Stability After Heavy Cargo Loading in Port
A general cargo ship is loading steel coils in port. The loading plan shows 1,200 tonnes of coils stowed in the lower hold and 300 tonnes on deck. The vessel's initial metacentric height (GM) is calculated at 0.35 m, and the master is concerned about stiffness. The deck cargo is secured with lashings, but the weather forecast predicts 25-knot winds and 2-metre seas for the next 24 hours. The vessel's freeboard is reduced by the deck cargo, and the load line marks are close to submersion. The chief engineer is asked to advise on the stability and loading plan before departure.
1. How would you assess the vessel's stability and the loading plan, and what advice would you give the master?
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Assessment: A GM of 0.35 m is low for a general cargo ship, indicating a stiff or tender condition depending on the actual GM. The deck cargo raises the centre of gravity and reduces freeboard, increasing the risk of water ingress and loss of stability in heavy weather. The load line marks being close to submersion means the vessel may be overloaded or have insufficient reserve buoyancy.
Advice:
- Recalculate the stability with the actual weights and centres of gravity, including the deck cargo and any ballast. Verify GM against the minimum required by the stability booklet and the International Grain Code if applicable.
- Consider reducing deck cargo or redistributing weight to lower the centre of gravity.
- Check the load line and freeboard; do not depart if the marks are submerged or if reserve buoyancy is inadequate.
- Secure deck cargo to withstand the forecast conditions, and consider delaying departure or seeking shelter if stability is marginal.
- Document the stability calculation and the master's decision.
2. What would you do if the master insists on departing despite your concerns?
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Action: Clearly state your concerns in writing, including the calculated GM, freeboard, and forecast conditions. Recommend a specific alternative, such as reducing deck cargo or adding ballast. If the master still insists, document the advice and the master's decision in the official log and notify the company's marine superintendent. The master has overriding authority for safety, but the chief engineer's professional duty is to ensure the concerns are recorded. Do not falsify stability records. If the vessel is clearly unseaworthy, consider notifying the flag state or class as appropriate.