Know Your Ship
Report No. 200236
Location:
River Elbe. Weather: Cold, no wind, good visibility, still dark. Crushed ice encountered since Brunsbuttel.
This case looks like an engineering issue but it is not. It is essential that all crew have a good understanding of the onboard emergency electrical system. It is important because the emergency switchboard and generator are located away from the engine room and are sometimes exposed. The emergency generator is a vital part of ship's safety equipment and it is the most vulnerable engine onboard. That is why Port State Control Inspectors always look at the emergency generator room.
Own vessel was a 23,000grt, four year old container ship. We had a river pilot onboard and were sailing at half manoeuvring speed (9 knots), heading 098°T. The crew were rigging the pilot ladder to receive the Hamburg dock pilot and preparing to make fast the tugs.
All systems and equipment were working normally, with the exception of the auxiliary engines - the cooling water temperature on these was slightly high due the inlet boxes being blocked with ice (the local temperature was 7 degree Celsius below zero).
At 0700 UTC whilst still dark, all electric equipment on the ship's bridge went off. The Captain and all the bridge team thought the ship had a complete electrical break down due to the auxiliary engine overheating. The ship started moving to port heading towards several boats and small ships leaving Hamburg. The Master called the AB on deck with the VHF portable radio. The AB did not hear because the radio was on the deck whilst he was preparing the gangway to embark the harbour pilot. The Master then sent the helmsman to the bow to drop anchor as requested by the river pilot. The master moved to the starboard side wing in an attempt to hear the emergency generator start. The emergency power would have allowed the ship to have the steering gear control available and so to avoid the outbound vessels. Instead of hearing the emergency generator, the Master heard all engine room fans working. Looking forward, the Master could see all reefer container lights on, showing the reefers were still working. The AB, on his way to the bow, called on the radio and asked if he could return to bridge as the ship was no longer without power. The master looked into the wheelhouse and saw everything still without power except the coffee pot. He called the engine room and the Chief said everything was OK - "only some lights switched off" - the main engine was still working on half manoeuvring speed ahead!
The master ordered the engine to be stopped and informed the pilot that the engine was still working and available for use. The Pilot requested full astern and the order was passed to the engine room. The Master then called the ship's electrician on the Public Address System and ordered that he should go to the emergency switchboard at once!
The electrician found the emergency switchboard off and the emergency generator sounding as if it was trying to start (making an air whistling sound). One circuit breaker on the emergency switchboard was half tripped (tried to trip and got jammed). The circuit breaker on the main switchboard was also tripped. This breaker was the supply from engine room to the emergency switchboard (similar to most of the standard SOLAS vessels of that size). Later on, it was discovered that the breaker in the main switchboard was tripped due a large short circuit on the connection box to one deck motor (combined blower/exhaust motor from engine room designed to vent the engine room after opening the CO2 in the engine room). It tripped because the motor controller had overheated and jammed. The emergency switchboard breaker for that motor had overheated and jammed as well.
Around 0710 UTC the electrician manually opened the jammed breaker on the emergency switchboard and closed the breaker on the main switchboard. The electric power was then restored to the bridge but the ship already had gone aground three or four minutes previously. Fortunately we had managed to avoid colliding with any of the outbound ships. The grounding occurred due to the bow swinging to starboard with the engine full astern (ship had fixed propeller, right handed), attempting to avoid colliding with other ships and moving the bow slowly towards the bank on the ship's starboard side.
No structural damaged was suffered and all tank soundings indicated no apparent ingress of water, no flooding, and external observations indicated no apparent pollution. The next day the ship was floated off the bank on the high tide using her own engine after removing a lot of the ship's ballast and most of the fresh water.
Lessons to be learned
Never forget that your emergency switchboard is always on and ready to feed the more important systems in the ship. What can change is the source of the power. Most of the time the power comes from the main switchboard in the engine room. In an emergency situation, the emergency generator starts and supplies the power to the emergency switchboard, which supplies almost everything on the bridge except the coffee pot. When you have a short circuit on the bus bars of the emergency switchboard, or equipment connected to it, the emergency switchboard will be disconnected from the engine room, and the emergency diesel will try to start at once and will be automatically prevented from starting by the switchboard due the short circuit on the emergency bus. All crew must be aware that the time is too short to understand what is happening and to decide on the best action to take.
On most ships (tankers excepted), when the emergency switchboard goes off, only one steering gear pump will be switched off. Together with that pump, all steering electric controls from the bridge will also turn off (these controls are supplied through the emergency switchboard). The other pump that receives power from the main switchboard will still work but it will need a member of the crew to press the solenoid valve hand device in the steering gear room to turn the rudder (that's why any professional crew has a wooden stick in the steering gear room). For this reason SOLAS requires two alternative means of communication between the bridge and the steering room (sound powered or battery powered).
The ship's battery powered lights (provisional electrical system) are not on when the main lights are on, even with the emergency switchboard switched off. Most of the lights below deck will remain on because they receive electric power from the main switchboard.
Make sure that the crew understand (using the most suitable means) that any light with a red dot or a red circle means that the light is supplied through the emergency switchboard. When those lights are out it can mean there is a hell of a problem.
Some emergency lights are battery powered so (4) might not apply in all cases. Fortunately this incident did not result in a collision, however a grounding can still ruin your whole day. It is very helpful to learn which power source supplies which vital equipment and what can happen when things go wrong. Lists and schematic diagrams can assist in this.
Source article nautinst.
