Scavenge space fire with the ship committed to a narrow channel
At 0240 the duty engineer wakes you in the cabin next to the control room. On the 10-cylinder, 9,500 kW slow-speed main engine burning HFO at 72 rpm, No. 7 unit exhaust gas temperature is 415 °C against a 350 °C mean, scavenge air temperature is rising, and the turbocharger has surged twice under steady load. There is a smell of scorching paint and sparks are spitting from the No. 7 scavenge drain cock. He proposes to stop the engine immediately and pull the No. 7 scavenge space doors within ten minutes.
The tanker is deeply laden at 13.2 m draught, making 11 kn, with the pilot aboard and 2 nm to a 45° fairway alteration in a channel of 14.5 m depth. The Chief Engineer has been on duty since 0600 and is asleep. A fixed steam smothering system protects the scavenge spaces.
1. What is your diagnosis and what do you do in the first ten minutes, including whether the engine may be stopped where she is?
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Diagnosis. A single unit with a sharply raised exhaust temperature, rising scavenge air temperature, turbocharger surging and sparks/burning smell at the scavenge drains is a scavenge space fire - burning cylinder lubricating oil and carbon deposits in the scavenge air space, usually fed by a leaking piston rod stuffing box or a sluggish/scuffed liner.
First actions.
- Inform the bridge, the master and the pilot at once. A stopping or slowing decision is a bridge decision here; the pilot needs to know before the alteration 2 nm ahead.
- Do not stop the engine dead in the channel. With 13.2 m draught in 14.5 m of water and a turn two miles ahead, loss of power and steerage is a greater immediate danger than the fire. Reduce to a load the engine will carry comfortably and keep her turning, which carries heat out of the space.
- Cut the fuel to No. 7 unit only - lift the pump - and run on the remaining nine cylinders.
- Increase cylinder lubrication to the affected unit to limit liner scuffing while it runs dry, and keep the scavenge drains open and discharging, watching for a change from oil to sparks.
- Line up and be ready to apply steam to the No. 7 scavenge space; apply it if the fire does not die down within a few minutes of the load reduction.
- Watch the crankcase oil mist detector and the under-piston space temperatures closely. Oil mist means the fire has reached the crankcase and everything changes.
- Ask the bridge for the earliest safe place to stop - typically once the alteration is completed and the vessel is in the wider reach or the roads.
By the time the Chief Engineer arrives, the engine is running on nine units, the steam line is lined up, and the decision to stop has been deferred for a defined short period on the bridge's authority - not ignored.
2. The Chief Engineer applies steam, the fire dies, and he announces he will stop the engine and open the scavenge doors to inspect. What is your response?
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The doors do not come off yet. The fire is out only because the air and fuel have been cut off. The scavenge space is still at several hundred degrees and soaked in hot oil. Opening the doors admits a rush of air into a hot space with oil residues present - the classic flash or re-ignition scenario, and a serious burn risk to anyone standing at the door. The metal can also distort as it cools unevenly.
Sequence.
- Stop the engine only when the bridge confirms the vessel is clear of the channel and can be handled on the remaining units or tugs.
- Keep the main lubricating oil pump running and keep the cooling water circulating; do not let the engine soak.
- Keep the steam applied as a blanket until the space has been allowed to cool at a controlled rate, with the drains open and the drain cock monitored.
- Once the space has cooled well below the oil flash point and no heat soak is evident, and only with the Chief's and master's agreement, slacken the doors cautiously with a fire hose, extinguishers and a BA team standing by.
- Then inspect the piston rod, stuffing box, liner and scavenge ports to establish the source, and test the crankcase oil mist detector before restart.
The wider risk. Before any of this I insist the crankcase is checked for oil mist and temperature. A scavenge fire that has disturbed the stuffing box can pressurise the crankcase and a secondary crankcase explosion is the event that kills engine room staff. If the oil mist detector alarms, the engine stops, everyone leaves the space, and the crankcase doors stay shut until it has cooled and the atmosphere is proven safe. On a tanker at anchor the deck side also needs warning if the uptake is hot.
3. The Chief Engineer has had 20 hours on duty in the last 24. What STCW limits bear on this, and how do you manage the emergency team?
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The rule. STCW Regulation VIII/1 and Section A-VIII/1 require a watchkeeper to have at least 10 hours of rest in any 24-hour period and 77 hours in any seven-day period, divided into no more than two periods, one of which is at least 6 consecutive hours, with no more than 14 hours between consecutive rest periods. The 10 hours may be reduced to not less than 6 consecutive hours only in exceptional circumstances, for no more than two days, not consecutively, with equivalent compensatory rest and a seven-day gap before the next reduction. The Chief Engineer at 20 hours on duty has almost certainly exceeded the rest requirement and is a fatigue casualty in the making.
How I manage it.
- I say so plainly and early: fatigue is a recognised contributing factor in engine room fires and to a Chief Engineer making a snap decision to open scavenge doors at 0300.
- I have the Second Engineer, the ETO and the day-work fourth called; the immediate tasks are delegated - the Second holds the manoeuvring platform and monitors temperatures, the ETO checks the alarm and oil mist detector circuits, the duty engineer keeps the records.
- The Chief retains the decision on the machinery, but he is told that he is relieved at 0600, and I ensure he is.
- I want the hours of rest records updated contemporaneously, because the alarm, the temperatures and the manning pattern will all be examined if this becomes an insurance or flag State matter.
Fatigue is also a finding: if the ship is chronically short of engineers, that is a reportable resource and mustering issue to the company, not just a bad night.