SOLAS Chapter VI: Carriage of Cargoes and Oil Fuels

Background

Scope and structure of Chapter VI

Chapter VI governs the carriage of cargoes by ship, with three principal cargo regimes mapped to its four Parts:

• Part A general provisions applicable to all cargoes (cargo information, oxygen and gas detection, fumigation, stowage and securing).
• Part B specific to solid bulk cargoes other than grain, the regulatory shell that enables the IMSBC Code.
• Part C specific to grain, the regulatory shell that enables the International Grain Code.
• Part D the carriage of solid bulk cargoes covered by the IMSBC Code (a separate Part covering specific operational requirements not in Part B).

Chapter VI does not itself contain the engineering detail of cargo carriage. The detail is in three subsidiary mandatory instruments imported by reference:

• CSS Code (Code of Safe Practice for Cargo Stowage and Securing, originally voluntary but mandatory through Resolution MSC.81(70) for ships covered by Chapter II-2 Regulation 19).
• IMSBC Code (International Maritime Solid Bulk Cargoes Code, Resolution MSC.268(85), mandatory since 1 January 2011).
• International Grain Code (Resolution MSC.23(59), mandatory since 1 January 1994).

In addition, the BLU Code (Code of Practice for the Safe Loading and Unloading of Bulk Carriers, Resolution A.862(20)) provides operational guidance on bulk loading and unloading; while not mandatory, it is widely applied in industry practice and is referenced by some flag states as required.

Relationship to other chapters and to MARPOL

Chapter VI is closely linked to:

• Chapter II-1 for the stability of the ship under loaded conditions, including reserve stability after a damage scenario specified in Part B. The grain heeling moment in Part C contributes to the after-damage stability analysis.
• Chapter II-2 for the fire protection of cargo spaces, especially for IMDG cargoes under Chapter II-2 Regulation 19 and for the bilge and ventilation of holds carrying Class 1 to Class 5 IMDG cargoes.
• Chapter VII for the carriage of dangerous goods (the IMDG Code for packaged DG and the IMSBC Code for solid bulk DG). Chapter VII makes the IMDG Code mandatory through SOLAS reference; Chapter VI Part B does the same for the IMSBC Code.
• MARPOL Annex II for noxious liquid bulk cargoes (the IBC Code), Annex III for harmful substances in packaged form (interlocked with IMDG marine pollutant designations), Annex V for garbage from cargo residues, and Annex VI for emissions from bunker fuel use.

Major amendment history

• 1974: Chapter VI in the original SOLAS 1974 text covered grain only and the legacy “BC Code” (Code of Safe Practice for Solid Bulk Cargoes) was voluntary.
• 1991 (entered into force 1994): International Grain Code adopted as Resolution MSC.23(59) and made mandatory through SOLAS reference. The pre-existing 1969 Grain Rules became obsolete.
• 2008-2011: IMSBC Code adopted as Resolution MSC.268(85) and made mandatory through SOLAS reference, replacing the voluntary BC Code. The mandatory transition was a direct response to the recurrent liquefaction casualties of dry bulk carriers carrying mineral concentrates and ores at moisture content above the TML.
• 2010: CSS Code made mandatory through Resolution MSC.81(70) for ships subject to Chapter II-2 Regulation 19 carrying dangerous goods. The CSS Code annex containing detailed lashing standards for non-standardised cargoes also became mandatory.
• 2015: Amendments tightening shipper declarations under Regulation 2, requiring more rigorous certification of moisture content for Group A cargoes and supporting documentary evidence for the testing methods. The amendments followed the loss of the MV Bulk Jupiter (2015) carrying bauxite, where bauxite was shown to liquefy under conditions previously not recognised by the IMSBC Code.
• 2024: Amendments under development to address battery-grade nickel ore (a sub-class of Group A with more aggressive liquefaction behaviour), lithium-bearing cargoes (potential thermal runaway), and biofuel feedstocks (some with fire-related Group B sub-classification).

The amendment cycle reflects the regulatory tradition: a casualty (or cluster of casualties) drives a mandatory upgrade of a code that was previously voluntary, with subsequent fine-tuning as further casualties reveal new failure modes.

Part A: General

Application (Regulation 1)

Chapter VI applies to all ships engaged on international voyages carrying cargo (general, bulk, dangerous, or grain), with specific Regulations applying additionally to specific cargo types. Bulk carriers subject to Chapter XII (Additional Safety Measures for Bulk Carriers) carry forward the Chapter VI requirements with additional provisions specific to bulk carriers.

The application interacts with ship type. For example:

• A container ship is subject to Part A (general cargo information, stowage and securing) but not Part B (bulk cargoes) unless it is reconfigured for bulk operations.
• A bulk carrier is subject to Part A and Part B if carrying cargo other than grain, Part A and Part C if carrying grain, Part A and Part D if carrying IMSBC-coded cargoes.
• A general cargo ship is subject to Part A for any cargo, and to the relevant other Parts for any specific cargo type loaded.

