SOLASStudy notes

Comprehensive Analysis of the SOLAS Convention and Mandatory Amendments:

The Structural and Evolutionary Framework of SOLAS

The International Convention for the Safety of Life at Sea (SOLAS) represents the primary regulatory pillar of international maritime safety, standing alongside MARPOL and STCW as the core legislative framework governing global shipping¹. First adopted in 1914 in the wake of the Titanic disaster, the convention has evolved through successive iterations to its current form, the SOLAS 1974 Convention¹. The longevity and adaptability of this version are primarily due to the "tacit amendment procedure" established under Article VIII³. Under this mechanism, technical amendments adopted by the Maritime Safety Committee (MSC) automatically enter into force on a specified date unless actively rejected by more than one-third of Contracting Governments, or by Contracting Governments representing at least fifty percent of the world's gross merchant tonnage³.

For a Marine Engineering Officer (MEO) Class 1 candidate, the oral examination demands a rigorous, operationally focused understanding of these regulations. On board, the Chief Engineer is responsible for the safe operation, maintenance and readiness of machinery and engineering systems under his or her charge, while statutory SOLAS compliance is ultimately implemented through the Company and verified by the Flag Administration or its Recognized Organization. The Chief Engineer must therefore ensure that engineering systems, records, tests and maintenance under the department remain compliant and immediately report defects affecting seaworthiness or statutory compliance to the Master and Company.

Chapter I: General Provisions and the Harmonized Survey Regime

SOLAS Chapter I establishes the administrative foundation of the convention, detailing the scope of application, survey methodologies, and the certification structure that validates a vessel's compliance with international safety standards⁸. The chapter applies to all passenger ships and cargo ships of 500 gross tonnage (GT) and upwards engaged on international voyages, while explicitly excluding warships, wooden ships of primitive build, fishing vessels, and non-propelled craft⁸.

The administrative framework is governed by the Harmonized System of Survey and Certification (HSSC), which standardizes the validity periods and survey windows of the major international certificates¹². The HSSC enables shipowners to streamline operational schedules by aligning survey dates, reducing dry-docking frequency, and minimizing administrative costs².

The HSSC mandates a minimum of two inspections of the outside of the ship's bottom during any five-year validity cycle of the SAFCON or CARSAF certificate¹². The maximum interval between any two consecutive bottom inspections must not exceed 36 months¹². Under HSSC rules, a standard renewal survey may be completed within three months prior to the expiry date of the existing certificate without altering the original anniversary date¹².

If a vessel is not in port when its certificate expires, the flag Administration may grant an extension for up to three months to allow the vessel to complete its voyage to a port of survey¹². For ships engaged on short voyages, a one-month grace period may be granted¹². When an extension is utilized, the new certificate dates its five-year validity cycle from the original expiry date before the extension was applied¹². Original statutory certificates must be kept on board and be available for Port State Control (PSC) inspections at all times, though modern provisions allow for verified electronic certificates featuring unique tracking numbers and QR codes for digital validation⁸.

Chapter II-1: Engineering Systems, Machinery, and Watertight Integrity

Critical Systems and Emergency Electrical Power (Regulations 42 and 43)

SOLAS Chapter II-1 governs the structural, subdivision, stability, and machinery standards of the vessel, focusing heavily on engineering redundancy to prevent a total loss of power or steering capability⁸. The regulations distinguish between the emergency electrical requirements of passenger ships (Regulation 42) and cargo ships (Regulation 43), with both demanding a self-contained emergency source of power located above the bulkhead deck, aft of the collision bulkhead, and entirely outside the Category A machinery boundaries¹⁸.

+-----------------------------------------------------------------+
| EMERGENCY SWITCHBOARD (ESB) |
+-----------------------------------------------------------------+
|
+------------------------+------------------------+
| |
+--------------+ +--------------+
| TRANSIENT | | EMERGENCY |
| BATTERY | | GENERATOR |
| (30 Minutes) | | (18/36 Hrs) |
+--------------+ +--------------+
| |
+-------------> [ Critical Emergency Loads ] <-----+

The emergency power source must be either an accumulator battery bank or a diesel generator set¹⁸. The emergency generator must start automatically and come on-load within 45 seconds of a main power failure¹⁹. The starting arrangements must feature a primary and a secondary mode of stored energy²¹. The primary starting mode (typically electric start batteries) must be capable of providing three consecutive starts²¹.

The secondary starting mode (such as hydraulic starters or hand-cranked spring starters) must provide an additional three starts within 30 minutes²¹. The diesel prime mover must be capable of cold-starting at , with thermostatically controlled heating jackets required if the vessel operates in sub-zero regions²¹. Furthermore, the emergency generator must remain fully operational when the vessel is listed up to or trimmed to simultaneously²¹.

The transitional source of emergency power, consisting of batteries, must supply key services for 30 minutes during the 45-second start-up period¹⁹. These services include emergency lighting at all muster and embarkation stations, navigation lights, internal communication networks, fire detection alarms, GMDSS radio equipment, and the steering gear control loops¹⁹.

