Question 1

You are presented with a cargo of iron ore fines. Recent rainfall has occurred at the loading port. Describe your obligations under the IMSBC Code before loading.

Accepted Answer

IMSBC GROUP A CARGO — IRON ORE FINES PRE-LOADING ASSESSMENT: IMSBC CODE GROUP A: cargoes that may liquefy when shipped above their Transportable Moisture Limit (TML). Iron ore fines are a GROUP A cargo under the IMSBC Code (Schedule). Liquefaction risk: when shipped above TML, vibration during the voyage causes solid cargo to behave as a liquid — flow shifts occur, vessel develops list, potentially capsizing rapidly. RECENT RAINFALL: this is the critical context. Post-rainfall — iron ore fines absorb surface water. The moisture content may have risen ABOVE the TML. PRE-LOADING MANDATORY REQUIREMENTS: (1) MOISTURE CONTENT CERTIFICATE: the shipper MUST provide a certificate showing the moisture content of the cargo and confirming it is below the TML. This must be issued within 7 days of loading; (2) TML CERTIFICATE: the shipper must provide the TML for the specific cargo (tested at an approved laboratory). The TML must be certified; (3) FLOW MOISTURE POINT TESTING: the TML is typically 90% of the Flow Moisture Point (FMP); (4) MASTER's ASSESSMENT: (a) Compare the certified moisture content with the TML; (b) If moisture content ≥ TML — REFUSE TO LOAD; (c) If recent rainfall and moisture certificate seems inconsistent (very dry result after heavy rain) — request re-testing or independent test; (5) CAN TEST (INFORMAL): shake a can-sized sample of the cargo to see if moisture separates. This is an indicator — it is NOT a substitute for formal laboratory testing; (6) INDEPENDENT LABORATORY: the master may request an independent moisture test from an approved laboratory if they question the shipper's certificate. Liquefaction casualties: iron ore fines liquefaction has caused multiple catastrophic casualties. The MV Stellar Daisy (2017) — a 266,000-tonne VLOC carrying Brazilian iron ore fines sank in the South Atlantic with 22 crew lost. The investigation identified liquefaction as a probable cause. The MV Asian Forest (2016) and others. These are real, documented casualties where hundreds of seafarers died. Cargo liquefaction can cause capsize in MINUTES with no time to abandon ship. Shipper certificate — not absolute (option B): the IMSBC Code (Para 4.3.4) requires the shipper to provide the certificate — but it also requires the MASTER to be satisfied that the cargo is safe to load. The IMSBC Code explicitly gives the master the right to request additional testing if the certificate is questioned. A master who loads a suspect cargo solely because a certificate exists, when circumstances (recent rainfall, visual inspection) suggest elevated moisture, may bear partial responsibility for any casualty. Post-rainfall validity (option C): iron ore fines are porous particulate materials — they absolutely DO absorb surface water from rainfall. A moisture certificate taken before recent heavy rain may not reflect the current moisture content. The 7-day validity limit on moisture certificates exists precisely because moisture content changes over time and with weather. Load and monitor (option D): by the time liquefaction is visually apparent (sloshing sounds, list developing), it may be MINUTES from capsize. "Counter-ballasting" an actively liquefying cargo hold does not address the flow of liquid cargo within the hold. This response would likely cause rapid capsizing. The only safe response to Group A cargo safety doubts is to resolve them BEFORE loading.

Question 2

Before departure from Durban, your stability program shows the vessel meets 5 of the 6 IS Code criteria but the righting lever arm at 30° (GZ at 30°) is 0.18m against the required minimum of 0.20m. What do you do?

