Swedish Club’s recently-released casebook describes an incident where maintenance job onboard bulk carrier led to flooding of the engine room.
The case
The engineers on a bulk carrier were carrying out scheduled maintenance on one of the ballast pumps.
They had closed all the isolating valves to the ballast pump and put up notices about the job in the engine room and engine control room, but not on the bridge. They didn’t finish the job on the first day, so continued the next day.
Preparing for port state inspection
The following day the Master asked an officer to print out the alarm list for the ballast water management system before arriving at the next port, as a port state inspection was expected.
To get the list the officer had to start the ballast water management system, which he did.
The bilge high level alarm was suddenly activated in the engine room. An oiler checked the bilges and could see water pouring in, covering the tank top. An engineer turned off the power to the ballast water management system.
He also found out that two ballast system valves were open from the main seawater crossover suction line. He closed these valves immediately to stop the ingress of the water. These valves had been opened automatically when the ballast water management system was started. The engineers pumped the water from the tank top into the bilge holding tank.
Water in the lubrication oil
One hour later the main engine bearing wear alarm – ‘water level 50%’, went off. The main engine system lubrication oil was found to have 0.09% water content. The second lubricating oil purifier was started.
A couple of hours later the main engine bearing wear alarm went off once again. A second sample of the lubrication oil was taken, and it was found that the oil had 0.08% water in it.
The Chief Engineer decided to partially change 3,000 litres of lubrication oil in the system. Afterwards a third sample was taken and the water content was 0.019%.
The engine was stopped, and a full change of the lubrication oil was completed. A crosshead bearing was opened for inspection. No damage was found. However, one of the rubber diaphragm seals for draining the crankcase to the system lubricating oil tank was found to be defective. This had caused the water flooding into the engine room to contaminate the lube oil.
Severe engine problems through voyage
The main engine was restarted, and the voyage resumed. The main engine was an electronic controlled model i.e. the exhaust valves and fuel injection system were powered by hydraulics. The system lubrication oil was used as a hydraulic medium.
The following day there were problems with some hydraulic components and the main engine had to be stopped. A couple of cylinder units and pumps had to be dismantled, cleaned and reassembled. The main engine could not be restarted because of low hydraulic pressure.
It was decided that one of the cylinders had to be blanked off. The main engine was started and stopped several times over a number of days as the hydraulic system was leaking.
Because the engine was running on low rpms, the scavenge trunking became fouled with oil deposits, so the engine had to be stopped several times and the trunking had to be cleaned.
Because water contaminated the lubrication oil there was serious damage to several crosshead bearings, crosshead pins, main engine cylinders, hydraulic pumps and main engine turbo charger bearings.
Lessons learned
- A proper risk analysis should always be carried out before any repairs/maintenance, especially if the affected system is complicated and can be controlled from different locations.
- It is also worth considering physically disconnecting power to components so they cannot be activated accidently during the repair/maintenance.
- It is essential that the bridge and engine crew discuss all jobs that can affect each other’s department. If a job on the ballast system is planned, the bridge need to be informed and if the job is extended to the following day the OOW needs to be informed. The OOW has to ensure that this information is written clearly and discussed during the watch handover.
- If there are excessive quantities of water on the tank top there is a risk that this will enter the main engine sump tank via a defective diaphragm and subsequently contaminate the main engine lubricating oil system, resulting in severe damage to the main engine components.
- If heavy contamination of water is found in the system: (i) the lube oil in the sump tank must be transferred to a settling tank. (ii) the sump tank and crank case should be cleaned. (iii) a complete fresh oil change filled to the level recommended by the engine manufacturer.
- It is recommended that all diaphragms are replaced every five years in connection with the vessel’s special survey.
- The exchange of rubber diaphragms should be included in the vessels PMS system.
- It is recommended to owners that spare diaphragms are kept on board at all times, in addition to enough system lubrication oil to completely replenish the system.
EXPLORE SWEDISH CLUB CASEBOOK HERE