For cargo ships, SOLAS II-1/43 generally requires the emergency source of electrical power to be capable of supplying the specified emergency services for 18 hours. Passenger ships are generally subject to the 36-hour duration in SOLAS II-1/42. The exact emergency loads are those listed in the applicable regulation and should not be reduced to a generic list; they include essential emergency lighting, communications, navigation, fire-detection/alarm and other specified safety services.

Steering Gear Redundancy and Safety Systems (Regulations 29 and 30)

The steering gear must be configured to guarantee maneuverability under all service conditions²³. SOLAS mandates that every ship be equipped with a main steering gear and an auxiliary steering gear²³.

If a vessel is equipped with duplicate, identical steering gear power units, the auxiliary steering gear is not required, provided that the main steering system is arranged such that a single failure in its piping or power units can be isolated and steering regained²³. For tankers, chemical tankers, or gas carriers of 10,000 GT and upwards, the steering system must regain full steering capability within 45 seconds of a single failure in any part of the active piping system or power units²³.

For all other ships of 70,000 GT and upwards, the main steering gear must feature an automatic leak detection, isolation, and changeover system to isolate hydraulic leaks and maintain directional control²⁷.

From an electrical perspective, steering gear feeder circuits must have short-circuit protection and an overload alarm only²¹. Traditional overload thermal trips are prohibited; if a steering motor overheats during a navigation emergency, the motor must be run to destruction rather than tripping and disabling the rudder²¹. Feeder cables must be routed along separate paths to prevent a single localized fire from disabling both steering motor power lines²³.

Hydraulic systems must have low-level fluid alarms on the bridge and in the engine control room, and a permanent, dedicated storage tank must be installed in the steering flat to allow the rapid replenishment of at least one complete hydraulic system in a single operation²³.

Engine Room Bilge Pumping Systems (Regulation 35-1)

Bilge pumping systems are designed to preserve ship stability by draining watertight machinery and cargo compartments during normal operations or following a hull breach³⁰. The system must operate under all practical casualty conditions, whether the vessel is upright or listed³⁰.

Cargo ships are required to have an efficient bilge pumping system with at least two power pumps connected to the main bilge system, subject to the detailed SOLAS II-1/35-1 requirements and approved ship arrangement. Passenger-ship bilge pumping requirements are more extensive and depend on the applicable subdivision standard and ship arrangement; they should not be memorized as a universal 'three pumps including one submersible emergency pump' rule. Bilge, ballast and sea-water systems may have approved cross-connections, but arrangements must prevent inadvertent flooding or backflow.

In machinery spaces, SOLAS requires an emergency bilge suction arrangement capable of dealing with serious flooding. The suction is connected to a suitable independent power pump of adequate capacity in accordance with the approved design; the specific pump used varies from ship to ship and should not be stated universally as the main seawater circulating pump. The emergency suction should lead to a readily accessible low point in the machinery-space bilge and be arranged to avoid accidental admission of sea water.

The control valve for this suction must be a non-return type with its spindle extended above the engine room floor plates, enabling immediate manual override³⁰. To ensure structural integrity in high-temperature scenarios, all bilge pipes used in or under fuel storage tanks, or within machinery spaces, must be constructed of heavy-gauge steel or another fire-resistant material³².

Mooring and Lifting Regulations (Regulations 3-8 and 3-13)

SOLAS Chapter II-1 has been revised to address operational risks associated with mooring lines, anchor winches, and cargo gear³⁴.

•Towing and Mooring Equipment (Regulation II-1/3-8): The revised SOLAS requirements and associated IMO guidelines strengthen the design, inspection and maintenance of towing and mooring equipment. New-ship design requirements are linked to the ship's construction date, while all applicable ships must maintain mooring equipment, lines and fittings in a safe condition using documented inspection and maintenance procedures. Mooring fittings are to be marked in accordance with the applicable design/maintenance requirements and the ship's mooring arrangement documentation. Avoid treating 'all ships built after 2007 must carry an MSMP' as the SOLAS rule; applicability and documentation follow regulation II-1/3-8 and MSC.1/Circ.1619/1620 series guidance.

•Lifting Appliances and Anchor Handling Winches (Regulation II-1/3-13): In force from 1 January 2026. Lifting appliances installed on or after that date must be designed, constructed and installed to recognized classification-society requirements or equivalent standards accepted by the Administration, and load-tested/thoroughly examined before first use and after major repairs or alterations. Existing lifting appliances and anchor handling winches installed before 1 January 2026 must be tested and thoroughly examined no later than the first renewal survey on or after 1 January 2026. All covered lifting appliances, anchor handling winches and loose gear, regardless of installation date, are subject to operational testing, thorough examination, inspection, operation and maintenance under IMO guidance. Specific exemptions in regulation II-1/3-13 must also be checked.

Chapter II-2: Fire Protection, Detection, and Extinction

Emergency Boundary Systems and Fire Mains (Regulation 10)

Chapter II-2 establishes the design, isolation, and suppression standards needed to contain fires within the space of origin³. The regulations divide the vessel into main vertical and horizontal zones using thermal and structural boundaries, such as Class A, B, and C fire-rated bulkheads³.

