International Maritime Organization (IMO)

International Maritime Organization (IMO) is the United Nations specialized agency responsible for regulating shipping. Its work is expressed through a series of conventions, codes and recommended practices that together form the legal and technical framework governing maritime safety, security and environmental protection. Mastery of the key terminology used in these instruments is essential for anyone studying the IMO system. The following explanation presents the most frequently encountered terms, provides practical examples of how they are applied, and highlights common challenges faced by practitioners.

Convention – A formal international treaty that creates binding obligations for the states that ratify it. The IMO’s most influential conventions include the International Convention for the Safety of Life at Sea (SOLAS), the International Convention for the Prevention of Pollution from Ships (MARPOL), the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW) and the International Convention on the Establishment of an International Maritime Organization (IMO Constitution). Conventions are adopted by the IMO Assembly and enter into force after a specified number of states have ratified them.

Protocol – An amendment or addition to an existing convention that introduces new provisions or updates existing ones. For instance, the Protocol of 1978 to the STCW Convention (STCW 1978) and the Protocol of 1992 to SOLAS (SOLAS 1992) are essential extensions that address emerging safety and environmental concerns. Protocols require separate ratification and may have distinct entry‑into‑force dates.

Code – A set of detailed rules that operationalize the principles of a convention. The International Ship and Port Facility Security (ISPS) Code operationalizes the security provisions of SOLAS Chapter XI‑2, while the International Safety Management (ISM) Code translates the safety management requirements of SOLAS Chapter IX into practical procedures for ship owners and operators. Codes are mandatory for ships that fall within the scope of the underlying convention.

Resolution – A non‑binding decision adopted by the IMO Council or Assembly that provides guidance, encourages best practice, or clarifies interpretation of existing instruments. Resolutions often address emerging issues such as ballast water management, cyber risk, or the implementation of the Polar Code. Although not legally binding, resolutions influence national legislation and industry standards.

Flag State – The country whose flag a vessel flies and under whose laws the vessel is registered. The flag state is responsible for ensuring that the ship complies with all relevant IMO conventions, for conducting inspections and surveys, and for issuing certificates such as the International Load Line Certificate and the Safety Management Certificate. A ship may change flag (re‑flag) to benefit from more favorable regulatory regimes, but the new flag state assumes all obligations.

Port State – The state whose ports a vessel visits. Port‑state control (PSC) authorities have the right to inspect foreign ships to verify compliance with international standards. PSC inspections can lead to detention, deferral of entry, or the issuance of non‑conformity notices if deficiencies are found. Effective PSC programs complement flag‑state oversight and help prevent sub‑standard ships from operating.

Flag of Convenience – A flag state that offers registration with minimal regulatory oversight, lower fees, and often lax enforcement of safety and labor standards. Common examples include Panama, Liberia and the Marshall Islands. While the practice is legal, it raises concerns about “regulatory arbitrage,” where ship owners choose flags primarily to reduce compliance costs rather than to ensure safety.

Ship‑Owner – The legal entity that possesses the title to a vessel and is ultimately responsible for its operation, maintenance and compliance. The ship‑owner may delegate day‑to‑day management to a ship management company, but retains accountability for meeting IMO obligations and for ensuring that the crew holds appropriate certifications.

Ship‑Management Company – A specialized firm that provides technical, crewing and administrative services on behalf of the ship‑owner. The management company prepares the Ship‑Specific Safety Management System, arranges for regular surveys, and ensures that crew members are trained in accordance with STCW. Under the ISM Code, the management company and the ship‑owner share responsibility for safety performance.

Classification Society – An organization that establishes technical standards for the design, construction and periodic survey of ships. Classification societies such as Lloyd’s Register, DNV GL and the American Bureau of Shipping conduct statutory surveys on behalf of flag states. Although classification societies are not part of the IMO, they play a critical role in verifying compliance with SOLAS and other conventions.

Survey – An inspection or examination performed to assess a vessel’s condition and compliance with specific requirements. Surveys are categorized as Initial, Annual, Interim or Special. For example, the SOLAS Special Survey occurs every five years and covers structural integrity, fire safety equipment, and lifesaving appliances. Failure to pass a survey can result in the suspension of certificates.

