In highly globalized maritime industry, communication at sea is far more than a matter of technology—it is a matter of safety, operational efficiency, and even life preservation. Every task on board a vessel—whether it’s navigating through open waters, berthing, departing a port, anchoring, cargo operations, or emergency responses—relies on clear, unambiguous communication. Especially during adverse weather, low visibility, mechanical failure, or when navigating complex channels, even a minor misunderstanding in verbal exchanges can lead to severe consequences such as collisions, groundings, operational delays, or safety breaches.
To mitigate these risks and enable effective communication between multilingual, multicultural seafarers, the Standard Marine Communication Phrases (SMCP) were developed. SMCP provides a universally accepted and structured set of phrases in English, designed to be used across international maritime operations to ensure clarity, eliminate confusion, and promote safety. It serves as the maritime industry’s equivalent of the standardized radio phraseology used by pilots and air traffic controllers in aviation.
The development of SMCP was a result of lessons learned from decades of marine incidents where communication breakdown played a critical role. It traces its roots back to 1973, when the International Maritime Organization (IMO) introduced the Standard Marine Navigational Vocabulary (SMNV) to unify frequently used English phrases in shipboard and navigational communications. However, with the rapid evolution of maritime operations, SMNV was soon deemed insufficient in scope and depth. Recognizing the need for a more comprehensive framework, the IMO officially adopted the Standard Marine Communication Phrases (SMCP) in 2001 through Resolution A.918(22), replacing SMNV.
SMCP was created not only to cover ship-to-ship and ship-to-shore communication but also to standardize onboard communication among multilingual crew members. This holistic approach made it a powerful tool for enhancing situational awareness, operational precision, and the overall safety culture on vessels.
The philosophy behind SMCP is simple yet powerful: eliminate ambiguity, ensure clarity, and make communication universally comprehensible. This means avoiding vague expressions, idioms, regional slang, or complex grammar structures. Instead, SMCP favors direct and concise statements that can be easily understood even under stressful conditions or poor radio quality. For example, instead of responding with a simple “Yes,” a seafarer is expected to reply, “Yes, this is vessel Morning Star,” ensuring the message is self-contained and unambiguous.
SMCP is organized into two main categories: external communication and internal communication. External communication encompasses exchanges between vessels, between ship and shore authorities (such as port control or VTS), or between a vessel and aircraft or search-and-rescue coordination centers. These interactions primarily occur over radio systems, especially VHF, and must also comply with International Telecommunication Union (ITU) radio regulations.
Internal communication, on the other hand, refers to the verbal exchanges among crew members onboard, including bridge-to-engine-room commands, safety drills, firefighting coordination, mooring operations, and emergency response. By using SMCP internally, crew members can perform complex tasks more efficiently and respond to emergencies more effectively, regardless of their native language or language proficiency level.
One of the most distinctive features of SMCP is its strict use of the NATO phonetic alphabet, also known as acrophony. This system is used when spelling out ship names, technical terms, or positions to prevent confusion due to similar-sounding letters or strong accents. For instance, when spelling “RADAR” over the radio, a crew member should say “Romeo – Alfa – Delta – Alfa – Romeo,” instead of the more informal “R for Rabbit,” which lacks standardization and may be misinterpreted.
Numerical communication is also carefully regulated under SMCP. All numbers must be pronounced digit by digit to avoid misinterpretation, particularly in noisy environments or during emergency situations. For example, the number 175 must be spoken as “One – Seven – Five,” not “One seventy-five.” Furthermore, the number 0 must be stated as “Zero,” and never “O” or “Nought.” These seemingly small rules play a crucial role in avoiding misunderstandings, especially when reporting coordinates, distances, speeds, or times.
When it comes to expressing positions or movements, SMCP requires the use of cardinal directions and internationally accepted nautical terminology. Distances must be expressed in nautical miles, and speeds in knots. For instance, a position report would be structured as: “My position is three-five degrees North, one-two-zero degrees East.” This clarity ensures that all parties involved have a precise understanding of where a vessel is located and how it is moving.