The emergency fire pump represents a critical line of defense, ensuring that fire main pressure is maintained even if a fire in the main machinery space disables the primary fire pumps³⁹. The emergency pump, its diesel engine driver, its fuel supply tank, and its starting battery must be located entirely outside the Category A machinery space²¹.

Emergency fire-pump requirements depend on ship type, gross tonnage and the applicable SOLAS II-2/10 provisions. The pump must be independent of a machinery-space fire that could disable the main fire pumps and must have an approved independent sea suction. For cargo ships, the capacity is not less than 40% of the total required capacity of the fire pumps and in any case not less than 25 m³/h. Installation details, suction performance and accessibility must comply with the approved arrangement; do not quote a universal 4.5 m suction-head limit for every ship without checking the applicable requirement and design standard.

The fire-main pressure and nozzle requirements vary with ship type and gross tonnage. The system must be capable of producing at least two required jets of water simultaneously from separate hydrants. Nozzle diameters are selected from the SOLAS-permitted standard sizes (normally 12 mm, 16 mm and 19 mm, or as near as possible) according to space and duty; 12 mm is not a universal machinery-space nozzle size. For oral examination, quote the pressure/capacity applicable to the ship category asked by the surveyor.

Isolating valves must separate the section of the fire main within the machinery space from the rest of the vessel's fire main³⁹. These valves must be located in an easily accessible position outside the machinery space, ensuring that if the internal fire main is ruptured, the external hydrants can still be pressurized³⁹.

Fixed Gas Fire-Extinguishing Systems (Regulation 10)

The design, storage, and discharge of fixed high-pressure Carbon Dioxide () systems are strictly regulated to ensure rapid fire suppression while safeguarding the crew²¹.

•Discharge and Capacity: The fixed system must discharge at least of the required volume of gas directly into the protected machinery space within of activation to rapidly smother the fire²¹.

•CO₂ Storage Room: Cylinders and release equipment must be arranged in accordance with SOLAS II-2 and the FSS Code. Storage spaces outside the protected space must be safely located, readily accessible, effectively ventilated and arranged so that leakage cannot endanger personnel. Where below deck, access and ventilation arrangements must meet the FSS Code. Do not quote '55°C maximum room temperature' as a universal SOLAS requirement; cylinder temperature limits follow the approved system and pressure-vessel specification.

•Release Controls: Fixed gas systems protecting normally occupied spaces require a suitable pre-discharge audible alarm and sufficient time for evacuation before release. CO₂ systems are arranged so that the release cannot occur by a single inadvertent action; the control arrangement normally requires two separate actions. Ventilation, openings, fuel supply and machinery shutdowns necessary to retain the extinguishing medium must be capable of being closed/stopped from safe positions, but opening a release cabinet should not be memorized as a universal automatic ventilation-shutdown rule.

Mandatory Fuel Oil Safety Declarations (Regulation 4)

Amendments in force from 1 January 2026 strengthen control of fuel oil supplied for use on board in relation to the SOLAS minimum flashpoint requirement of 60°C.

Before bunkering, the fuel supplier must provide a signed declaration that the fuel oil complies with SOLAS II-2/4.2.1 and state the test method used. The bunker documentation is to provide the flashpoint information required by the amended regulation. For oral examination, remember the SOLAS minimum flashpoint for fuel oil used on board is 60°C unless a specific permitted exception applies.

Contracting Governments are required to take appropriate action on confirmed cases of fuel oil supplied below the SOLAS flashpoint requirement and report as required through the IMO framework.

Fluorinated Foam Bans (Regulation 10.2.1)

To address the environmental and biological toxicity of bioaccumulative chemicals, IMO Resolution MSC.532(107) bans fire-fighting foams containing Perfluorooctane Sulfonic Acid (PFOS)⁴².

•Application Timelines: Ships constructed on or after 1 January 2026 are prohibited from carrying or using any fire-extinguishing media containing PFOS upon delivery⁴⁴. Vessels constructed before 1 January 2026 must replace PFOS-containing foams no later than the first scheduled safety equipment (SEQ) survey on or after 1 January 2026⁴⁴.

•PFOS prohibition: SOLAS II-2/10.11 prohibits the use or storage of fire-extinguishing media containing perfluorooctane sulfonic acid (PFOS). For ships constructed before 1 January 2026, compliance is required not later than the first survey on or after 1 January 2026. For oral examination, state the prohibition itself rather than relying on a concentration threshold as the primary rule.

•Disposal Regulations: Prohibited PFOS media must be delivered to an approved shore-based reception facility, and the removal and disposal must be logged in the ship's official logbook⁴⁴. System tanks and lines must be thoroughly flushed and cleaned before introducing compliant replacement foam⁴⁴.

Chapter III: Life-Saving Appliances and Arrangements

Chapter III and the associated Life-Saving Appliance (LSA) Code govern the design, capacity, and operational readiness of survival craft, rescue boats, and personal life-saving equipment².

