Hold fire with an oxidiser in the stow
MV Kestrel Bay, a container ship, is 800 nm from the nearest SAR unit at 0340 when the fixed fire detection system alarms for No.2 cargo hold. Smoke is issuing from the hold's ventilation louvres and there is a strong smell of chlorine. The stow plan shows 40 boxes in the hold, including six units declared as UN 2880 calcium hypochlorite (Class 5.1) in the second tier, and general cargo including bagged copra in the same hold. The hold's fixed CO2 system is charged and the hold is fitted with a smothering system, but the ventilation flaps are still open. One able seaman who went forward to investigate is unaccounted for. Wind is SW force 5, sea moderate, the ship is making 12 knots.
1. Set out the master's actions for the first 20 minutes, including how the missing seaman is handled.
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The first 20 minutes decide the outcome, and there are three competing demands: the missing man, the fire, and the ship.
- Sound the general alarm and muster - all hands to emergency stations, head count taken at the muster point. That head count is what defines the search: if the able seaman is genuinely missing, you know roughly where he was sent.
- Stop the ship and turn to put the smoke and any toxic gas plume aft and to one side; reduce to minimum steerage way. A 12-knot wind over the deck turns the whole forward area into a gas hazard.
- Search, but only where a man could be. Two BA teams, lifelines, radios, from the accommodation forward along the weather side. The hold itself is not entered - a closed hold with a fire in it and chlorine present is a lethal space and will not be opened for a search. Check the deck lockers, the forecastle, the hatch access trunk and the paint store; the AB most likely went to the louvres, not inside.
- Close and seal the hold: stop ventilation, shut the flaps and the access, and confirm the sealing from outside. Ventilation feeds the fire and discharges chlorine into the ship.
- Boundary cooling on the deck above and the bulkheads of the adjacent spaces, with hoses laid out but no water into the hold.
- Bridge and reporting: position, weather, ETA to the nearest suitable port, and a distress or urgency message as the situation develops. Inform the company DPA.
The search and the sealing are not in competition for long: a fire of this type does not permit entry, so the search is finished within 10 to 15 minutes either way.
2. Should the fixed CO2 be released? Reason through the cargo.
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The instinct is to release, and it will probably be the wrong call. Work through what the CO2 is supposed to do.
Smothering works by removing oxygen. Calcium hypochlorite is a Class 5.1 oxidiser: when heated it decomposes and releases oxygen of its own, and the decomposition is strongly exothermic. A fire in an oxidiser does not stop for lack of oxygen, because the cargo supplies it. Worse, the hypochlorite will continue to react with the copra and any other combustible in the hold, and will generate chlorine and heat regardless of the atmosphere.
So the honest position is:
- CO2 is at best ineffective and at worst wastes the system on the oxidiser. It may still suppress the parts of the fire involving copra alone, which is a reason to consider it, but it cannot be relied on to extinguish the seat of the fire.
- Water is worse. Water on hypochlorite liberates chlorine and heat; water in a deep-seated hold fire adds weight, free surface and stability problems. Do not flood.
- Closing and sealing remains correct, because it limits oxygen to the copra, keeps the chlorine inside the hold and protects the crew, but it will not end the reaction.
- Do not open the hold to investigate, and do not send anybody into the hold under any circumstances.
The defensible decision is: seal the hold, boundary cool, monitor the bulkhead temperatures, keep the crew clear, and treat the ship as having a fire that will burn until the oxidiser is consumed. Release the CO2 only if the assessment is that the copra fire is the principal fire and the bundle is intact - and record the reasoning either way.
3. Ten hours later the deck above No.2 hold is hot to the touch and the bulkhead temperature is still rising. What are the options and how is the decision made?
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A rising bulkhead temperature after ten hours means the fire is still consuming cargo and the containment is losing. Heat through a deck is a structural problem before it is a firefighting problem: steel loses strength above roughly 500 °C, and the deck is carrying the ship's hull girder.
The master's options, honestly stated:
- Continue as is and hold course for a port 30 hours away. Acceptable only if the temperature trend flattens and the boundary cooling can hold the deck below about 150 to 200 °C on the far side.
- Divert to the nearest suitable port or sheltered water, which shortens the exposure and puts tugs, shore fire services and a place to beach within reach. Generally the best option once a hold fire is not being extinguished.
- Rendezvous with a salvage tug able to apply monitors and, if necessary, take the ship in tow.
- Prepare to abandon, which means mustering the crew, briefing the lifeboat and life-raft parties, ensuring the EPIRB and SART are ready, and getting the abandon decision to a defined trigger - for example, deck plating glowing, a bulkhead failure, or water reaching the accommodation.
Decision process: keep a running temperature log at fixed points, plot the trend, and set a written trigger point in advance so the decision is not made in the middle of a crisis. Address the stability side as well - firefighting water on deck and in the hold is weight high up and free surface; the loading computer should be updated with the actual water usage. Consult the company and, through the RCC, a salvage master. The master decides, but the decision should be evidence-based, recorded, and taken early rather than late.