This incident information refers to loss of main electrical power onboard a bulk carrier and while at sea. The vessel had completed heavy weather preparations on deck, when she approached a forecasted storm with force 8-9 and waves up to 7 metres. Shortly after running into the storm the fire alarm sounded, a black out occurred and the main engine stopped.
It was reported to the master that a considerable amount of water had entered the upper deck alleyway and dripped down from the panels above and into the main switchboard. The cleaning up operation before resuming the voyage was estimated to be at least 24 hours, and thus a tug boat was requested. Electric power was resumed some 24 hours after the blackout, and the vessel returned to the port of departure some 36 hours later.
Damage was limited to main switchboard components.
The vessel had sustained flooding of the accommodation cross alleyway via the starboard side accommodation door on the upper deck. The water had flooded the electrical workshop on the upper deck and drained down to the engine control room through deck penetrations for electrical cables (A-0 boundary, see picture above) and into the main switchboard.
The probable cause for the total loss of power was contributed to sea water entering into the main switchboard through the upper deck.
Regarding the main switchboard; the top of each section was fitted with a tray and a small drainage hole on the outboard side, see pictures below. Water remaining in this area was able to drain down between sections and into the switchboard. With a small list to starboard the water was able to run down the front of switchboard.
Photo above: Tray above the switchboard.
Photo above: Tray with drainage hole.
In addition, there was no division of the main bus-bars, had this been the case then it may have been possible to isolate the wet part of the switchboard and resume operation earlier.
Lessons to be learned
- Indication should be provided to show status of weather tight doors, or crew procedure to be established for reliable reporting “all doors closed” during periods of bad weather.
- Cable penetrations through the upper deck should be given more attention during class surveys, and during inspection by ship’s crew.
- If the different spaces are ventilated, it may be easy to check such penetrations for leakage, due to differential pressure.
- Required ingress protection (IP) rating of switchboards should be observed.
- Details of the top of the switchboard should be investigated, to prevent retention of water and eventual leakage into the switchboard.
Source: DNV
Officer of the Watch 
Leave a Comment