Cargo information (Regulation 2)

Regulation 2 places the burden on the shipper, before the cargo is loaded, to provide the master and the master’s representative with cargo information sufficient to enable safe carriage. The information required includes:

• Cargo description (commercial name, technical name, UN number where applicable, product specification).
• Cargo characteristics (mass, stowage factor, angle of repose for bulk cargoes, moisture content for cargoes that may liquefy).
• Properties relevant to safe carriage (chemical hazards, explosive limits, flammable limits, reactivity with water or air, self-heating tendency, oxygen consumption).
• For solid bulk cargoes: the IMSBC Code group designation (A, B or C), the transportable moisture limit (TML) for Group A cargoes with a sworn declaration that moisture content is below TML at the time of loading, the chemical schedule reference for Group B.
• For dangerous goods: the relevant IMDG Code or IMSBC Code schedule reference.
• For deck cargoes: the lashing and securing instructions.

The information must be in writing and signed by the shipper. The master must satisfy himself that the information is consistent and that the cargo is safe to carry on the ship, and may refuse cargo where the information is incomplete, inconsistent, or where the master has reason to believe that the cargo is mis-declared.

Master’s verification of shipper’s declaration

The master is not required to passively accept the shipper’s declaration. The master may, and should, verify:

• Sample-based moisture content for Group A cargoes by drawing cargo samples and submitting them to a TML test (Flow Table Test, Penetration Test or Proctor-Fagerberg Test under IMSBC Code Section 8). If the test indicates moisture above TML, the master must refuse loading or require dewatering.
• Visual inspection of cargo characteristics (granular shape, colour, presence of liquid, condition of stockpile).
• Cross-checking with the shipper’s certificate of analysis.
• Consistency check against the IMSBC Code schedule for the declared cargo type.

The master’s authority is supported by Chapter VI and by the SMS under the ISM Code. Master refusal is a recognised regulatory action and is supported by the IMO MSC/Circ.1380 series of clarifications.

The Reg VI/2 cargo information calculator walks through the required fields for a given cargo type.

Oxygen analysis and gas detection equipment (Regulation 3)

Ships carrying cargoes that may emit flammable, toxic or oxygen-depleting gases must carry portable oxygen analysers and gas detection equipment, with crew trained to use them. The requirement applies to:

• Solid bulk cargoes that consume oxygen or generate toxic gas: coal (CO and oxygen depletion), sulphide ores (SO2 and H2S), fishmeal (CO2 and oxygen depletion through bacterial action), vegetable seed cake (oxygen depletion), charcoal, direct reduced iron (hydrogen).
• Mineral concentrates that may release sulphur dioxide or hydrogen sulphide on contact with water.
• Cargoes prone to self-heating with associated CO release: coal, fishmeal, certain mineral concentrates.

Specific equipment requirements:

• Portable oxygen analyser with measurement range 0 to 25 percent oxygen with accuracy of at least 0.5 percent of full scale.
• Portable combustible gas detector covering the lower explosive limit (LEL) range with calibration for methane, propane or other relevant gas.
• Specific toxic gas sensors (CO, H2S) for cargoes that may release these.
• Battery operation with sufficient duration for hold entry surveys and emergency response.
• Calibration records demonstrating periodic calibration with reference gases.
• Crew trained to operate the equipment and to interpret the readings.

The IMO MSC.1/Circ.1264 (Recommendations on the carriage of bulk cargoes liable to liquefy or to develop oxygen-deficient atmospheres) provides operational detail.

Use of pesticides (Regulation 4)

Pesticides may be used on board for fumigation of cargo (in-transit fumigation of grain and other agricultural cargoes), for fumigation of empty holds before loading, and for treatment of crew accommodation against insects. Regulation 4 requires:

• Use of approved fumigants only (typically aluminium phosphide or methyl bromide for grain; sulfuryl fluoride for dry-stores; phosphine for various agricultural products).
• Pre-fumigation notification to the master with safety procedures.
• In-transit fumigation only with the master’s agreement and only where ventilation arrangements permit residual gas dissipation before crew entry.
• Post-fumigation gas check before crew entry into the fumigated space.
• Fumigation operator training and certification (a fumigator’s permit issued by the supplier or by a recognised training body).
• Documentation of the fumigation: gas type, application rate, application time, expected dissipation time, ventilation requirements.
• Crew familiarisation with the fumigation procedure including evacuation routes, emergency response, first aid for fumigant exposure.

Aluminium phosphide fumigation

Aluminium phosphide tablets, when exposed to atmospheric moisture, generate phosphine gas (PH3), a fast-acting fumigant for grain and other dry agricultural cargoes. The fumigant is effective against insects but lethal to humans at concentrations above approximately 7 ppm with prolonged exposure. Specific operational requirements include:

• Master’s authority to refuse fumigation if the ventilation arrangements are inadequate.
• Posting of warning signs at all entries to the fumigated space.
• Sealing of the space at the start of fumigation and verification of seal integrity.
• Periodic gas measurement during the dissipation period.
• Ventilation requirements before entry, with verified gas concentration below 0.3 ppm before entry.
• First-aid arrangements (oxygen, evacuation route to fresh air).

