Suspected Ballast Tank Flooding and Rising List
At 04:20, a 28,000 dwt bulk carrier loaded with 26,500 t of iron ore in Nos.3 and 4 holds is in Beaufort 7, 180 nm from Cape Finisterre. The No.1 starboard water ballast tank sounding rises from 0.8 m to 3.4 m in 50 minutes. Drafts show the starboard side immersed 0.35 m more than port, list 4° starboard and slowly increasing. No.1 hold bilges are dry. The collision bulkhead is intact 14 m forward of No.1 hold, and No.2 port ballast tank is part loaded. The loading computer shows GM 1.45 m before flooding, but the damaged-stability module is not approved for this condition. Wind is on the starboard beam at 28 knots. The nearest port is 11 hours away; a coastal shelter is 4 hours away. The master asks whether to counterflood No.2 port ballast tank and whether to alter course.
1. What is your stability and damage assessment, and what immediate actions do you order?
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The rising No.1 starboard ballast tank sounding, starboard list, and starboard-side immersion indicate uncontrolled flooding into that tank or an adjacent space. Dry No.1 hold bilges are reassuring but do not exclude a breach into the ballast tank itself. The pre-flood GM of 1.45 m is not a damaged GM; flooding adds weight low but also creates free surface and may reduce reserve buoyancy. Because the damaged-stability module is not approved for this condition, I would treat the vessel as having uncertain residual stability.
Immediate actions: muster damage control, sound all tanks and holds, check the collision bulkhead and tank boundaries, close watertight doors, and reduce speed to limit slamming and ingress. Alter course to put the wind and sea more astern or on the port bow, reducing beam wind and rolling. Do not counterflood yet. Prepare pumps and damage-control materials, inform the company and MRCC/coast radio as appropriate, and calculate residual GM and list using the approved booklet and manual methods.
2. Would you authorize counterflooding No.2 port ballast tank?
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Only conditionally. Counterflooding can reduce list, but a part-loaded No.2 port tank would add free surface unless pressed completely full. It also adds weight and reduces reserve buoyancy, which is dangerous when the damage extent is unknown. I would not authorize it merely because list is 4°. First calculate the effect on damaged GM, drafts, freeboard, and reserve buoyancy. If the list is increasing toward 7–10°, the weather deck is threatened, and calculations show acceptable residual GM and freeboard, fill a low port-side tank completely-not partially-and monitor list, drafts, and sounding hourly. If calculations are uncertain or reserve buoyancy is marginal, do not counterflood; reduce speed, head for shelter, and prepare to abandon if list becomes uncontrollable.
3. What route and reporting decision do you make?
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Choose the 4-hour coastal shelter if the list continues to increase, the sounding rise cannot be controlled, or weather is worsening; shelter reduces exposure and allows closer damage inspection. If the list stabilizes and residual stability is confirmed adequate, proceed toward the nearest port at reduced speed, keeping the shelter as a fallback. Report to the company, flag/class, coastal state, and port authority, stating the flooding, list, drafts, GM uncertainty, and intended route. Keep the master informed for a possible distress call. The key judgement is that distance alone does not decide the route; rate of change of list and confirmed residual stability decide it.