the helm is put over to the point where the vessel has turned 90°.
- Transfer — the lateral distance from the original track to the position where the vessel has turned 90°.
2. Radio Communication and SMCP Terms
Radio communications at sea follow the IMO Standard Marine Communication Phrases (SMCP). These are the phrases you must know for bridge watch, GMDSS, and any VHF exchange with port control or other vessels.
- Mayday — the international distress signal, repeated three times at the start of a distress call. Indicates a vessel or person in grave and imminent danger requiring immediate assistance.
- Pan-Pan — urgency signal, repeated three times. The vessel has a very urgent message to transmit concerning safety of the ship or of a person.
- Sécurité — safety signal, repeated three times. Used to announce a navigational hazard or important meteorological warning.
- Over — my transmission is complete and I am awaiting your reply.
- Out — the conversation is over and no reply is expected.
- Roger — I have received and understood your last transmission.
- Wilco — I have received and understood your instruction and will comply.
- Say again — please repeat your last transmission (do not use “repeat” in maritime radio — it has a different meaning).
- Affirm / Negative — yes / no (used in formal radio communications).
- VTS (Vessel Traffic Services) — shore-based system for monitoring and managing vessel movements in port approaches and confined waters.
- ETА (Estimated Time of Arrival) — the predicted time a vessel will arrive at a specific location.
- ETP (Estimated Time of Passing) — the predicted time a vessel will pass a specific point.
3. Safety and Emergency Terms
Safety vocabulary must be instantly understood in high-pressure situations. Hesitation caused by a language barrier in an emergency can have fatal consequences.
- Muster station — the designated assembly point where crew and passengers gather during an emergency.
- Abandon ship — the order given by the master when the vessel must be evacuated immediately.
- Man overboard (MOB) — a person has fallen into the sea. The immediate action includes shouting “Man overboard!”, throwing a lifebuoy, and pressing the MOB button on the GPS/ECDIS.
- Fire damper — a device in ventilation systems that closes automatically (or manually) to prevent the spread of fire and smoke through ducts.
- Watertight integrity — the condition of a ship in which all openings below the waterline are sealed, preventing progressive flooding.
- EPIRB (Emergency Position-Indicating Radio Beacon) — a device that transmits a distress signal to COSPAS-SARSAT satellites upon activation, enabling search and rescue authorities to locate the vessel.
- SART (Search and Rescue Transponder) — a radar transponder that responds to a ship’s radar signal, appearing as a distinctive line of dots on the radar screen.
- Immersion suit — a protective garment (also called a survival suit) worn in cold water survival situations to prevent hypothermia.
- Mustering — the process of gathering all crew and passengers at assigned muster stations for a drill or actual emergency.
- Enclosed space — any space with limited openings for entry/exit, poor ventilation, and the potential for oxygen-deficient or toxic atmospheres (e.g. ballast tanks, cargo holds, void spaces).
4. Cargo Operations Terms
Officers and ratings involved in cargo operations need precise vocabulary to avoid dangerous mistakes, particularly when working with bulk cargo, containers, tankers, or ro-ro vessels.
- Bill of Lading (B/L) — a legal document issued by a carrier to acknowledge receipt of cargo for shipment, which also serves as a document of title to the goods.
- Stowage factor — the volume in cubic metres (or cubic feet) occupied by one metric tonne of a particular cargo; used to calculate how much cargo will fill the available space.
- Draft survey — a method of determining the weight of cargo loaded or discharged by measuring the ship’s displacement before and after the operation.
- Ullage — the distance from the top of a tank to the surface of the liquid inside; used in tanker operations to calculate the quantity of liquid cargo.
- Innage (Dip) — the depth of liquid in a tank measured from the bottom; the complement of ullage.
- Cargo securing manual — a ship-specific document approved by the flag state that prescribes how different cargo types must be secured for sea passage.
- Lashing — ropes, chains, or straps used to secure cargo to prevent movement during sea passage.
- Jettison — the deliberate act of throwing cargo or equipment overboard to lighten a vessel in an emergency.
- Broken stowage — the space in a cargo hold that cannot be filled due to the irregular shape of the cargo or the hold itself.
- Dangerous goods (IMDG Code) — cargo classified as hazardous under the International Maritime Dangerous Goods Code; must be stowed, segregated, and documented according to strict rules.
5. Mooring and Port Operations Terms
Arriving in port and mooring safely requires clear communication between the deck team, the bridge, and shore personnel. These terms are used daily during berthing and unberthing operations.
- Headlines / Headropes — mooring lines running from the bow forward to the berth; they prevent the ship’s bow from moving away from the quay.