Methyl bromide fumigation

Methyl bromide is a more aggressive fumigant used for high-value cargoes (specialty grains, ginseng) and for empty hold fumigation. The gas is heavier than air and persistent in stowed cargoes. Use of methyl bromide is increasingly restricted under the Montreal Protocol due to its ozone-depleting effect, though specific maritime applications retain critical-use exemptions.

Stowage and securing (Regulation 5)

Cargo carried on board must be stowed and secured to prevent damage to the ship and to the cargo, and to prevent risks to persons. The implementation is through:

• The Cargo Stowage and Securing (CSS) Code, mandatory under Resolution MSC.81(70).
• The ship-specific Cargo Securing Manual (CSM), prepared at delivery and approved by the flag state, kept on board, and updated when the cargo securing arrangements change.
• The shipper’s lashing instructions for non-standard cargoes.

The CSM contains:

• Description of cargo securing equipment provided on the ship.
• Specifications of fixed cargo securing equipment (pad eyes, lashing pots, twist-locks for containers, deck rings).
• Specifications of portable cargo securing equipment (chains, lashing ropes, tensioning devices) including breaking strength.
• Stowage and securing instructions for typical cargo types.
• Procedures for inspection and maintenance of securing equipment.
• Cargo information forms to be completed for each consignment.

The Reg VI/5 stowage and securing calculator and the Cargo Securing Manual article provide further detail.

Container lashing

Container ships use a mature lashing system involving:

• Twist locks between containers (vertically and corner-to-corner) preventing horizontal slip and lift.
• Lashing rods connecting from container corner castings down to the deck or to lashing bridges.
• Turnbuckles for tensioning the lashing rods after stowage.
• Stacking weights balanced so heavier containers are at the bottom and lighter at the top.
• Wind area limits for the deck stack height to keep wind heeling within design limits.

Each ship’s CSM specifies the maximum stack heights for various container weight distributions and weather conditions. The ship’s loading computer generates the lashing arrangement and verifies that the resulting forces (transverse, longitudinal, vertical, racking) are within the certified strength of the lashing equipment.

Ro-ro lashing

Ro-ro vessels (vehicle carriers, ro-pax) use a different lashing approach:

• Web lashings from cargo (cars, trailers, machinery) to deck pad eyes.
• Cradles or chocks for unwheeled cargo.
• Trestles for trailers without wheels.
• Hold-fast clips for containers on chassis.
• Deck-rated tie-down points at standardised intervals.

The CSM specifies the lashing pattern by cargo type and weather conditions; trailers in particular require closer lashing in heavy weather.

Heavy-weather operational adjustments

The CSS Code recognises that the design lashing arrangement may not be adequate for severe weather. Operational practice includes:

• Reducing speed to limit ship motions.
• Heaving-to or making for shelter if weather forecast deteriorates.
• Re-securing of cargo at sea if accessible (limited to specific cargo types in conditions that permit).
• Pre-voyage weather routing (under Chapter V Regulation 34) to avoid worst weather.

The 2020 to 2022 cluster of container losses (MOL Comfort 2013, ONE Apus 2020, Maersk Eindhoven 2021, Tokyo Express 2022) drove industry-led initiatives to revise lashing patterns and to integrate weather routing more closely with stowage planning.

Part B: Special provisions for solid bulk cargoes other than grain

Acceptability for shipment (Regulation 6)

Before solid bulk cargo is accepted for loading, the master must verify:

• That the cargo information has been provided in compliance with Regulation 2.
• That the cargo, in the form and quantity offered, is suitable for carriage on the ship.
• That the ship is suitable for the cargo (some bulk cargoes require specific hold preparation, ventilation, fixed CO2 capability, or hold geometry).
• That no part of the cargo presents an unacceptable hazard (typically through random sampling of moisture content for Group A cargoes by the master or master’s representative).

For Group A cargoes (those that may liquefy), the IMSBC Code requires a Master’s Confirmation of moisture content based on the shipper’s declaration plus the master’s assessment.

Group A cargoes and liquefaction

Liquefaction is the process by which fine-particle cargoes (typical particle size below 1 mm) at sufficient moisture content can transition from a solid-like packed state to a viscous fluid under cyclic vibration (the rolling and pitching of a ship at sea). The transition occurs because:

• The pore water in the cargo is compressed by the cyclic loading.
• Pore water pressure rises until it equals the inter-grain stress.
• At equilibrium, the grains lose contact with each other and the cargo behaves as a fluid.
• The fluidised cargo flows under gravity, creating a shifting cargo geometry.

The shifted cargo creates a heeling moment proportional to the displacement of the cargo from its design centre of gravity. If sufficient cargo shifts, the heeling moment exceeds the ship’s righting moment and the ship capsizes.

The IMSBC Code addresses liquefaction by:

• Group A classification of cargoes known to be susceptible.
• TML determination for each Group A cargo, using one of three test methods (Flow Table Test, Penetration Test, Proctor-Fagerberg Test).
• Moisture content monitoring before and during loading.
• Refusal of cargo if moisture content is above TML.