Certificate – An official document issued by the flag state (or an authorized organization) that confirms a ship’s compliance with a particular convention or code. Key certificates include the International Certificate of Fitness for the Carriage of Dangerous Goods (DOC), the Certificate of Compliance (COC) for MARPOL Annex VI, the Document of Compliance (DOC) for the ISM Code, and the International Ship Security Certificate (ISSC). Certificates must be presented to port‑state authorities upon request.

Document of Compliance – A certificate issued to a ship‑management company that demonstrates the company’s compliance with the ISM Code’s safety management requirements. The DOC is valid for five years and is renewed following a satisfactory audit. The DOC must be displayed on each ship managed by the company, and the ship itself receives a Safety Management Certificate (SMC) that references the DOC.

Safety Management System (SMS) – A structured set of policies, procedures and documentation that enables a ship‑owner or management company to manage safety and environmental protection. The SMS includes emergency response plans, maintenance schedules, training programs, and internal audit procedures. The ISM Code mandates that every ship operating under a flag state that has adopted the Code must have an SMS that meets the Code’s requirements.

International Load Line Certificate – A certificate that confirms a vessel’s compliance with the International Convention on Load Lines. The load line marks the maximum permissible draft under various conditions (e.g., tropical fresh water, winter North Atlantic). The certificate is crucial for ensuring that a ship is not overloaded, which could compromise stability and safety.

Stability – The ability of a vessel to remain upright and return to an even keel after being subjected to external forces such as waves, wind or cargo shift. Stability is assessed through calculations of metacentric height (GM), righting arm (GZ) curves and the distribution of weight. SOLAS Chapter II‑1 requires that ships carry a Stability Booklet that documents these calculations and provides guidance for loading and ballast operations.

Ballast Water Management – The practice of controlling ballast water to prevent the transfer of invasive aquatic species. The International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWM Convention) requires ships to have a Ballast Water Management Plan and to install approved treatment systems. Non‑compliance can result in fines and denial of entry to ports.

Ballast Water Management Plan – A written document that outlines procedures for the intake, treatment, discharge and record‑keeping of ballast water. The plan must be approved by the flag state and must reference the ship’s ballast water treatment system. The plan is subject to inspection by both flag‑state and port‑state authorities.

Pollution – Any discharge from a ship that contaminates the marine environment. Under MARPOL, pollution is categorized into oil, noxious liquid substances, harmful substances in packaged form, sewage, garbage and air emissions. Each category has specific discharge limits, record‑keeping requirements and equipment standards.

Oil‑Only Tanker – A vessel designed to carry only oil or oil products, as defined by MARPOL Annex I. Oil‑only tankers must be equipped with oil‑recording equipment, a Oil Pollution Emergency Plan (OPEP) and must comply with the International Oil Pollution Compensation Fund (IOPC Fund) requirements. The OPEP is a crucial component of the vessel’s emergency response capacity.

Oil Record Book – A mandatory logbook that records all oil cargo operations, ballast oil handling, and any oil discharge or transfer. The book must be kept on board at all times and is subject to inspection by port‑state authorities. Failure to maintain an accurate Oil Record Book can lead to severe penalties.

Garbage Management Plan – A written plan required by MARPOL Annex V that outlines procedures for the handling, storage, and disposal of ship‑generated waste, including plastics, food waste, and operational debris. The plan must be approved by the flag state and must be consistent with national waste‑acceptance facilities at ports of call.

Garbage Record Book – The logbook that documents the generation, storage, and disposal of garbage on board. It must be kept up to date and be available for inspection. The book records the type, quantity and method of disposal for each waste item, ensuring compliance with MARPOL Annex V.

Emission Control Area – Designated sea areas where stricter limits on air emissions from ships are enforced. Under MARPOL Annex VI, the NOx and SOx emission limits are tighter in ECAs such as the North Sea, the Baltic Sea, and the US Caribbean Sea. Ships operating in ECAs must use low‑sulfur fuel or install exhaust gas cleaning systems (scrubbers) to meet the standards.

Scrubber – An exhaust gas cleaning system that removes sulfur oxides (SOx) from a ship’s engine exhaust. Scrubbers enable ships to comply with the sulfur cap of 0.10% in ECAs while still using higher‑sulfur fuel oil. The installation and operation of scrubbers must be approved by the flag state and documented in the ship’s Certificate of Compliance.

Low‑Sulfur Fuel – Marine fuel oil with a maximum sulfur content of 0.10% (or 0.50% in non‑ECA waters) as mandated by MARPOL Annex VI. The adoption of low‑sulfur fuel has significant economic implications, as it often requires a price premium over high‑sulfur fuel. Ship operators must carefully manage fuel procurement and inventory to avoid inadvertent non‑compliance.

