The vessel was on the Kennet & Avon Canal in Fobney Lock near Whitley, Berkshire, when it was suddenly swallowed up by the water.
The video shows how the narrowboat – owned by a woman and her husband – sank in seconds. What caused the rapid sinking is currently unclear.
The woman’s husband was said to be opening the lock at the time and was already safely off the vessel. However, it appears that she was still on board and without the timely intervention of a couple on the scene she may not have been able to escape.
The lock eventually reopened to river traffic six days later on Tuesday, August 16.
The Canal & River Trust said it would look to the boat’s insurers to cover the costs of the damage.