The IMSBC Group A cargoes article covers the test methods in greater depth.

Loading, unloading and stowage (Regulation 7)

Loading and unloading of solid bulk cargo must be carried out in accordance with:

• The cargo distribution plan agreed between the master and the terminal, ensuring that the loading rate, sequence and final distribution do not exceed the structural strength of the ship at any stage.
• The BLU Code (Code of Practice for the Safe Loading and Unloading of Bulk Carriers, voluntary but widely applied) and the BLU Manual which provides operational detail.
• The ship-specific loading manual and the loading computer (mandatory on bulk carriers per Chapter II-1 and Chapter XII).
• The required pre-loading stability documentation including damage stability if applicable.

BLU Code provisions

The BLU Code organises bulk loading and unloading into a four-party framework:

• Master: ultimate responsibility for ship safety and refuses cargo or operations that compromise safety.
• Terminal representative: responsible for terminal-side operations (loading rate, conveyor positioning, queue management).
• Ship’s loading officer: typically the chief officer, responsible for in-ship operations during loading.
• Surveyor (where applicable): independent verification of cargo quantity and condition.

The four parties exchange a Ship-Shore Safety Checklist before commencement of loading or unloading, covering:

• Communication arrangements (radio channels, contact persons).
• Cargo distribution plan (sequence, rate, final distribution).
• Ship hull stress and stability margins.
• Emergency response (fire, spillage, equipment failure).
• Hold preparation and access.
• Weather conditions.

Loading rate-arm calculations

The loading rate-arm calculation determines the maximum loading rate for each hold based on the structural strength of the hull girder at intermediate loading conditions. The bulk loading rate-arm calculator implements the calculation, taking ship type, hull girder section modulus, and the loading sequence as inputs.

The calculation is necessary because rapid loading of a small number of holds can create high local hull-girder stresses while the rest of the ship is still light. The ship’s structure is designed for the final fully-loaded condition; intermediate states with uneven loading can exceed the structural design.

Unloading sequence and pre-departure stress checks

Unloading is the inverse: the cargo distribution must be progressively de-loaded in a sequence that does not exceed structural limits. The post-unloading bay-by-bay structural verification is one of the most-cited reasons for delayed sailings on bulk carriers.

Part C: Carriage of grain

The International Grain Code

Grain (cereals: wheat, maize, rice, barley, oats, rye and processed forms; pulses: peas, beans, lentils; seeds with similar properties: rapeseed, sunflower seed, soybean) presents a specific carriage hazard. Grain in a partially-filled compartment shifts during the voyage as the ship rolls. The shifted grain creates a heeling moment that can degrade ship stability or cause capsize.

The International Grain Code (Resolution MSC.23(59)) sets out the calculation methodology and the carriage criteria:

Volumetric assumption

In a partially-filled compartment, the grain settles by 2 percent of compartment height during normal voyage, leaving a void at the top. The shift assumption is:

• Compartment fully loaded with overstow: no shift assumed (the cargo cannot move because it fills the compartment).
• Compartment partially loaded: shift assumed during a 25-degree heel, with the grain surface tilting to a new angle equal to the angle of repose (typically 25 to 35 degrees) measured from horizontal.

The 25-degree heel assumption is conservative; many operational rolls are at smaller angles. The 2 percent settlement is an empirical figure based on experience with grain consolidation in stowage.

Heeling moment computation

The heeling moment is calculated by integrating the volumetric shift over the compartment geometry:

For a rectangular compartment of dimensions L (length), B (breadth), H (height):

• The void at the top has a depth of 0.02 × H (the 2 percent settlement assumption).
• After 25-degree heel and shift-to-angle-of-repose, the grain occupies a new shape with:
  • One side higher than the other by approximately B × tan(angle of repose) / (1 + 0.02 H/B) (geometrically).
  • The shifted volume is approximately (B^2 × tan(angle of repose) × L) / 8.
• The shift creates a transverse moment of approximately (volume × density × shift distance from centreline) / displacement.

The detailed calculation accounts for the actual compartment geometry, which is rarely rectangular: bulk carrier holds have hopper sides and sloped bottoms that change the shift calculation.

Stability criteria after grain shift

The ship must satisfy these criteria after the assumed grain shift:

• The angle of heel due to the assumed grain shift must not exceed 12 degrees for ships of 100 m or more (less for smaller ships).
• The residual GZ (righting arm at the angle of grain-shift heel) must give a positive area between the GZ curve and the heeling moment curve up to the angle of progressive flooding.
• The maximum residual GZ must not be less than 75 percent of the maximum GZ in intact condition.

These criteria ensure that the ship retains substantial stability margin even after the worst-case grain shift.

Authorised methods of compliance

Compliance with the heel and stability criteria is achieved through one of:

• Filled compartments: compartment loaded with grain to the maximum extent practicable; the residual void is small and the grain shift assumption gives a small moment.
• Partial loading with strapping or lashing: surface of the grain is overstowed with bagged grain or covered with a temporary structure that mechanically prevents shifting. The strapping uses synthetic mesh, tarpaulin, or specialised flexible bags placed on the grain surface and tensioned to restrict surface movement.
• Saucers or shifting boards: portable bulkheads (longitudinal or transverse) that limit the compartment volume into which grain can shift. Saucers are typically wooden boards in a pyramid arrangement; shifting boards are larger longitudinal partitions running fore and aft.
• Compliance by calculation only with documented additional GM: ships with reserve GM may carry grain in partial loading without physical securing.