Fuel Oil Quality – The physical and chemical characteristics of marine fuel, including viscosity, density, sulfur content, and flash point. Fuel oil quality is verified by testing laboratories and documented in a Fuel Oil Quality Certificate. Incorrect fuel specifications can cause engine damage, increased emissions, and regulatory penalties.

Ship‑Specific Emergency Plan – A plan that outlines procedures for responding to emergencies such as fire, collision, grounding, or oil spill. The plan must be tailored to the ship’s size, equipment and operating area, and must be approved by the flag state. The emergency plan is a core component of the ship’s Safety Management System.

Fire‑Detection and Fire‑Extinguishing System – Equipment required under SOLAS Chapter II‑2 to detect and suppress fires on board. Systems include fixed fire detection sensors, automatic sprinkler systems, CO₂ and foam extinguishing installations, and portable fire extinguishers. Proper maintenance and regular testing are essential to ensure system reliability.

Life‑Saving Appliances – Devices required by SOLAS Chapter III to protect lives in the event of an emergency. These include lifeboats, life‑rafts, immersion suits, life‑jackets, and evacuation slides. Each appliance must be regularly inspected, serviced and fully functional. The ship’s Life‑Saving Appliance Book records all maintenance activities.

Navigation Bridge – The area of a ship where the commanding officer and bridge team conduct navigation, communication and control of the vessel. SOLAS Chapter V specifies equipment and operational standards for the bridge, including radar, AIS (Automatic Identification System), and electronic chart display and information system (ECDIS). Proper bridge resource management (BRM) is critical to safe navigation.

Automatic Identification System – A ship‑borne transponder that automatically transmits a vessel’s identity, position, course and speed to nearby ships and shore stations. AIS data enhance collision avoidance and support maritime domain awareness. AIS is mandatory for most commercial vessels over 300 gross tonnage under SOLAS and is integrated with the Global Maritime Distress and Safety System (GMDSS).

Electronic Chart Display and Information System – The electronic navigation chart system mandated by SOLAS for ships of 500 gross tonnage and above. ECDIS provides real‑time positioning, route planning, and hazard alerts. Operators must be trained and certified for ECDIS use, and the system must be approved by the flag state.

Global Maritime Distress and Safety System – An internationally standardized set of communication protocols and equipment that provides ship‑to‑ship and ship‑to‑shore distress signaling. GMDSS includes satellite (INMARSAT) and terrestrial (VHF, MF, HF) components. Compliance with GMDSS is required for vessels of 300 gross tonnage and above, ensuring rapid response to emergencies.

Inmarsat – The satellite communication system that forms part of the GMDSS, providing voice and data services such as distress alerts, safety messaging and ship‑to‑shore communications. Ships are equipped with specific Inmarsat terminals (e.g., Fleet 77, Fleet 70) that must be maintained in operational condition.

VHF Radio – Very High Frequency radio equipment used for short‑range ship‑to‑ship and ship‑to‑shore communication. VHF is essential for routine traffic, bridge‑to‑bridge coordination and the transmission of safety messages on channel 16 (156.8 MHz). VHF radios must be fitted with a digital selective calling (DSC) capability as required by SOLAS.

Distress, Urgency and Safety (DUS) Radio Services – The three categories of radio communication defined by GMDSS. Distress calls indicate immediate danger, urgency calls request assistance for non‑immediate threats, and safety calls convey navigational or weather information. Proper use of DUS services is a key competency for bridge officers.

Digital Selective Calling – A feature of VHF and satellite radios that enables automated transmission of pre‑formatted distress alerts, including the vessel’s MMSI (Maritime Mobile Service Identity) and position. DSC reduces the time required to initiate a distress call and improves the accuracy of rescue coordination.

Maritime Mobile Service Identity – A unique nine‑digit number assigned to each ship and shore station for identification in radio communications. The MMSI is used in AIS, DSC and GMDSS transmissions. It is recorded in the ship’s radio license and must be displayed on the vessel’s radio equipment.

Ship‑Radio Licence – An authorization issued by the flag state allowing a vessel to operate its radio equipment. The licence specifies the frequencies, power levels and equipment types that may be used. The licence must be renewed periodically and must be presented to authorities upon request.