Another major principle of SMCP is the elimination of modal and conditional language, which can lead to misinterpretation or hesitation. Phrases like “Can I,” “Could we,” “Should we,” or “May I” are considered too ambiguous for use in high-stakes marine operations. Instead, SMCP mandates that questions and commands be formulated in a more assertive and specific format. For example, a request for entry into a port channel should be stated as: “Question. Do I have permission to enter the channel?” rather than “Can I enter the channel?” Likewise, an iceberg warning should be delivered as: “Danger. Do not proceed. Ice ahead,” instead of “You should not proceed. There might be ice.”
To reinforce critical information or request clarification, SMCP prescribes standardized tools. If a message must be emphasized or repeated for safety, the phrase “Repeat” is used: “Do not proceed. Traffic ahead. Repeat. Do not proceed.” Similarly, if a message is unclear, the standard response is “Say again (please),” avoiding informal replies like “Pardon?” or “Sorry?” In the event of a misstatement or correction, the phrase “Mistake. Correction:” is used, followed by the accurate message.
Of particular importance are the globally recognized distress and safety signals, which SMCP incorporates without modification. These include:
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MAYDAY – Signaling a vessel is in grave and imminent danger and requires immediate assistance.
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PAN PAN – Indicating an urgent situation that does not pose an immediate threat to life (e.g., engine failure, lost rudder).
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SECURITE – Used for safety messages related to navigation or weather conditions.
These terms are used in strictly defined contexts and cannot be substituted or altered in any way.
In practical maritime operations, SMCP has proven indispensable not only during navigation but also during port operations, cargo loading and unloading, towing, pilot boarding, inspections, bunkering, and interaction with regulatory bodies like customs, immigration, and quarantine. These interactions often occur under tight schedules and with multiple stakeholders involved. A common communication framework like SMCP helps eliminate delays, reduce misunderstandings, and streamline operational coordination.
SMCP has also been incorporated into maritime training curricula worldwide. Under the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW), all watchkeeping officers and personnel with bridge or engine room responsibilities must be proficient in SMCP. Most maritime academies and training institutes have integrated SMCP into simulator training, oral assessments, and VHF communication exercises. Through role-playing scenarios and realistic simulations, cadets and seafarers develop fluency in using standardized phrases in a variety of operational and emergency settings.
Despite its value, the consistent application of SMCP still faces several challenges. Differences in English proficiency, heavy regional accents, and informal communication habits can reduce its effectiveness. In older vessels, outdated communication equipment may further limit clarity. Some crew members may also revert to their native language or colloquial English, especially in non-critical situations, undermining the standardized framework. For this reason, continuous training, evaluation, and reinforcement by ship management companies, captains, and maritime regulators are essential.
Looking ahead, the development of artificial intelligence (AI), automatic speech recognition (ASR), and text-to-speech (TTS) technologies holds promise for the evolution of maritime communication. Integrated bridge systems equipped with voice assistants may soon support SMCP by providing real-time suggestions, correcting pronunciation, and translating standardized phrases. Advanced maritime software is also incorporating SMCP into VHF communication modules, enabling automatic logging, semantic analysis, and alert generation to enhance onboard communication reliability.
In essence, SMCP is more than a list of phrases—it is a comprehensive safety system, a behavioral protocol, and a bridge between individuals, cultures, and professional practices. By promoting shared understanding through language, it reduces uncertainty and fosters a proactive safety culture aboard ships. For international crews working under pressure in dynamic, high-risk environments, SMCP is not just helpful—it’s indispensable.
Whether you are a new cadet entering the maritime profession, a seasoned master mariner, or a shoreside VTS officer, understanding and applying SMCP should be considered part of your core professional responsibility. It ensures that every command, report, or inquiry is delivered in the clearest, most universally understandable way, especially when it matters most.
Behind the mechanical precision and steel infrastructure of the shipping industry lies a very human element: language. And within that language, Standard Marine Communication Phrases stand as one of the most important tools for maintaining clarity, safety, and professionalism at sea.
For further study and comprehensive reference, the IMO’s official SMCP manual is available through authorized maritime publishers and should be part of every bridge officer’s training materials and onboard documentation.