Document of Authorization to carry grain

A ship loading grain in bulk must hold a Document of Authorization issued by the flag state (or by a recognised organisation acting for the flag state), valid for a defined period and listing the conditions under which the ship is authorised to carry grain (loading conditions, holds usable, any restrictions). The document is checked at loading and is required at port state control inspection of grain-loaded ships.

Grain heeling moment calculator

The grain heel calculator and the bulk cargo displacement grain calculator compute the grain heeling moment and resulting heel angle for a given ship and grain stowage. Cargo-specific schedules for corn, wheat, rice bran and soybeans provide IMSBC-aligned data for the principal grain cargoes.

Part D: Carriage of solid bulk cargoes covered by IMSBC

The IMSBC Code, mandatory under Resolution MSC.268(85), governs the carriage of solid bulk cargoes other than grain. It is structured into 13 Sections covering:

• Section 1: General provisions.
• Section 2: General loading, carriage and unloading precautions.
• Section 3: Safety of personnel and ship.
• Section 4: Assessment of acceptability of consignments for safe shipment.
• Section 5: Trimming procedures.
• Section 6: Methods of determining angle of repose.
• Section 7: Cargoes that may liquefy (Group A).
• Section 8: Test procedures for cargoes that may liquefy (Flow Table Test, Penetration Test, Proctor-Fagerberg Test).
• Section 9: Materials possessing chemical hazards (Group B).
• Section 10: Carriage of dangerous goods.
• Section 11: Security provisions.
• Section 12: Stowage factor conversion tables.
• Section 13: References to related information.

Plus an Appendix 1 containing the Individual Schedules of Solid Bulk Cargoes: alphabetically organised entries for each cargo (aluminium ore, bauxite, coal, copper concentrate, iron ore fines, nickel ore, etc.) with stowage factor, angle of repose, group classification, hazards, weather precautions, ventilation requirements, segregation requirements, and emergency procedures.

The IMSBC Code article and the IMSBC Group A cargoes article cover the Code in greater depth.

IMSBC Group A: Cargoes that may liquefy

Group A cargoes are those liable to liquefy. The IMSBC Code requires for each such cargo:

• TML determination by one of three approved test methods.
• Master’s verification of moisture content at loading.
• Trimming of the cargo to keep the surface as level as possible (an uneven surface concentrates moisture in low spots).
• Operational restrictions on weather routing (avoiding heavy weather where practicable).
• Continuous monitoring during voyage of the cargo surface (where accessible) and any visible signs of liquefaction.

Test methods for TML

• Flow Table Test (FTT): a sample of cargo is placed on a flow table, the table is dropped 25 times in 15 seconds, and the resulting flow is measured. The TML is the moisture content at which flow exceeds defined limits.
• Penetration Test: a cone is dropped onto the cargo surface and the depth of penetration is measured at increasing moisture contents. The TML is the moisture at which penetration first exceeds the threshold.
• Proctor-Fagerberg Test: the cargo is compacted at various moisture contents and the resulting bulk density is plotted. The TML is determined from the optimum moisture content of the compaction curve.

The three tests give similar results for most cargoes but differ for specific cargo types; the IMSBC Code Section 8 allows the use of any of the three but recommends specific tests for specific cargo types.

IMSBC Group B: Cargoes with chemical hazards

Group B cargoes have chemical hazards beyond simple combustibility:

• Coal: emits CO and depletes oxygen in adjacent spaces; some coals are self-heating.
• Direct reduced iron (DRI): emits hydrogen and self-heats violently in contact with water.
• Sulphide ores: emit sulphur dioxide on contact with moisture or air.
• Fishmeal: self-heats and emits CO; spontaneous combustion risk if moisture content is excessive.
• Vegetable seed cake: self-heats and depletes oxygen.

For each Group B cargo, the IMSBC Code provides:

• Hazard description.
• Stowage requirements (hold preparation, ventilation arrangements).
• Segregation requirements (separated from oxidisers, acids, cyanides as appropriate).
• Operational precautions (gas monitoring, hot work restrictions).
• Emergency response (fire, spillage, exposure).

IMSBC Group C: Cargoes with no special hazards

Group C cargoes have neither liquefaction nor chemical hazards, but are still subject to the general IMSBC Code requirements (cargo information, loading procedures, stability documentation). Examples include cement, gypsum, salt, sand, scrap metal.

Notable casualties

MV Derbyshire, 1980

The British-flagged bulk carrier MV Derbyshire foundered in Typhoon Orchid south of Japan on 9 September 1980 with 44 dead. The investigation, completed many years later, identified failure of the No. 1 hatch cover as a contributing factor. The casualty was a foundational driver of Chapter XII (Additional Safety Measures for Bulk Carriers) and contributed to tightening of shipper declarations under Regulation 2.