Port‑State Control (PSC) – The inspection regime used by a port‑state authority to verify that foreign vessels comply with international conventions. PSC inspections are risk‑based, focusing on vessels with a history of deficiencies, older ships, or those flagged under states with known compliance gaps. PSC findings are entered into the European Union Vessel Inspection System (EVIS) or comparable regional databases.

Detention – A measure taken by a port‑state authority when a vessel is found to have serious deficiencies that pose an immediate risk to safety, security or the environment. Detention prevents the ship from leaving the port until corrective actions are taken. Detentions are recorded in the Port State Control Report and can affect the ship’s future port entry.

Deferral of Entry – A temporary restriction that allows a vessel to enter a port but requires the owner to correct identified deficiencies within a specified time frame. The ship may be allowed to continue its voyage after the corrective work is completed and verified.

Non‑Conformity Notice – A formal document issued by a port‑state authority detailing specific deficiencies observed during an inspection. The notice outlines corrective actions, deadlines and the consequences of non‑compliance. Ship owners must respond promptly to avoid escalation to detention.

Ship‑Specific Training – Training programs designed to address the unique characteristics of a vessel, such as its cargo handling systems, emergency procedures and equipment layout. Ship‑specific training supplements the generic training required by the STCW Convention and is essential for safe operation.

STCW Convention – The International Convention on Standards of Training, Certification and Watchkeeping for Seafarers, which establishes minimum standards for the competence of seafarers. The STCW sets out requirements for basic safety training, certificates of competency, and the periodic renewal of qualifications. The 2010 Manila Amendments introduced new requirements for electronic navigation and fatigue management.

Certificate of Competency – A document issued by the flag state that verifies a seafarer’s qualification to perform a specific watch‑standing role, such as master, chief officer, or marine engineer. The certificate must be presented during inspections and is subject to verification through the IMO’s STCW Database.

Basic Safety Training (BST) – A mandatory training module under STCW that includes fire fighting, elementary first aid, personal survival techniques, and personal safety and social responsibility. BST is required for all seafarers, regardless of rank, and must be refreshed every five years.

Marine Environmental Awareness (MEA) Training – A component of STCW that educates seafarers on the impact of shipping on the marine environment, pollution prevention measures, and the proper handling of hazardous cargoes. MEA training aligns with MARPOL requirements and is part of the basic safety training package.

Bridge Resource Management – A set of procedures and principles that promote effective teamwork, communication and decision‑making on the navigation bridge. BRM is emphasized in STCW training and is essential for preventing human error, which remains a leading cause of maritime accidents.

Fatigue Management – The systematic approach to monitoring and controlling crew work‑rest schedules to prevent fatigue‑related performance degradation. The STCW 2010 amendments introduced specific rest hour requirements, and many flag states now enforce fatigue management plans as part of the Safety Management System.

Ship‑Specific Safety Management System – The documented system that integrates all safety, environmental and operational procedures for a particular vessel. The SMS includes policies for emergency response, maintenance, training, and internal audits. The Safety Management Certificate (SMC) attests that the ship’s SMS complies with the ISM Code.

Safety Management Certificate – The certificate issued to a ship that confirms compliance with the ISM Code. The SMC references the applicable Document of Compliance and must be renewed after successful verification of the ship’s SMS through a flag‑state audit.

Document of Compliance – The certificate issued to a ship‑management company that confirms its SMS complies with the ISM Code. The DOC is valid for five years and is required for every ship managed by the company. The DOC must be displayed on board and is subject to periodic verification.

International Convention on the Control of Harmful Anti‑Fouling Systems on Ships – Commonly known as the AFC Convention, it regulates the use of biocidal paints that may release harmful substances into the marine environment. The convention requires ships to carry an International Anti‑Fouling System Certificate and to ensure that any anti‑fouling product used is approved by the IMO.

International Anti‑Fouling System Certificate – The document that verifies a ship’s compliance with the AFC Convention. The certificate lists the approved anti‑fouling system, its application date and any restrictions. It must be kept on board and presented to port‑state authorities upon request.

Polar Code – The International Code for Ships Operating in Polar Waters, adopted in 2014, which combines safety and environmental provisions for vessels navigating in ice‑covered regions. The Polar Code introduces requirements for hull strength, crew training, and pollution prevention specific to polar conditions. Vessels operating in the Arctic or Antarctic must obtain a Polar Code Certificate.