Mechanical Ventilation of Enclosed Lifeboats

Following studies indicating high levels of carbon dioxide () accumulation and severe heat stress inside sealed lifeboats, the IMO adopted Resolution MSC.535(107), establishing new ventilation standards for totally enclosed lifeboats⁴⁵.

The amendments require totally enclosed lifeboats to provide a ventilation rate of at least per person for the maximum number of survivors the craft is certified to accommodate⁴. This ventilation must operate continuously for at least ⁴.

If the ventilation system is power-driven, the electrical source must not be the primary radio batteries⁵. If powered by the lifeboat engine, the fuel tank capacity must support both propulsion and continuous ventilation system operation⁵.

The system must not compromise the lifeboat's self-righting capability⁴⁵. Air intake and exhaust openings must be fitted with manual closing valves that can be operated from inside the cabin, and positioned to minimize water ingress during launching⁵.

The regulation enters into force on 1 January 2026 and applies to all totally enclosed lifeboats installed on or after 1 January 2029⁴.

Survival Craft Launching and Test Protocols

SOLAS Chapter III requires rigorous operational testing to ensure survival craft can be launched safely in an emergency⁹. Under Regulation 33, launching appliances for survival craft on cargo ships of 20,000 GT and upwards must be capable of launching lifeboats when the ship is making headway at speeds up to 5 knots in calm water⁹. This headway-launching capability must be verified during initial surveys and subsequent dry-docking periods⁹.

Furthermore, free-fall lifeboat release systems must undergo operational testing every five years under a load of 1.1 times the total mass of the lifeboat⁴⁸. This test can be conducted either by a physical free-fall launch with only the operating crew on board, or by a simulated launch in accordance with IMO guidelines⁴⁸.

The minimum lowering speed for fully loaded survival craft and rescue boats is calculated using the formula:

where is the lowering speed in meters per second, and is the height in meters from the davit head to the waterline when the ship is in its lightest seagoing condition⁴⁵.

This formula ensures that lifeboats are lowered quickly enough to prevent them from swinging back against the ship's side in heavy seas, while maintaining a safe maximum speed to prevent deceleration forces from injuring survivors upon water impact⁴⁵.

Chapter IV: Radiocommunications and GMDSS Modernization

Chapter IV regulates the equipment, watchkeeping, and reserve power sources for the Global Maritime Distress and Safety System (GMDSS)³⁸.

GMDSS Modernization Framework

Amendments that entered into force on 1 January 2024 modernized Chapter IV by introducing updated equipment standards and removing obsolete technologies⁹.

+-----------------------------------------------------------------+
| GMDSS POWER SOURCES |
+-----------------------------------------------------------------+
|
+------------------------+------------------------+
| |
+--------------+ +--------------+
| MAIN POWER | | EMERGENCY S/B|
| (Generators) | | (Gen/Battery)|
+--------------+ +--------------+
| |
+-------------> [ GMDSS Distribution Board ] <----+
|
+-----------+-----------+
| |
+-----------+ +-----------+
| MF/HF | | VHF/DSC |
+-----------+ +-----------+

The 2024 amendments relocated several key communication requirements⁹. The rules for two-way VHF radiotelephones, Search and Rescue Transponders (SART), and AIS-SARTs were transferred from Chapter III (Regulation 6) to Chapter IV (Regulation 7) to consolidate all communication gear under a single administrative chapter⁴⁹.

The definition of Sea Area A3 was also updated⁴⁹. It is no longer defined strictly by the range of an Inmarsat geostationary satellite, but is now based on the range of any Recognized Mobile Satellite Service (RMSS) carried on board⁴⁹.

This allows alternative satellite systems, such as Iridium, to be used to satisfy A3 carriage requirements⁴⁹. Under these modernized rules, the primary radio installations for vessels navigating in Sea Area A3 are MF (Medium Frequency) and an approved RMSS, and the requirement for obsolete MF/HF Narrow-Band Direct-Printing (NBDP) radiocommunication has been removed⁴⁹.

GMDSS Reserve Power Sources (Regulation 13)

The GMDSS radio station must have a reliable reserve source of energy, typically an accumulator battery bank, to power distress communications if the ship's main and emergency generators fail²².

•Reserve Battery Capacity: If the vessel is equipped with an emergency generator that complies with SOLAS Chapter II-1, the GMDSS reserve batteries must be capable of powering the radio installations for at least 1 hour²². If the vessel does not carry a compliant emergency generator, the GMDSS batteries must power the radio equipment for at least 6 hours²².

•Charge Requirements: The battery charger must be capable of fully recharging the GMDSS batteries to their minimum required capacity within 10 hours⁵⁰.

•Discharge and Voltage Tolerances: The batteries must be designed so that the voltage does not drop by more than of their nominal rating during full discharge²². Battery capacity must be verified at least once every 12 months using a controlled discharge test⁵⁰.

