The National Transportation Safety Board on Tuesday released its preliminary report on the March 26 crash of the Dali cargo ship into Baltimore’s Francis Scott Key Bridge.
Around 0125, the vessel Dali experienced a critical electrical failure about 0.6 miles from the Key Bridge. Two electrical breakers tripped, causing a blackout that disabled shipboard lighting, equipment, main engine cooling water pumps, and steering gear pumps. Although generators 3 and 4 continued to run, the main propulsion engine shut down due to the loss of power to necessary pumps, and the vessel lost steering capabilities.
At 0126, the voyage data recorder (VDR) resumed recording data, indicating the ship's heading and course had slightly changed, and speed had decreased. The senior pilot, having taken control, ordered a 20° port rudder, and the emergency generator started, providing limited power for emergency equipment, including a slow-moving emergency steering pump.
The crew manually restored power by closing the tripped breakers, but at 0.2 miles from the bridge, a second blackout occurred. The emergency generator maintained power to emergency systems, and generator 2 automatically started, restoring power to the HV bus. The senior pilot ordered the rudder hard to port at 0127:23, but the lack of propulsion hampered steering efforts. Despite the crew regaining electrical power before the ship struck the bridge, they were unable to restore propulsion.
The cost saving measures that caused this was not having tug escorts to the far side to the bridge. Two appropriately sized tugs could have stopped or turned the boat without a problem.
The emergency generator is just there to power absolute emergency equipment: some lights, radio, onboard communication, stuff like that. Not for powering the whole ship. For that there are the main generators, of which that ship has four, and you need several of them running to actually do something.
The emergency generator is something the size of a trucks' engine. The main generators are more like the size of trucks.