Third mate
The third mate, also known as the third officer, is the junior-most licensed deck officer on a merchant vessel or naval auxiliary ship, serving as an Officer in Charge of a Navigational Watch (OICNW) and playing a critical role in ensuring safe navigation, equipment maintenance, and operational compliance.[1][2][3] This position marks the entry-level officer rank for former deck cadets or qualified ratings transitioning to full responsibilities in the deck department, where they support the master and senior officers in bridge operations and vessel management.[2][4] In navigational duties, the third mate stands independent watches on the bridge—typically four hours on and eight off, such as from 0800 to 1200 and 2000 to 2400—monitoring vessel traffic, plotting courses, maintaining charts and equipment, and handling communications like distress alerts via the Global Maritime Distress and Safety System (GMDSS).[1][2] At sea, they act as helmsman when needed and assist in tactical tasks like replenishment or signaling on naval vessels; in port, they oversee cargo loading or unloading, supervise mooring operations, and coordinate with port authorities to ensure security under the International Ship and Port Facility Security (ISPS) Code.[1][3][2] As the designated safety officer on many vessels, the third mate is responsible for inspecting and maintaining lifesaving appliances (LSA) and firefighting equipment (FFE) in compliance with international standards like the International Convention for the Safety of Life at Sea (SOLAS) and U.S. Coast Guard regulations.[1][2] They conduct regular safety drills, update training manuals, manage records of inspections, and operate emergency equipment during incidents, while also handling administrative tasks such as crew documentation, port paperwork, and basic accounting.[1][2][3] Qualifications for the role require certification as an Officer in Charge of a Navigational Watch under the Standards of Training, Certification and Watchkeeping (STCW) Convention, including being at least 18 years old, completing approved maritime education and training, and acquiring sufficient qualified seagoing service (typically at least 36 months in the deck department, with bridge watchkeeping experience).[5] National authorities issue specific licenses, such as the U.S. Coast Guard's Third Mate endorsement, with additional requirements like medical fitness and security clearances varying by flag state and employing fleet.[1][2]Overview
Definition and primary role
The third mate, also known as the third officer, is the junior-most licensed deck officer on merchant vessels, serving as the fourth-in-command after the master, chief mate, and second mate.[6] In this role, the third mate is typically responsible for maintaining the ship's stability through calculations and monitoring, overseeing cargo operations to ensure secure loading and stowage, and coordinating initial emergency responses to maintain safety and operational continuity.[1] These duties position the third mate as a key contributor to the vessel's overall safe navigation and deck management, often including watchkeeping responsibilities under the supervision of senior officers.[3] The role of mates, including junior positions that evolved into the modern third mate, originated in the sailing ship eras of the 17th and 18th centuries, where merchant vessels had hierarchies of mates assisting with navigation, deck supervision, and ship handling. In the modern context, merchant vessels of 500 gross tons or more must have sufficient qualified deck officers, including at least one Officer in Charge of a Navigational Watch (OICNW), as required by the Standards of Training, Certification and Watchkeeping (STCW) Convention, often fulfilled by a third mate on larger ships.[7] This role has adapted to emphasize multitasking in crew-reduced environments, where ongoing automation trends have minimized traditional crew sizes while increasing demands on licensed officers for integrated safety, stability, and cargo oversight. On some vessels without a dedicated doctor, the third mate may be designated as the person in charge of medical care, requiring STCW proficiency in advanced medical care (STCW A-VI/4-2).[8]Position in deck department hierarchy
The third mate, also known as the third officer, occupies the most junior licensed position within the deck department of a merchant vessel, ranking below the captain (master), chief mate, and second mate, while supervising unlicensed deck crew such as able seamen, ordinary seamen, and the bosun.[9][1] As part of the deck department, the third mate reports directly to the second mate and chief mate, assisting in the execution of the master's overall command structure.[1][3] In daily interactions, the third mate supports the chief mate in overseeing deck maintenance and operations, coordinates with unlicensed crew for tasks like cargo handling and equipment upkeep, and stands relief navigational watches to cover for higher-ranking officers during their off-duty periods.[9][3] On smaller vessels with limited crew complements, the third mate's responsibilities may overlap with those of the second mate, including additional bridge duties or cargo supervision to ensure operational efficiency.[1] Vessel type influences the third mate's hierarchical role; on tankers, the position involves heightened oversight of cargo-specific safety protocols and port documentation, integrating closely with the chief mate's cargo management.[9] In contrast, on passenger ships, the third mate's duties may be more distinctly separated from dedicated safety officers, focusing instead on navigational support while safety extends hierarchical responsibilities like equipment inspections.[9][1] In unionized U.S.-flag fleets, third mates operate under defined authority limits established in collective bargaining agreements from the 2010s, such as those negotiated by the American Maritime Officers (AMO) and the International Organization of Masters, Mates & Pilots (MM&P), which outline jurisdictional roles and supervision parameters to maintain clear command chains.[10]Core Responsibilities