Electronic Inclinometers (SOLAS V/19): From 1 January 2026, containerships and bulk carriers of 3,000 GT and upwards constructed on or after that date must be fitted with an electronic inclinometer, or other means, to determine, display and record the ship's roll motion. The requirement does not apply to cargo ships only occasionally carrying cargoes in bulk or general cargo ships carrying containers on deck. SOLAS does not simply state that the inclinometer must be connected directly to the VDR; the mandatory function is to determine, display and record roll motion.

Chapter V: Safety of Navigation

Chapter V outlines the operational bridge procedures, voyage planning requirements, and bridge equipment standards applicable to all vessels⁸.

Bridge Equipment and Electronic Inclinometers (Regulation 19)

Pilot Transfer Arrangements (SOLAS V/23): Amendments adopted at MSC 110 are scheduled to enter into force on 1 January 2028. They introduce mandatory performance standards covering design, manufacture, construction, installation, inspection, stowage, maintenance, replacement and familiarization, prohibit mechanical pilot hoists and require adequate lighting. Transitional application is phased; avoid stating a blanket rule that every existing ship must replace its arrangement at the first renewal survey without checking the adopted transitional provisions.

To prevent cargo shifts, parametric rolling, and structural damage on large container ships and bulk carriers, a new amendment entering into force on 1 January 2026 mandates the installation of electronic inclinometers⁴⁴. All container vessels and bulk carriers of 3,000 GT and upwards constructed on or after 1 January 2026 must carry a certified electronic inclinometer⁴⁴.

This system must measure and display the vessel's angle of heel and roll period⁴⁴. The inclinometer must be connected directly to the Voyage Data Recorder (VDR) to allow roll profiles to be reconstructed during accident investigations⁴⁴.

Pilot Transfer Arrangements (Regulation 23)

Pilot boarding arrangements are subject to regular safety updates due to the persistent risk of falls during embarkation⁵².

Amendments entering into force on 1 January 2028 revise the technical construction and inspection standards of pilot ladders and associated winches⁵². All vessels of 150 GT and upwards constructed on or after 1 January 2028 must carry certified pilot ladders that comply with strict ISO standards, and existing ships must replace non-compliant boarding arrangements at their first scheduled renewal survey after that date⁵².

Pre-Departure Steering Tests and Drills (Regulation 26)

Regulation 26 mandates a strict testing and drill schedule to ensure the steering gear is fully operational before a vessel maneuvers in congested waters²⁶.

•Pre-Departure Test (The 12-Hour Rule): Within 12 hours prior to departure, the ship's crew must test the steering gear system²⁶. This test includes verifying the full movement of the rudder, the operation of all remote steering control systems from each bridge position, the emergency power supply connections, the accuracy of the rudder angle indicators against the actual rudder position, the operation of all power failure and control alarms, and the functionality of the automatic isolating arrangements²⁶.

•Emergency Steering Drills: Emergency steering drills must be conducted at least once every three months²⁶. These drills must practice direct manual control from inside the steering gear compartment, using local hydraulic valves²⁶. The drill must verify the communication links between the steering flat and the bridge (using sound-powered telephones or dedicated VHF headsets), the operation of alternative power supplies, and crew familiarization with the changeover procedures²⁶. All tests and drills must be recorded in the ship's official logbook⁵⁴.

Chapter VI: Carriage of Cargoes and Oil Fuels

Chapter VI regulates the safe cargo stowage, securing, and environmental management of all cargoes except bulk liquids and gases⁸.

The regulations require all vessels carrying dry or unitized cargoes to carry an approved Cargo Securing Manual (CSM)⁸. The CSM must be compiled in accordance with IMO guidelines, detailing the lashings, points of attachment, and maximum deck loads allowed⁸.

Under Regulation 5-2, which applies to all tankers, the blending of bulk liquid cargoes at sea during voyages is prohibited⁴⁸. This rule prevents the chemical alteration of petroleum products or biofuels outside the safety controls of a port terminal, reducing the risk of vapor ignition or toxic gas release⁴⁸.

For vessels carrying grain, Chapter VI mandates compliance with the International Grain Code¹. Amendments entering into force on 1 January 2026 introduce updated cargo-loading parameters, allowing vessels to utilize a newly defined optional loading condition: "specially suitable compartment, partly filled in way of the hatch opening, with ends untrimmed"⁴².

Vessels wishing to load grain under this optional condition must update their approved grain loading manual and submit it to their flag Administration or Recognized Organization for review⁴².

Chapter VII: Carriage of Dangerous Goods

IMDG Code: For 2026 preparation, use IMDG Code Amendment 42-24, which became mandatory on 1 January 2026. It updates dangerous-goods provisions in line with the UN Recommendations and supersedes Amendment 41-22 as the current mandatory edition for ships carrying dangerous goods in packaged form.

The chapter mandates compliance with the International Maritime Dangerous Goods (IMDG) Code, the International Bulk Chemical (IBC) Code, and the International Gas Carrier (IGC) Code¹. Recent amendments to the IMDG Code (such as Amendment 41-22) align marine transport rules with the UN Recommendations on the Transport of Dangerous Goods, introducing updated requirements for fiber-reinforced plastic (FRP) portable tanks and pressure receptacle markings⁵⁹.

