A total of 31 people had to be rescued or swim to the dockside when an amphibious tourist bus sank in Liverpool’s Albert Dock on Saturday.
A number of people were taken to hospital after the Yellow Duckmarine vessel went under.
A rescue operation – involving police, ambulance, coastguard and the RAF – was mounted and 31 people were helped out of the water.
Of those, 18 people were taken to the Royal Liverpool Hospital for treatment, mostly for shock, but all were well enough to be discharged.
A “multi-agency investigation” has been launched into the sinking – the second in three months.
A spokesman for Yellow Duckmarine told the Daily Telegraph that the company was working closely with the Maritime & Coastguard Agency, and Merseyside Police.
An Albert Dock spokesman said: “Following the incident, Albert Dock directors would like to praise the response of the emergency services and its onsite security team and will co-operate fully with any investigation.
“Our team followed their emergency response procedure, ensuring the safe disembarkation of passengers on board.”