The 26-year investigation completed in 2000 was one of the most extensive in maritime history, involving:

• Underwater survey of the wreck at 4,200 metres depth.
• Recovery of structural samples for metallurgical analysis.
• Reconstruction of the casualty sequence from wreckage distribution.
• Analysis of weather and sea-state at the time of loss.

The conclusions drove:

• Strengthened hatch cover design (for ships above 100,000 tonnes deadweight).
• Strengthened forward fore-end deck plate scantlings to withstand green seas.
• Forward bulkhead verification of damage stability.
• Independent forecastle as required reserve buoyancy.

MV Vinalines Queen, 2011

The Vietnam-flagged bulk carrier MV Vinalines Queen capsized in the Pacific on 25 December 2011 carrying nickel ore from Indonesia, with 22 of 23 crew lost. Liquefaction of the Group A nickel ore cargo was identified as the cause. The casualty was a direct driver of post-IMSBC Code amendments tightening Group A moisture content verification.

MV Bulk Jupiter, 2015

The bulk carrier MV Bulk Jupiter sank in the South China Sea on 2 January 2015 carrying bauxite from Malaysia, with 18 of 19 crew lost. Liquefaction of the bauxite cargo (an unusual finding because bauxite was not classed as Group A at the time) led to the addition of bauxite fines to Group A in subsequent IMSBC amendments.

The bauxite case illustrated the limitations of the static IMSBC Code: a cargo that had been considered safe became unsafe when shipped from a different source with different moisture characteristics. The amendment cycle now includes explicit pathways for adding new cargo entries to Group A based on field experience.

MV Stellar Daisy, 2017

The Marshall Islands-flagged Very Large Ore Carrier MV Stellar Daisy split and sank in the South Atlantic on 31 March 2017 carrying iron ore fines from Brazil to China, with 22 of 24 crew lost. The casualty triggered investigation of the structural integrity of converted VLOCs (the ship had been converted from a tanker) and contributed to IACS unified requirements on bulk carrier structure.

Container losses overboard

Multiple recurring incidents of large container losses overboard from container ships in heavy weather have drawn attention to lashing standards:

• MOL Comfort, 2013: split in two and sank in the Indian Ocean carrying about 4,500 TEU.
• ONE Apus, 2020: lost approximately 1,800 containers overboard in the Pacific in heavy weather.
• Maersk Eindhoven, 2021: lost approximately 260 containers overboard.
• Tokio Express, 2022: lost approximately 65 containers overboard.

These incidents drove industry-led tightening of container lashing patterns, stowage planning integration with weather routing, and reduction in stack heights for adverse weather forecasts. IMO MSC has amendments under development to the CSS Code addressing parametric rolling and container loss prevention.

Container fires from mis-declared dangerous goods

A separate cluster of container ship casualties (Maersk Honam 2018, X-Press Pearl 2021) involved fires originating in mis-declared dangerous goods. These casualties bridge the gap between Chapter VI (cargo information) and Chapter VII (dangerous goods) and Chapter II-2 (fire). The CINS (Cargo Incident Notification System) industry database now tracks mis-declared cargo incidents at scale.

Specific cargo operational considerations

Iron ore

Iron ore is the largest single bulk-cargo commodity by tonnage, with annual world trade exceeding 1.5 billion tonnes. The principal categories under IMSBC are:

• Iron ore (lump and sinter feed): typically Group C with no special hazards, stowed in accordance with general IMSBC procedures.
• Iron ore fines (IOF): Group A liable to liquefy if shipped above the TML. The schedule was added to the IMSBC Code in 2013 after the Vale Brazil cluster of investigations and the loss of the MV Vinalines Queen (2011).
• Iron ore concentrate: pelletised or fine-particle concentrate from beneficiation plants; typically Group A, with TML test required.

Iron ore is loaded at major terminals (Port Hedland, Dampier, Saldanha Bay, Tubarão, Ponta da Madeira) at very high rates (up to 12,000 tonnes per hour from a single shiploader). The high rate requires careful management of the ship’s loading sequence to avoid stress concentration.

The IMSBC iron ore fines calculator implements the moisture verification.

Coal

Coal is a major bulk cargo (annual world trade approximately 1.3 billion tonnes) with multiple hazards:

• Self-heating: coal in storage produces methane, carbon monoxide and hydrogen sulphide. Self-heating can lead to spontaneous combustion if oxygen access is inadequately restricted.
• Oxygen depletion: bacterial action and bacterial oxidation depletes oxygen in adjacent enclosed spaces. Crew entry to coal-stowed holds requires gas testing for both oxygen content and CO concentration.
• Methane release: coal beds release methane as the cargo is loaded, with potential for accumulation in enclosed spaces.
• Liquefaction risk: certain fine coal cargoes (slurries, beneficiation tailings, some run-of-mine cargoes with high moisture) are Group A liable to liquefy.

The IMSBC Code coal schedule requires enclosed-space gas monitoring, ventilation arrangements, and specific stowage and segregation. Hot work near coal cargo is forbidden during voyage.