Polar Code Certificate – The certificate that confirms a ship’s compliance with the Polar Code’s safety and environmental requirements. The certificate is issued by the flag state after verification of design, equipment and crew training. The certificate must be displayed on board and is reviewed periodically.

Ice Class – A classification assigned by a classification society that indicates a ship’s structural strength and capability to operate in ice‑filled waters. Ice classes range from Icebreaker to Ice Class 1A and determine the vessel’s permissible operating limits in polar regions. The Ice Class must be reflected in the ship’s certificates and in the Polar Code compliance documentation.

Ship‑Specific Pollution Prevention Plan – A plan that outlines measures to prevent accidental releases of oil, chemicals, garbage or sewage. The plan includes procedures for containment, response equipment, crew responsibilities and reporting protocols. It is required under MARPOL and is inspected during both flag‑state and port‑state surveys.

Sewage Treatment Plant – Equipment required under MARPOL Annex IV that treats blackwater and greywater to meet discharge standards. The plant must be capable of reducing biological oxygen demand (BOD) and suspended solids to permissible levels before discharge. The plant’s performance is recorded in the Sewage Record Book.

Sewage Record Book – The logbook that documents sewage treatment operations, discharge volumes, and compliance with MARPOL Annex IV. The record book must be kept up to date and be available for inspection. Inaccurate entries can lead to penalties and detention.

Garbage Disposal Facility – Shore‑based infrastructure that receives and processes ship‑generated waste in accordance with MARPOL Annex V. Vessels must verify that the facility is authorized to receive specific waste types before discharging garbage. Failure to use an authorized facility can result in fines and detention.

Air Pollution Control Area – A designated zone where stricter limits on nitrogen oxides (NOx) and sulfur oxides (SOx) emissions are enforced, similar to an Emission Control Area. The IMO has identified several such areas, and ships operating within them must comply with the applicable emission standards, often requiring the use of low‑sulfur fuel or exhaust gas cleaning systems.

NOx Technical Code – The set of technical standards that define the methods for measuring and verifying NOx emissions from marine diesel engines. The code establishes test procedures, engine classification and compliance documentation. Ships must retain NOx compliance certificates and be prepared to present them during inspections.

IMO Ship Identification Number – A unique seven‑digit number assigned to each vessel to facilitate identification and tracking. The number is permanently engraved on the hull and recorded in all official documents. The IMO number remains unchanged throughout the ship’s life, regardless of changes in name, flag or ownership.

Flag‑State Inspection – An inspection conducted by the flag state’s authorized surveyors to verify compliance with international conventions. Flag‑state inspections may be scheduled or unscheduled and typically focus on certification, equipment condition and crew competence. The results are recorded in the ship’s Survey Report.

Survey Report – The document that summarizes the findings of a flag‑state or classification‑society survey. The report includes details of any deficiencies, corrective actions required and the status of certificates. The Survey Report serves as a primary reference for future inspections and for the ship’s maintenance planning.

Ship‑Specific Maintenance Plan – A systematic schedule of preventive maintenance tasks for all critical equipment, including engines, safety systems and navigation aids. The Maintenance Plan is part of the Safety Management System and is audited during ISM Code compliance checks. Proper maintenance reduces the risk of equipment failure and improves overall safety.

Condition Monitoring – The process of continuously tracking the performance of machinery and equipment using sensors, data analysis and predictive algorithms. Condition monitoring helps detect early signs of wear or failure, enabling proactive maintenance. Many modern vessels integrate condition monitoring into their onboard automation systems.

Electronic Engine Monitoring System – A system that records engine parameters such as temperature, pressure, fuel consumption and vibration. The data are stored in the ship’s log and are used for performance analysis, compliance verification and troubleshooting. The system must be calibrated regularly and its data must be retained for a specified period.

Marine Pollution Emergency Response Plan – A comprehensive plan that outlines the coordinated actions to be taken in the event of a pollution incident, such as an oil spill. The plan includes contact information for local authorities, containment measures, cleanup procedures and communication protocols. The plan is required under MARPOL Annex I for oil‑carrying vessels.

Oil Spill Response Vessel – A specialized ship equipped with containment booms, skimmers, dispersants and storage tanks to respond to oil spills. Ports in high‑traffic areas often maintain a fleet of such vessels, and ship owners may be required to contract spill response services as part of their insurance policies.

