Video footage shot on the container ship that flattened a section of the Francis Scott Key Bridge in Baltimore shows the extent of damage.
The National Transport Safety Board (NTSB) video is one of the first glimpses inside the Maersk-chartered 9,962-teu Dali (built 2015).
There are close-ups of debris on the bow, as US Coast Guard and NTSB officers take photos and temperature measurements.
Buckled deck structures are visible and what appear to be storage drums crushed beneath the metal of the bridge sections that fell on to the post-panamax.
There is also concrete rubble on the deck.
Investigators are later shown downloading information from the voyage data recorder on the bridge.
The audio has been removed from the footage.
The NTSB said Baltimore port has now established a second temporary alternative channel on the southwest side of the main channel.
This will be for “commercially essential vessels”, but deepsea ships still cannot exit the port.
The new channel has a controlling depth of 14 feet (4.27 metres), a 280-foot horizontal clearance and a vertical clearance of 124 feet.
Milestone in response effort
“The opening of these two alternate channels and transit of critical response resources, as well as the first commercial traffic movements through the area, is a significant milestone in our response efforts,” said US Coast Guard commander Baxter Smoak.
“Our number one priority remains the opening of the deep-draught channel. We are simultaneously focused on opening additional routes of increased capacity as we move forward.”
A tug pushing a fuel barge become the first ship to pass the collapsed bridge on Monday.
Authorities said the 148-gt tug Crystal Coast (built 1983) made it through at 15:00 local time.
The bridge was destroyed last Tuesday when it was struck by the Dali.
The owner is Grace Ocean of Singapore, with management provided by Synergy Marine.