For chemical and gas tankers, amendments to the IBC and IGC Codes introduce provisions for using toxic or low-flashpoint cargoes as fuel⁹. To facilitate the transition to alternative marine fuels like ammonia and hydrogen, these amendments establish safety criteria for engine rooms and fuel piping on gas carriers⁶⁰.

Furthermore, IGC Code revisions regulate watertight doors on gas carriers, aligning damage stability rules with those of standard cargo tankers⁹.

Chapter VIII: Nuclear Ships

Chapter VIII outlines the special safety, radiation protection, and operational requirements for nuclear-powered merchant ships⁸.

The regulations apply to all nuclear ships, requiring them to carry a Safety Assessment containing detailed analysis of the nuclear power plant, shielding, and potential radiation hazards⁸. This assessment must be submitted to the host administration of any port the vessel intends to visit⁸.

Nuclear vessels must be issued a Nuclear Passenger Ship Safety Certificate or a Nuclear Cargo Ship Safety Certificate, verifying that the reactor and structural containment comply with strict safety criteria⁸.

While few nuclear-powered merchant ships operate today, these regulations remain in force to provide a legal framework for potential future reactor technologies³.

Chapter IX: Management for the Safe Operation of Ships and the ISM Code

Chapter IX mandates compliance with the International Safety Management (ISM) Code, which establishes shipboard and company safety management systems (SMS)².

Audit Framework and Certificate Validity

The SMS must define safety policies, establish lines of communication, designate a shore-side contact (the Designated Person Ashore, DPA), and provide instructions for emergency response and preventive maintenance⁶.

+-----------------------------------------------------------------+
| ISM AUDIT TIMELINES |
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|
+------------------------+------------------------+
| |
+--------------+ +--------------+
| COMPANY DOC | | VESSEL SMC |
| (5 Years) | | (5 Years) |
+--------------+ +--------------+
| |
[ ANNUAL ] [ INTERMEDIATE ]
(Window: +/- 3M) (Between Yr 2-3)

The Document of Compliance (DOC) is issued to the operating company following a successful audit of its shore-side offices⁶². The DOC is valid for 5 years, subject to annual verification audits held within three months of its anniversary date⁶².

The Safety Management Certificate (SMC) is issued to each individual vessel⁶². The SMC is valid for 5 years, subject to an intermediate verification audit conducted between the second and third anniversary dates⁶².

The SMS requires the company to conduct internal audits of its offices and vessels at intervals not exceeding 12 months⁶³.

Classification of Audit Findings and MNC Actions

During external or internal audits, surveyors may issue findings classified under three distinct severity levels⁶².

•Observation: A statement of fact substantiated by objective evidence⁶². It identifies a minor safety management weakness that, if uncorrected, could lead to a non-conformity⁶².

•Non-Conformity: An observed situation where objective evidence indicates the non-fulfillment of a specific safety management or statutory requirement⁶².

•Major Non-Conformity (MNC): An identifiable deviation that poses a serious and immediate threat to the safety of personnel, the ship, or the environment, or represents a systemic failure to implement a mandatory requirement of the ISM Code⁶².

A Major Non-Conformity (MNC) under the ISM Code is a serious deviation that poses a serious threat to personnel or ship safety or a serious risk to the environment and requires immediate corrective action, or indicates a lack of effective and systematic implementation of the ISM Code. An MNC requires prompt action by the Company and Administration/RO and may lead to withdrawal or suspension of certification if not satisfactorily addressed. It should not be stated that every MNC automatically equals statutory detention or automatic SMC suspension at the moment it is raised.

The immediate priority after an MNC is to remove or control the serious risk and demonstrate effective corrective action to the auditor/Administration. Depending on the verification procedure, additional verification may be required before the certificate can remain valid or be restored. The practical outcome depends on the nature of the MNC and the Administration/RO decision; there is no universal rule that it must first be 'downgraded to a minor NC' before the vessel can sail.

Permanent corrective and preventive actions must then address the root cause and be verified within the period specified by the Administration/RO under the ISM certification procedure. Do not memorize a universal 'maximum three months for every MNC' rule; the applicable verification and certification instructions govern the close-out period.

Chapter X: Safety Measures for High-Speed Craft

Chapter X mandates compliance with the International Code of Safety for High-Speed Craft (HSC Code), which regulates the design, construction, and equipment of high-speed passenger and cargo vessels².

The chapter requires all high-speed craft to hold a High-Speed Craft Safety Certificate, verifying compliance with the 1994 or 2000 HSC Codes¹. These vessels are subject to strict structural weight and stability limits to ensure safe operation at high speeds⁸.

Recent amendments to the HSC Code align its communication and fire-fighting standards with Chapter IV (GMDSS modernization) and Chapter II-2 (the prohibition of PFOS-containing foams)⁴⁴.