Marine Insurance – The suite of insurance policies that protect ship owners against liabilities arising from loss of life, cargo damage, pollution and hull damage. Key policies include Protection and Indemnity (P&I) insurance, hull and machinery insurance, and war risk insurance. Insurance terms may be influenced by the vessel’s compliance record and the presence of certificates such as the SMC.

Protection and Indemnity Club – A mutual insurance association that provides P&I coverage to its members. P&I clubs also offer legal assistance, risk management advice and guidance on regulatory compliance. Membership in a P&I club often requires adherence to IMO conventions and evidence of a robust Safety Management System.

Hull and Machinery Insurance – A policy that covers physical damage to the ship’s structure and its mechanical systems. The coverage is contingent on the vessel maintaining valid certificates, undergoing regular surveys and adhering to safety standards. Insurers may impose higher premiums on ships with a history of non‑conformities.

Ship‑Specific Risk Assessment – An analysis that identifies hazards associated with a vessel’s operation, including navigation routes, cargo types, weather conditions and crew competency. The risk assessment informs the development of safety procedures, training programs and emergency response plans. It is a core element of the Safety Management System.

Marine Accident Investigation – The systematic inquiry into the causes of a maritime incident, conducted by the flag state, the ship’s P&I club or an independent authority. The investigation produces a report with findings and recommendations aimed at preventing recurrence. Findings may lead to regulatory changes or the issuance of safety notices.

Safety Notice – A document issued by the IMO or a flag state to disseminate information about a specific safety issue, such as a design flaw, equipment failure or procedural error. Safety notices are intended to alert the maritime community and prompt corrective actions.

Marine Environment Protection Committee – The IMO body responsible for developing and updating environmental conventions, including MARPOL and the BWM Convention. The committee reviews scientific data, industry proposals and member‑state inputs to formulate policies that balance environmental protection with commercial viability.

Committee on Maritime Safety – The IMO body that oversees the development of safety conventions, codes and guidelines. The committee reviews proposals for amendments to SOLAS, the ISM Code and related instruments, and coordinates with other committees to ensure coherence across the regulatory framework.

Marine Technical Committee – The IMO committee that focuses on technical aspects of ship construction, equipment standards and performance criteria. The committee works closely with classification societies to develop guidelines that support the implementation of safety and environmental conventions.

Marine Pollution Prevention Committee – The IMO committee that concentrates on measures to prevent pollution from ships, including oil, chemicals, garbage and air emissions. The committee is responsible for revising MARPOL annexes, developing new protocols and promoting best practices among member states.

International Maritime Satellite Organization – The entity that provides the satellite infrastructure for the GMDSS, including the INMARSAT network. The organization collaborates with the IMO to ensure that satellite services meet the requirements for distress and safety communications.

International Convention on Maritime Search and Rescue – The SAR Convention establishes a global framework for coordinating search and rescue operations at sea. It defines the responsibilities of coastal states, the establishment of rescue coordination centres (RCCs) and the procedures for cooperating with vessels in distress.

Rescue Coordination Centre – A shore‑based facility that receives distress alerts, coordinates search and rescue assets, and communicates with vessels in the area. RCCs operate under the SAR Convention and are integral to the GMDSS network. Effective communication with the RCC is essential for timely rescue operations.

Distress Alert System – The suite of technologies that enable a ship to automatically transmit a distress signal, including the Digital Selective Calling (DSC) function, the Emergency Position Indicating Radio Beacon (EPIRB) and the Search and Rescue Transponder (SART). These devices are required under the GMDSS and must be tested regularly.

Emergency Position Indicating Radio Beacon – A device that, when activated, transmits a distress signal containing the vessel’s identification and position via satellite. EPIRBs are classified as Category I (autonomous) or Category II (manually activated). The beacon’s signal is received by the International Cospas‑Sarsat Programme and routed to the nearest RCC.

Search and Rescue Transponder – A handheld device that responds to radar interrogations by transmitting a coded signal that appears on the radar screen of nearby ships. SARTs are used to locate survivors in the water and are mandatory equipment for vessels operating beyond 12 nautical miles from the nearest shore.

Maritime Labour Convention – Though not an IMO instrument, the MLC 2006 interacts closely with IMO regulations, particularly in the areas of crew welfare, working conditions and certification. The MLC requires ships to maintain a Seafarers’ Employment Agreement, a Ship‑Specific Medical Certificate and to provide adequate living conditions.

Seafarers’ Employment Agreement – A written contract that outlines the terms and conditions of employment for a crew member, including wages, repatriation rights and rest hours. The agreement must be in the seafarer’s native language or in a language they understand, and it is subject to verification during port‑state inspections.