Bauxite

Bauxite is mined in Indonesia, Australia, Guinea, Brazil and other producers as feedstock for alumina refining. Following the loss of the MV Bulk Jupiter (2015), bauxite fines were added to Group A in IMSBC 2017 amendments. The hazard arises from fine bauxite particles (under 1 mm) at high moisture content liquefying under voyage motion.

The IMSBC schedule for bauxite distinguishes between:

• Lump bauxite (run-of-mine, typically above 25 mm particle size): Group C, no liquefaction hazard.
• Bauxite fines: Group A, with TML test required. Specific reference to the Modified Proctor-Fagerberg Test is required for bauxite TML determination because the standard tests under-predict the liquefaction risk.

Direct reduced iron (DRI)

Direct Reduced Iron is metallic iron produced by reduction of iron ore at temperatures below the melting point. It is highly reactive in contact with water and air:

• Reaction with water releases hydrogen, with high heat output.
• Reaction with atmospheric oxygen produces self-heating, with risk of fire.
• Stowage requires inerting (typically with nitrogen) and continuous gas monitoring.

Three forms of DRI are classified separately under IMSBC:

• DRI(A): hot-briquetted iron, Group B, requires inerting.
• DRI(B): lumps/pellets/cold-moulded briquettes, Group B, requires inerting.
• DRI(C): by-product fines, Group B, requires inerting.

DRI carriage requires:

• Inert gas system maintaining cargo space oxygen below 5 percent.
• Continuous monitoring of oxygen, hydrogen, and hold temperature.
• Watertight hold to prevent water ingress.
• Specialised crew training in DRI hazard management.

The MV Adamandas (2009) and other DRI casualties have driven progressive tightening of IMSBC requirements for this cargo.

Ballast water management interaction

Bulk carriers operate with substantial ballast water exchange between voyages: a fully laden bulk carrier de-loads cargo at discharge and takes on equivalent ballast for the return voyage. The interaction with the Ballast Water Management Convention is significant:

• Ballast loading sequence: matched with cargo discharge to maintain hull strength and stability throughout the operation.
• Ballast water treatment: required under BWM Convention to prevent invasive species transfer; the treatment system (typically UV, electrolysis or active substance) operates during ballast intake.
• Ballast tank inspection: under the Enhanced Survey Programme of Chapter XII, ballast tanks receive close-up inspection due to the corrosive marine environment.

Bulk carrier ballast tank coatings (under IMO PSPC, Performance Standard for Protective Coatings) are required to have 15-year nominal life with periodic touch-up.

Bunker fuel as cargo

Although the chapter title refers to “cargoes and oil fuels”, the carriage of bunker fuel is governed in practice through:

• Chapter II-1 Part C and Part G for the engineering arrangements (fuel oil tanks, fuel transfer, fuel preparation rooms, double-walled fuel piping, leak detection, hazardous-area zoning around fuel pumps and supply manifolds, IGF Code for low-flashpoint fuels including LNG, methanol, ammonia and hydrogen).
• MARPOL Annex I for prevention of oil pollution from bunker tank leaks.
• MARPOL Annex VI for sulphur content limits, NOx limits, particulate matter limits, EEDI, EEXI and CII requirements.
• STCW Section A-V/3 for crew training in fuel system operation (especially LNG, methanol, ammonia under the IGF Code).

Chapter VI Part A applies to bunker operations in two specific senses:

• Cargo information equivalent: the fuel supplier provides a Bunker Delivery Note (BDN) and Bunker Fuel Sample under MARPOL Annex VI and ISO 8217 (Marine Fuel Quality Specification), serving the same regulatory purpose as a cargo information declaration.
• Stowage and securing is not relevant for liquid bunker but applies to bunker drums and bunker IBCs where they are carried as deck cargo.

The interaction with Chapter II-2 is significant: bunker fuel transfer is one of the highest-risk routine operations, with bunker spillage onto a hot machinery space surface being a recognised ignition source.

Port state control inspections of cargo carriage

Port state control (PSC) inspections of cargo carriage focus on:

• Cargo manifest verification against the Document of Compliance for the Carriage of Dangerous Goods (under Chapter VII) and against the IMSBC Code.
• Shipper declaration verification for randomly sampled containers or bulk consignments.
• Stowage and securing inspection of deck cargo, including verification that the actual stowage matches the lashing plan and CSM.
• Cargo Securing Manual examination, with specific attention to recent amendments and to the loading conditions documented for the voyage in progress.
• Loading instrument and loading manual review, with verification that the loading computer has been used and that the calculated stresses are within limits.
• Group A moisture certification for cargo declared as Group A, with random sampling for verification.
• Hatch cover and hold integrity inspection on bulk carriers, especially after voyage with green-water exposure.
• Fumigation certificate verification on cargoes that have been fumigated in transit, with confirmation that residual gas levels have been measured before crew entry.

Major PSC regimes (Paris MOU, Tokyo MOU, US Coast Guard, AMSA, China MSA) include cargo carriage in their inspection categories. Detentions for cargo-related deficiencies are common and are recorded against the operator’s PSC profile.