Accepted Answer

IS CODE CRITERIA — GZ AT 30° DEFICIENCY: THE SIX IS CODE CRITERIA (MSC.267(85) — IS Code 2008): the International Stability Code mandates SIX stability criteria that ALL must be satisfied: (1) Area under GZ curve from 0° to 30° ≥ 0.055 m·rad; (2) Area under GZ curve from 0° to 40° ≥ 0.090 m·rad; (3) Area under GZ curve from 30° to 40° ≥ 0.030 m·rad; (4) GZ AT 30° ≥ 0.200m; (5) MAXIMUM GZ at angle ≥ 25°; (6) GM₀ ≥ 0.150m. FAILING ONE CRITERION MEANS FAILURE: all six criteria must be satisfied simultaneously. A GZ at 30° of 0.18m (vs required 0.20m) is a FAILURE — the vessel does NOT meet IS Code intact stability criteria. THE VESSEL CANNOT DEPART: it would be UNSEAWORTHY for the intended sea voyage. REMEDIES — HOW TO CORRECT THE DEFICIENCY: (1) REDUCE CARGO: if cargo is high in the vessel, shifting weight lower increases the GZ at 30°; (2) LOWER THE G: reduce KG by: (a) Adding low ballast (double bottom tanks); (b) Removing top-heavy weights; (c) Shifting cargo lower; (3) INCREASE BEAM LOADING: for certain hull forms, a different loading pattern affects the GZ curve shape; (4) REDUCE FREE SURFACE: if slack tanks are contributing to reduced GM — fill or empty tanks to remove free surface effect; DOCUMENTATION: the master must not sail with a stability calculation showing non-compliance. This is ISM non-conformity — notify DPA. LEGAL: departure with known stability non-compliance = MSA 1995 Section 58 offence (taking an unseaworthy ship to sea). IS Code — mandatory treaty obligation: the International Stability Code (IS Code 2008, MSC.267(85)) is mandatory under SOLAS Regulation II-1/5-1. It is not guidance — it is a mandatory standard with which ALL ships must comply. Failing ONE criterion fails ALL six — they are not averaged. "Close enough" margin (option B): there is no concept of "within tolerance" for IS Code criteria. The 0.20m GZ at 30° is a minimum — not an average. A calculated value of 0.18m is non-compliant. Stability programs have their own accuracy considerations — but if the calculation shows 0.18m, the vessel is non-compliant and must be remedied before departure. Charterer responsibility (option C): the charterer prescribes the cargo but the MASTER is responsible for the stability of the loaded vessel. The master must assess the proposed loading plan and refuse to sail if the result is non-compliant. The master can agree with the charterer to adjust the loading to achieve compliance (different stowage, reduced quantity, added ballast) — but the master cannot blame the charterer for a stability failure. IS Code as guideline (option D): this is completely incorrect. The IS Code is cited in SOLAS and is a mandatory instrument for all flag states that have ratified SOLAS. It is enforced by flag state surveyors, classification societies, and PSC inspectors. A vessel that departs without meeting IS Code criteria is unseaworthy in law and the master faces criminal liability under MSA 1995 Section 58. What "GZ at 30° ≥ 0.20m" means physically: GZ is the righting lever — the horizontal distance between the line of action of buoyancy and gravity at a given angle of heel. A GZ of 0.20m at 30° means the restoring couple (GZ × displacement) is providing a meaningful self-righting force at that angle. Below 0.20m, the vessel has reduced ability to recover from a 30° heel — which in heavy weather could develop into capsize.

Question 3

Your vessel is listing to starboard at a steady angle of approximately 8°. The deck officer believes this is a list due to off-centre cargo but the second officer suspects angle of loll. How do you distinguish, and what are the correct actions?

Accepted Answer

ANGLE OF LOLL vs LIST — IDENTIFICATION AND RESPONSE: DISTINGUISHING FEATURES: (1) LIST (caused by off-centre weight): (a) The vessel rests to one side; (b) GM is POSITIVE; (c) The GZ curve is displaced sideways but still positive; (d) Filling a tank on the high side (away from the list) will CORRECT the list; (e) The vessel has a definite "preferred" upright position but is offset by the asymmetric loading; (2) ANGLE OF LOLL (caused by NEGATIVE GM): (a) The vessel has ZERO or NEGATIVE GM; (b) The GZ at zero degrees is ZERO; (c) The vessel has no stable upright position — it lolls to one side where the GZ curve has positive values; (d) The vessel may flop between loll to port and loll to starboard; (e) IDENTIFYING CHARACTERISTIC: if you forcibly push the vessel further to the loll side — it continues to heel further. If you push a listed vessel — it resists and returns; HOW TO DISTINGUISH ON THE VESSEL: (1) Look at the GZ curve from the loading computer: is GM positive (list) or zero/negative (loll)?; (2) Apply a small external force: does the vessel resist (list) or comply (loll)?; CORRECT ACTION FOR LOLL: (1) DO NOT FILL HIGH-SIDE DOUBLE BOTTOM TANKS FIRST: the counter-intuitive nature of loll. Adding ballast on the high side RAISES the centre of gravity FURTHER — makes GM MORE negative — the loll worsens. The vessel may VIOLENTLY FLOP to the opposite side; (2) CORRECT ACTION: add ballast SYMMETRICALLY to the LOWEST point first. Fill lowest double bottom tanks evenly port and starboard to lower G and raise GM above zero; (3) NOTIFY DPA: this is a serious stability situation. Why high-side ballasting is FATAL in angle of loll: this is the most counter-intuitive and critical point in the angle of loll topic. At angle of loll with negative GM: (a) Adding ballast to the high side raises G because the ballast centre is higher than the vessel's current G; (b) This makes GM MORE negative; (c) The loll worsens; (d) Suddenly adding water to a high-side tank when GM is negative can cause the vessel to VIOLENTLY FLOP to the other side through the unstable upright position; (e) The violent flop has caused capsizes and cargo losses in practice. The asymmetric ballast (option D): cross-flooding from the loll side to the high side raises G on both sides. If the cross-flooding ALSO raises G (because the tanks are above the existing G) — it makes things worse. The principle remains: lower double bottom tanks first, symmetrically. The violent flop: at an angle of loll, the vessel is in stable equilibrium AT the loll angle. As you correct the negative GM (by adding weight low down), there is a brief period where the vessel passes through UNSTABLE equilibrium at the upright position before developing positive stability. During this passage through zero stability, ANY external force (wave, wind) can cause a rapid angle change. The vessel may flop to the other loll angle. Crew and cargo must be secured during the corrective process. 8° list is acceptable (option C): a static 8° list at sea is NOT acceptable and is not normal. It indicates either asymmetric loading (which should be corrected) or reduced stability (angle of loll — which is dangerous). Any unexpected and persistent list requires investigation and correction.