Ship‑Specific Medical Certificate – A certificate issued by a qualified maritime medical practitioner confirming that a seafarer is fit for duty. The certificate must be renewed periodically and is required for all officers and ratings engaged in watch‑standing positions.

Maritime Safety Committee – The IMO body that focuses on the development of safety standards, including the adoption of new technologies, the revision of existing codes and the promotion of best practices. The committee works closely with the Marine Technical Committee to ensure that safety measures are technically feasible.

Ship‑Specific Operational Manual – A manual that provides detailed instructions for the operation of the vessel’s machinery, safety equipment and cargo handling systems. The manual must be kept on board, be readily accessible to the crew and be updated whenever significant changes occur.

Operational Manual – Often referred to as the Ship’s Operating Manual, it encompasses procedures for normal operations, emergency response, maintenance tasks and troubleshooting. The manual is a key component of the Safety Management System and must be reviewed during internal audits.

Internal Audit – A systematic review conducted by the ship‑management company or the ship’s crew to assess compliance with the Safety Management System. Audits evaluate the effectiveness of procedures, the adequacy of training and the implementation of corrective actions. Findings are documented and used to improve safety performance.

Corrective Action – A measure taken to eliminate the causes of a non‑conformity or deficiency identified during an audit or inspection. Corrective actions may involve equipment repair, procedural changes, additional training or documentation updates. They must be recorded in the ship’s audit report and verified for effectiveness.

Preventive Maintenance – Routine tasks performed to keep equipment in optimal condition and to avoid unplanned breakdowns. Preventive maintenance includes lubrication, cleaning, calibration and replacement of wear parts according to the Maintenance Plan. It is a cornerstone of the ISM Code’s emphasis on proactive safety management.

Condition‑Based Maintenance – Maintenance that is triggered by specific indicators, such as vibration levels, temperature thresholds or oil analysis results. Condition‑based maintenance combines real‑time monitoring with predictive analytics to schedule interventions only when necessary, reducing downtime and costs.

Marine Diesel Engine – The primary propulsion system for most commercial vessels. Engines must meet emission standards set by MARPOL Annex VI, including NOx limits defined in the NOx Technical Code. Regular maintenance, fuel quality monitoring and proper engine tuning are essential for compliance.

Turbo‑Charged Engine – An engine equipped with a turbine-driven compressor that increases air intake pressure, improving power output and fuel efficiency. Turbo‑charged engines are common on large container ships and tankers, but they also generate higher exhaust temperatures, requiring robust cooling and emission control systems.

Engine Room – The compartment where the main propulsion machinery, auxiliary generators and related equipment are housed. The engine room must be equipped with fire detection and suppression systems, ventilation, and safe access routes. Access to the engine room is restricted to authorized personnel, and entry procedures are documented in the Safety Management System.

Engine Room Monitoring System – An integrated system that displays real‑time data on engine performance, fuel consumption, exhaust temperature and alarm status. The system provides alarms for abnormal conditions and can be linked to the ship’s automation platform for remote monitoring.

Machinery Space – Any compartment that contains mechanical or electrical equipment, including the engine room, boiler rooms, and cargo pump rooms. Machinery spaces must meet fire safety standards, ventilation requirements and access controls as stipulated by SOLAS.

Fire‑Proof Door – A door with a fire‑resistant rating that helps contain the spread of fire between compartments. Fire‑proof doors must be self‑closing, equipped with appropriate seals, and regularly tested. Their location and operation are documented in the ship’s fire safety plan.

Fire‑Detection System – A network of sensors, alarms and control panels that detect fire or smoke in machinery spaces and accommodation areas. The system may include heat detectors, linear heat sensors, and manual call points. Compliance with SOLAS requires periodic testing and maintenance of the fire‑detection system.

Fire‑Extinguishing System – Fixed installations such as CO₂, foam, or water mist systems that automatically suppress fires in specific compartments. The selection of extinguishing agents depends on the type of fire risk in each area. The system’s performance is verified through regular drills and functional tests.

Life‑Saving Appliance – Any equipment designed to protect lives in emergencies, including lifeboats, life‑rafts, immersion suits, and life‑jackets. Life‑saving appliances must be inspected, serviced and stowed according to SOLAS requirements. The ship’s crew must be proficient in their deployment.

Life‑Saving