Heavy weather damage to deck cargo

Recent container loss casualties illustrate the operational reality that even well-secured cargo can be lost in extreme weather:

• MOL Comfort, 2013: split in two and sank in the Indian Ocean carrying about 4,500 TEU. Investigation pointed to a combination of structural fatigue and bow flexural overload in heavy seas.
• ONE Apus, 2020: lost approximately 1,800 containers overboard in the Pacific in heavy weather, with parametric rolling identified as a contributing factor.
• Maersk Eindhoven, 2021: lost 260 containers overboard.
• Tokio Express, 2022: lost 65 containers, with several containing dangerous goods.

The post-incident analyses converge on several observations:

• Parametric rolling (resonance between encounter wave frequency and ship’s natural roll frequency) can produce roll amplitudes well beyond design assumptions.
• Lashing system limits are exceeded when roll exceeds approximately 25 to 30 degrees, with progressive failure cascading through the stack.
• Stack height has grown faster than the lashing standards have updated; modern stacks of 8 to 10 containers high create high overturning moments.
• Weather routing has not always been integrated with stowage planning; ships have been routed through severe weather while loaded with stowage patterns marginal for that weather.

The IMO MSC has amendments under development to the CSS Code addressing parametric rolling avoidance and reduction of stack heights for adverse weather forecasts.

Documentation

Every ship covered by Chapter VI carries on board:

• The Cargo Ship Safety Construction Certificate (under Chapter I), with evidence of compliance with Chapter VI through the IMSBC Code, Grain Code and CSS Code as applicable.
• The ship-specific Cargo Securing Manual approved by the flag state.
• The Document of Authorization to carry grain (under the Grain Code).
• The cargo information declarations from the shipper for each consignment under Regulation 2.
• The hold preparation and inspection records.
• The fumigation certificates and post-fumigation gas check records under Regulation 4.
• The IMSBC Code copy on board (with all current amendments).
• The International Grain Code copy on board.
• The CSS Code copy on board.
• The BLU Manual (recommended).
• Pre-loading stability documentation including loading computer outputs.
• For container ships: the bay plan and lashing plan generated by the loading computer.
• For ro-ro vessels: the deck stowage plan with cargo securing details.

Related Calculators

• SOLAS VI/2, Cargo information (VGM) Calculator
• SOLAS VI/5, Stowage and securing Calculator
• SOLAS VII/3, Carriage of dangerous goods Calculator
• Grain, Cargo Displacement Volume Calculator
• Grain Heeling, Volumetric Heeling Moment Calculator
• Bulk, Shore Loading Rate Check Calculator
• IMSBC (Grain) Corn Calculator
• IMSBC (Grain) Wheat Calculator
• IMSBC (Grain) Rice Bran Calculator
• IMSBC (Grain) Soybeans Calculator
• IMSBC, Iron Ore Fines (IOF) Calculator

See also

• SOLAS Convention parent article
• SOLAS Chapter II-1: Construction, Subdivision, Stability, Machinery and Electrical Installations
• SOLAS Chapter II-2: Fire Protection, Detection and Extinction
• SOLAS Chapter III: Life-Saving Appliances and Arrangements
• SOLAS Chapter V: Safety of Navigation
• IMSBC Code
• IMSBC Group A cargoes
• Cargo Securing Manual
• Bulk Carrier
• Container Ship
• IMDG Class 1 Explosives (linked through Chapter VII)
• IMDG Class 4 Flammable Solids
• MARPOL Convention

Additional calculators:

• IMSBC Group A - Liquefaction Risk
• IMSBC TML Moisture Check
• IMSBC Group A/B/C Classification
• Iron Ore Fines - Moisture Check

Additional formula references:

• Imsbc Iron Ore Fines Iof
• Bulk Loading Rate Arm
• Bulk Iof Moisture
• Imsbc Angle Repose

Additional related wiki articles:

• SOLAS Chapter XII: Additional Safety Measures for Bulk Carriers

References

• IMO, International Convention for the Safety of Life at Sea (SOLAS), 1974, as amended, Chapter VI.
• IMO, International Maritime Solid Bulk Cargoes Code (IMSBC Code), Resolution MSC.268(85), 2008, as amended.
• IMO, International Code for the Safe Carriage of Grain in Bulk (International Grain Code), Resolution MSC.23(59), 1991, as amended.
• IMO, Code of Safe Practice for Cargo Stowage and Securing (CSS Code), Resolution A.714(17), as amended.
• IMO, Code of Practice for the Safe Loading and Unloading of Bulk Carriers (BLU Code), Resolution A.862(20).
• IMO MSC/Circ.1380 and successor circulars on liquefaction risk and Group A cargoes.
• IMO MSC.1/Circ.1264, Recommendations on the carriage of bulk cargoes liable to liquefy or develop oxygen-deficient atmospheres.
• INTERCARGO Bulk Carrier Casualty Reports, annual.
• World Shipping Council Container Lost At Sea reports, biennial.
• CINS Cargo Incident Notification System Annual Reports.