Watchkeeping at sea
The third mate, as an officer in charge of a navigational watch at sea, typically stands four-hour shifts, such as from 0800 to 1200 and 2000 to 2400, under the direction of the master to ensure continuous bridge coverage.[2][11] These shifts align with international standards requiring qualified officers to maintain vigilance for safe navigation, with no circumstances permitting the watch officer to leave the bridge until properly relieved.[12] During the watch, the third mate monitors essential equipment including radar, Global Positioning System (GPS), and Automatic Identification System (AIS) to detect potential collisions and track nearby vessels in real time.[2][12] Navigation tasks involve plotting and verifying the ship's course using Electronic Chart Display and Information Systems (ECDIS), which integrate electronic navigational charts with real-time position data to replace traditional paper charts while ensuring compliance with safety settings like under-keel clearance contours.[2][13] The officer also adjusts the vessel's heading and speed based on weather conditions, using instruments such as anemometers for wind speed and barometers for atmospheric pressure to anticipate changes in sea state or visibility.[2] All actions must adhere to the International Regulations for Preventing Collisions at Sea (COLREGS), including determining right-of-way rules and taking early, decisive maneuvers to avoid close-quarters situations.[12] In managing maritime traffic, the third mate handles vessel encounters by assessing relative bearings and courses, particularly in high-traffic areas such as the Strait of Malacca or Dover Strait, where vessel density requires heightened vigilance.[2][12] Communications via Very High Frequency (VHF) radio are essential for coordinating with other ships, relaying intentions, and confirming avoidance actions in accordance with COLREGS Rule 2.[2] A continuous proper look-out is maintained, often supplemented by additional personnel in congested waters, to detect hazards beyond electronic aids.[12] Should any irregularity arise, such as equipment malfunction or imminent danger, the third mate immediately notifies the master and, if necessary, initiates emergency procedures to safeguard the vessel and crew.[12]Watchkeeping in port
When a vessel is anchored or docked, the third mate typically stands port watches on a schedule of two 6-hour shifts, such as 0600–1200 and 1800–2400 hours, or as assigned by the chief mate or master, allowing for continuous oversight of stationary operations.[2] These shifts emphasize security patrols around the deck and gangway to deter unauthorized access, as well as regular inspections of mooring lines for signs of wear, tension, or chafing to maintain vessel stability against tidal changes or weather.[14] The third mate communicates findings to the bridge team and coordinates adjustments, such as tightening or replacing lines, ensuring compliance with mooring equipment guidelines.[2] A core aspect of in-port watchkeeping involves supervising cargo handling operations, including the loading and unloading of goods via cranes, pumps, or conveyor systems, to prevent damage and ensure efficient stowage.[1] The third mate oversees deck crew in securing cargo, monitors ballasting and deballasting to adjust trim and list, and verifies that operations align with the vessel's stability criteria derived from prior inclining experiments, which establish baseline metacentric height for safe loading limits.[2] This includes real-time checks on ship stress levels using monitoring software or draft surveys, halting activities if stability falls below approved thresholds to avoid risks like excessive heel or shear forces.[1] In port-specific maneuvers, the third mate coordinates with harbor pilots and tug operators during berthing or unberthing, often managing the aft mooring station to relay line-handling instructions via radio and ensure safe alignment with the dock.[2] Additionally, during bunkering— the transfer of fuel or lubricants—the third mate monitors deck connections and spill containment measures, such as scupper plugs and drip trays, to mitigate pollution risks from overflows or leaks, reporting any incidents immediately to port authorities in line with MARPOL regulations.[2] Under the International Ship and Port Facility Security (ISPS) Code, implemented in 2004, the third mate contributes to ship security by conducting access control at entry points, verifying visitor identifications, and logging movements to prevent unauthorized boarding.[15] In high-risk ports, such as those in Southeast Asia prone to piracy threats, this extends to leading anti-piracy drills, including perimeter patrols and activation of citadel protocols, as outlined in the vessel's Ship Security Plan.[16] These measures enhance overall safety protocols without overlapping with dedicated environmental officer roles.[2]Safety and environmental officer duties
