Your vessel is loading containers. You receive notification that one container is 2MT heavier than declared on the booking note. The container is already loaded in a high stack. What are your obligations?

A. OVERWEIGHT CONTAINER — CSS CODE AND VGM OBLIGATIONS: SOLAS VI/2 — VERIFIED GROSS MASS (VGM): since 1 July 2016, the VGM of all packed containers must be verified by the shipper before loading. The VGM can be determined by: (a) Method 1: weighing the packed container on certified scales; (b) Method 2: weighing all cargo items individually plus the tare weight of the container. THE VGM MUST BE PROVIDED TO THE MASTER OR SHIPPING LINE before the container can be loaded. A container without VGM cannot be loaded legally. OVERWEIGHT SCENARIO — 2MT DISCREPANCY: a 2MT discrepancy means the container is 2MT heavier than declared. This affects: (1) STACK WEIGHT LIMITS: the deck has structural deck strength limits (tonnes per unit area). A heavier container in a high stack increases the compression load on lower containers and the deck. May exceed structural limits; (2) LASHING LOADS: the CSS Code calculates lashing forces based on container weights. An undeclared 2MT may result in lashing forces exceeding the lashing capacity (typically rated to Racking Force standards); (3) STABILITY: the heavier container changes the vessel's loading condition — affecting trim, list, and GM calculation. The stability calculation must be re-run; MASTER's OBLIGATIONS: (1) NOTIFY THE TERMINAL: immediately. The container location in the stack must be assessed by the ship planner; (2) REASSESS STABILITY: re-run the loading computer with the correct container weight; (3) CSS CODE ASSESSMENT: verify that deck strength and lashing capacity are not exceeded with the corrected weight; (4) CONSIDER RELOCATION: if the container in a high position exceeds stack or lashing limits — relocate to a lower tier or different bay; (5) DO NOT SAIL: if the assessment shows structural or lashing limit exceedance — the container must be relocated before departure.

B. A 2MT discrepancy is within the normal tolerance for container weights. Accept the container and proceed to departure.

C. The shipper is legally responsible for the declared weight. Load the container as planned and seek compensation from the shipper for any problems.

D. Remove the container from the stack immediately. Overweight containers must be discharged before any departure regardless of location or assessed impact.

A. 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).

B. The vessel is close enough to the 0.20m requirement. A margin of 0.02m is within normal calculation tolerance and the vessel can depart.

C. Consult the charterer. As the cargo interests are driving the loading plan, the charterer is responsible for stability compliance.

D. Only the stability program minimum acceptable values matter for commercial voyages. IS Code criteria are guidelines, not mandatory requirements.

A. 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.

B. Fill the high-side (port) double bottom tanks immediately. Adding ballast to the high side always corrects any form of list or loll.

C. An 8° list at sea is normal and acceptable. No action is required unless the angle increases beyond 15°.

D. Open the cross-flooding valves to transfer ballast from the starboard to the port tanks. Cross-flooding always corrects asymmetric stability issues.