Chapter XI-1: Enhanced Maritime Safety and Hull Surveys

Chapter XI-1 regulates recognized organizations, enhanced structural surveys, and portable atmosphere testing³⁸.

The Enhanced Survey Programme (2011 ESP Code)

The ESP Code establishes additional survey requirements for bulk carriers and oil tankers, which are highly susceptible to localized corrosion, fatigue cracking, and structural failure⁶⁶.

•2024 Ballast Tank Coating Condition Amendments (MSC.525(106)): Revisions to the ESP Code that entered into force on 1 July 2024 align the ballast tank coating assessment criteria for bulk carriers with those applied to oil tankers⁹.

•Annual Survey Triggers: If the protective coating in a bulk carrier's water ballast tank is rated less than "GOOD" (meaning it is assessed as "FAIR" or "POOR"), the tank must undergo mandatory internal examinations at annual intervals⁶⁹. This annual examination schedule remains in place until the protective coating is restored to a "GOOD" condition⁷⁰.

•Double-Skin Void Spaces: For bulk carriers exceeding 20 years of age and in length, double-skin void spaces bounding the cargo holds must undergo internal examinations at annual intervals if their protective coatings are found to be in "POOR" condition⁶⁹.

•Cargo-tank testing under the 2011 ESP Code is survey-scope dependent. Pressure testing of cargo tanks is carried out where required by the applicable renewal/intermediate survey tables, ship age, tank condition and Administration/RO programme. It is not correct to state that every cargo tank must undergo hydrostatic pressure testing before any overall or close-up survey.

Enclosed Space Entrance Atmosphere Monitors (Regulation 7)

SOLAS XI-1/7 requires ships to carry an appropriate portable atmosphere testing instrument or instruments for enclosed-space entry. The instrument(s) must be capable, as a minimum, of measuring oxygen, flammable gases or vapours, hydrogen sulphide and carbon monoxide prior to entry. Applicability should be checked against the SOLAS regulation rather than presented merely as a generic '500 GT international voyage' rule.

•Four-Gas Detection Requirements: The vessel must carry at least one portable instrument capable of measuring the concentrations of the following four gases before any crew member enters a confined space⁶⁷:

1.Oxygen () concentration, measured by volume⁶⁷.

2.Flammable gases or vapors, measured as a percentage of the Lower Flammable Limit (LFL)⁶⁷.

3.Carbon Monoxide () concentration, measured in parts per million (ppm)⁶⁷.

4.Hydrogen Sulfide () concentration, measured in parts per million (ppm)⁶⁷.

•The required atmosphere-testing equipment must be suitable for pre-entry testing and capable of measuring the four specified hazards. Personal portable detectors used during entry may supplement the pre-entry test but do not remove the requirement to have suitable pre-entry testing equipment. A sampling pump may be necessary for remote sampling depending on the instrument and entry procedure, but SOLAS should not be quoted as universally requiring a separate dedicated pump-fitted instrument. Enclosed-space entry and rescue drills are required at intervals not exceeding two months under SOLAS III/19.

Chapter XI-2: Special Measures to Enhance Maritime Security

Chapter XI-2 mandates compliance with the International Ship and Port Facility Security (ISPS) Code, which regulates security systems for ships and port facilities².

SOLAS Chapter XI-2 and the ISPS Code apply to specified ships engaged on international voyages - including passenger ships, cargo ships of 500 GT and upwards, and mobile offshore drilling units - together with the relevant port facilities. Applicable ships must carry an approved Ship Security Plan, designate a Ship Security Officer, maintain the required security measures and comply with the three ISPS security levels.

•Security Level 1: The standard operating level, where minimum protective security measures are maintained at all times⁸.

•Security Level 2: The level of risk, where appropriate additional security measures are implemented due to a heightened risk of a security incident⁸.

•Security Level 3: The highest security level, where specific protective measures are maintained for a limited time when a security incident is probable or imminent, requiring coordination with port state authorities⁸.

Applicable ships must be fitted with a Ship Security Alert System (SSAS) in accordance with SOLAS XI-2/6. The system is activated from at least two locations, one of which is on the navigation bridge. The second activation point is arranged so that it is readily accessible and discreet; it should not be memorized universally as the captain's office. Activation sends a covert ship-to-shore security alert and should not raise an alarm on board.

This alert must not trigger any alarms on board the vessel, preventing attackers from realizing that a distress signal has been sent⁸.

Chapter XII: Additional Safety Measures for Bulk Carriers

Chapter XII regulates the structural strength, damage stability, and monitoring equipment of bulk carriers³⁸.

Water Level Detectors (Regulation 12)

Bulk carriers must be equipped with water level detectors in all cargo holds, ballast tanks, and dry spaces forward of the cargo area³⁸.

•Hold Detection Parameters: Level sensors in cargo holds must trigger audible and visual alarms at two distinct levels⁷²:

•Pre-Alarm: Triggered when water rises above the inner bottom⁷¹.

•Main Alarm: Triggered when the water level reaches of the depth of the cargo hold, up to a maximum height of ⁷².