The third mate is frequently designated as the ship's safety officer under the International Safety Management (ISM) Code, which mandates the establishment of a safety management system to ensure safe operations and pollution prevention.[17] In this capacity, the third mate prepares and maintains muster lists outlining crew assignments for emergencies, oversees the routine maintenance and inventory of firefighting gear such as hoses, nozzles, and breathing apparatus, and conducts inspections of lifeboats and other life-saving appliances to verify operational readiness.[2] These responsibilities align with the ISM Code's emphasis on defined roles within the company's safety management system, ensuring equipment compliance with international standards.[17] In emergency management, the third mate leads the organization and execution of abandon-ship drills, scheduling them according to the vessel's drill matrix and confirming post-drill functionality of equipment like self-contained breathing apparatus.[2] They also coordinate crew training on man-overboard procedures, which include deploying lifebuoys, marking the position, and utilizing tools such as thermal imaging cameras to locate individuals in low-visibility conditions during search efforts.[18] These drills integrate with routine watchkeeping by incorporating safety checks, such as verifying emergency signals and crew response times.[2] On the environmental front, the third mate ensures compliance with the International Convention for the Prevention of Pollution from Ships (MARPOL), particularly Annex I provisions for oil spill prevention, by supervising cargo and ballast operations to avoid unauthorized discharges.[19] This includes monitoring oil transfer records and implementing spill response protocols.[2] Additionally, they oversee ballast water management under the Ballast Water Management (BWM) Convention, which entered into force in 2017 with phased implementation of stricter discharge standards (D-2) through the 2020s, requiring treatment systems to minimize the transfer of harmful aquatic organisms.[20] The third mate maintains the ballast water record book and ensures adherence to exchange or treatment procedures during voyages.[21]Training and Certification
International standards (STCW)
The International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW), originally adopted in 1978 and substantially revised by the 2010 Manila Amendments, sets the minimum international requirements for the training, certification, and watchkeeping duties of third mates, who function as Officers in Charge of a Navigational Watch (OICNW) on vessels of 500 gross tonnage or more engaged in international voyages.[5] These standards ensure that officers possess the necessary competencies to safely navigate ships, maintain watch, and respond to emergencies, with certifications issued by flag states upon verification of compliance.[5] Under STCW Regulation II/1 and Table A-II/1 of the STCW Code, candidates for OICNW certification must be at least 18 years of age and demonstrate at least 12 months of approved seagoing service in the deck department on appropriate vessels, including a minimum of six months of bridge watchkeeping under the direct supervision of a qualified officer.[22] This service requirement may be fulfilled through an integrated approved training program that incorporates practical experience and simulator-based exercises to simulate real-world navigational scenarios.[22] Approved education and training programs must also cover mandatory basic safety training, including personal survival techniques, fire prevention and firefighting, elementary first aid, and personal safety and social responsibilities.[5] Core competencies for third mates emphasize navigational proficiency, such as using radar for observation and plotting to assess collision risks, as well as understanding ship stability to prevent capsizing, including calculations of the metacentric height via the formulaGM = KM - KG
where GM is the metacentric height, KM is the distance from the keel to the metacenter, and KG is the vertical position of the center of gravity above the keel; this ensures the vessel's righting ability in various loading conditions.[23] Additional requirements include basic firefighting skills, such as using portable extinguishers and fixed systems to control outbreaks on board.[5] These elements are assessed through examinations, practical demonstrations, and documented training records to confirm operational readiness.[22] The 2010 Manila Amendments strengthened these standards by mandating enhanced training in areas like electronic chart display and information systems (ECDIS), leadership and teamwork, and engine-room resource management, with full implementation required by 2012.[5] Further updates in the 2025 STCW supplement introduce provisions for electronic issuance and verification of certificates, facilitating digital management while maintaining security and authenticity.[24] Complementing STCW, the International Labour Organization's Maritime Labour Convention (MLC) 2006 integrates fatigue management into third mate training by limiting maximum working hours to 14 per day and requiring at least 10 hours of rest in any 24-hour period, or 77 hours in any seven-day period, with records maintained to prevent watchkeeping errors due to exhaustion.[25] National pathways may adapt these STCW baselines to include additional assessments or sea time equivalents.[5]