- Sternlines — mooring lines running aft from the stern; they hold the stern in place.
- Springs — mooring lines running forward and aft at an angle to the ship’s length; they prevent the vessel from moving ahead or astern along the quay. A forward spring runs aft from the bow; an after spring runs forward from the stern.
- Breast lines — mooring lines running at right angles to the ship’s side; they keep the vessel close to the quay.
- Bollard — a thick post on a quay to which mooring lines are secured.
- Capstan / Winch — a powered rotating machine used to heave in mooring lines and anchor chains.
- Fairlead — a fitting on a ship’s side or deck that guides a mooring line to prevent chafing.
- Make fast — to secure a mooring line; opposite is let go or cast off.
- Surge — to allow a line to slip through slowly under controlled tension; distinct from letting go completely.
- Pilot ladder — a rope ladder with rigid wooden steps hung over the ship’s side to allow the pilot to board or leave the vessel.
6. Engine Room and Technical Terms
Engine officers need precise technical English to communicate with manufacturers, port engineers, and classification society surveyors, as well as to read technical manuals accurately.
- Scavenge fire — a fire that occurs in the scavenge space of a two-stroke diesel engine, caused by oil deposits igniting; one of the most common engine room emergencies.
- Crankcase explosion — an explosion inside the crankcase of a diesel engine caused by ignition of an oil mist; extremely dangerous and a major cause of machinery space casualties.
- Bilge — the lowest internal part of a ship’s hull where water and oil accumulate; the bilge system drains this water overboard or to a holding tank.
- Purifier / Separator — a centrifugal machine used to separate water and impurities from fuel oil or lubricating oil.
- Viscosity — a measure of a fluid’s resistance to flow; fuel oil must be heated to the correct viscosity before injection into a diesel engine.
- Turbocharger — a turbine driven by exhaust gases that compresses air entering the engine cylinders, increasing efficiency and power output.
- OWS (Oily Water Separator) — equipment that separates oil from bilge water before the water is discharged overboard; required to reduce oil content below 15 ppm as per MARPOL.
- ORB (Oil Record Book) — a mandatory log in which all machinery space operations involving oil (bilge pumping, tank cleaning, fuel transfers) must be recorded.
- Overhaul — a major service or inspection of machinery involving disassembly, inspection, repair or replacement of worn parts, and reassembly.
- Running hours — the total operating time of a piece of machinery since last overhaul or since new; used to determine maintenance intervals.
7. Weather and Meteorological Terms
Understanding weather forecasts and being able to communicate weather conditions accurately is essential for route planning and safe navigation.
- Beaufort Scale — an international scale from 0 (calm) to 12 (hurricane) describing wind speed and its observable effects on sea conditions.
- Swell — waves generated by distant winds, now moving beyond the area where they were created; distinguished from wind waves or seas generated by local wind.
- Sea state — the general condition of the sea surface, typically described by wave height and period.
- Squall — a sudden, sharp increase in wind speed lasting at least one minute, often accompanied by rain or hail.
- Tropical cyclone — an intense circular storm originating over tropical oceans with sustained winds exceeding 63 knots; also called a hurricane (Atlantic/East Pacific) or typhoon (West Pacific).
- Depression — an area of low atmospheric pressure, associated with unsettled weather, strong winds, and cloud.
- Visibility — the greatest distance at which an object can be seen and recognised in daylight conditions; critical for the application of the Collision Regulations.
- NAVTEX — an automatic radio broadcasting system transmitting weather forecasts, navigational warnings, and search and rescue information on 518 kHz.
Tips for Learning Maritime Vocabulary Effectively
- Learn terms in context — do not memorise isolated words. Always study a term with an example sentence or scenario showing how it is used on board.
- Group vocabulary by topic — studying navigation terms together, then cargo terms together, makes connections and reduces cognitive load.
- Use the terms actively — write a log entry using five new terms, describe a navigation scenario aloud, or explain a procedure in English to a colleague.
- Read original maritime documents — standing orders, cargo plans, port authority notices, and equipment manuals are excellent authentic reading material.
- Review regularly — spaced repetition (reviewing terms after 1 day, then 3 days, then a week) is the most efficient method for long-term retention.
Build Your Maritime English with Sea Service
Knowing vocabulary is the foundation, but using it accurately under pressure — in radio communications, during PSC inspections, or in emergency situations — requires systematic training and practice. At Sea Service, our maritime English courses are designed specifically for Ukrainian seafarers who want to advance their careers and perform confidently in any international maritime environment.
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