•Dry Space and Ballast Tank Levels: Alarms in forward dry spaces (such as the chain locker and boatswain's store) must activate when water levels reach above the deck⁷¹.

•System Integrity: SOLAS XII/12 requires approved water-ingress detection and alarm arrangements for bulk carriers. Detailed construction, environmental protection, intrinsic-safety and installation requirements are governed by the applicable IMO performance standards and approved equipment specification. Do not present individual material grades, IP ratings or still-pipe arrangements as if they are all direct text of SOLAS XII/12.

•Intrinsically Safe Design: Because cargo hold atmospheres can contain explosive coal dust, the level detection circuits must be intrinsically safe (Ex ia)⁷¹. The bridge panel must feature a manual override switch to silence alarms when the hold is used for water ballast, with an automatic reset that reactivates the alarm when water levels drop below during deballasting⁷¹.

Chapter XIII: Verification of Compliance

Chapter XIII makes the IMO Member State Audit Scheme mandatory, establishing an auditing program to ensure that Contracting Governments fulfill their obligations as flag, port, and coastal States².

The chapter requires the IMO to audit each Member State at regular intervals to verify that it enforces the convention's technical and administrative requirements³⁸. These audits assess how effectively each administration registers vessels, delegates authority to Recognized Organizations, conducts statutory surveys, and executes Port State Control inspections².

By auditing Member States directly, Chapter XIII aims to maintain consistent global safety standards and prevent the proliferation of substandard shipping registers³⁸.

Chapter XIV: Safety Measures for Operating in Polar Waters

Chapter XIV makes the introduction and Part I-A of the International Code for Ships Operating in Polar Waters (the Polar Code) mandatory².

SOLAS Chapter XIV makes the safety-related provisions of the Polar Code mandatory. From 1 January 2026, the application of SOLAS Chapter XIV was expanded beyond ships already certified under SOLAS Chapter I to include fishing vessels of 24 m length overall and above, pleasure yachts of 300 GT and upwards not engaged in trade, and cargo ships of 300 GT and upwards but below 500 GT, for specified Polar Code safety-of-navigation and voyage-planning requirements. Ships certified under SOLAS Chapter I continue to comply with the full applicable safety requirements of Part I-A of the Polar Code.

Vessels must hold a Polar Ship Certificate, which requires them to carry specialized survival gear (such as insulated immersion suits), ice-detection radar, and winterized engine cooling systems designed to prevent ice blockage in seawater suctions³⁸.

Chapter XV: Safety Measures for Vessels Carrying Industrial Personnel

Chapter XV makes the International Code of Safety for Ships Carrying Industrial Personnel (IP Code) mandatory, filling a regulatory gap between standard cargo vessels and passenger ships⁹.

Scope of the IP Code

With the growth of the offshore wind energy and oil and gas sectors, there has been an increased demand for vessels that can carry large numbers of offshore specialists to energy facilities⁷⁷. Under older conventions, carrying more than 12 non-crew members classified a vessel as a passenger ship, requiring strict structural and stability compliance⁷⁸.

The IP Code entered into force on 1 July 2024 to regulate the safe transit and offshore transfer of these specialists³⁸. It applies to cargo ships and high-speed cargo craft of 500 GT and upwards engaged on international voyages that carry more than 12 industrial personnel, special personnel, and passengers combined, where the number of passengers must not exceed 12⁷⁷.

•Industrial Personnel: Persons transported or accommodated on board for the purpose of offshore industrial activities (such as construction, maintenance, decommissioning, or servicing of wind farms or oil installations)⁷⁷.

•Offshore Industrial Activities: Operations related to resource exploration, exploitation, or servicing by the renewable, hydrocarbon, aquaculture, or ocean mining sectors⁷⁷.

Engineering and Operational Requirements

The IP Code is based largely on the 2008 Special Purpose Ships (SPS) Code, with adaptations targeting the risks of offshore transit and transfer⁷⁸.

•Medical and Training Standards: Industrial personnel must meet strict standards for medical fitness, language communication, basic safety training (such as STCW or OPITO BST), and transfer-equipment familiarization⁷⁸.

•Personnel Transfer Systems: Transfer systems (including motion-compensated gangways, boat landings, and crane-hoisted capsules) must be designed, tested, and maintained to fail to a safe condition if power or hydraulic control is lost⁷⁹.

•Dangerous Goods Restrictions: If a vessel carries both bulk dangerous chemicals or liquefied gases and more than 12 industrial personnel, it must meet the safety standards of the IBC/IGC Codes or the OSV Chemical Code⁷⁸. Ships carrying toxic products, low-flashpoint cargoes, or acids are restricted to a maximum of 60 persons on board⁷⁸.

•Grandfathering Provisions: Existing vessels authorized to carry more than 12 industrial personnel under the interim recommendations of Resolution MSC.418(97) prior to 1 July 2024 may continue to operate, subject to completing an IP Code evaluation and certification audit by their first intermediate or renewal survey after that date⁸⁰.