The company is building the 'USNS Miguel Keith', a new Expeditionary Sea Base (ESB) to join the US Navy’s Military Sealift Command.
In an official statement to local media, the shipbuilder informed that the dock, used to support the ship, is currently under construction.
There were no injuries and the ship is safe and in stable condition, the company added. An assessment is underway to determine the extent of the impact to the ship.
The incident left a big mess of debris in San Diego Bay, according to CBS News 8.
The cause of the incident is unknown, but media suggestions indicate failure of the dry dock wall caused an ingress of water from the Bay.
The following video posted by NASSCO in early June shows putting of the final block of ESB 5: