The crane ended upside down in the water after the ground gave way during work on lock gates near Apperley Bridge.
An HSE investigation has now been launched following the incident last Friday.
Vince Moran, operations director at the Canal and River Trust, told the Telegraph & Argus: “First and foremost I am thankful that the driver or anyone nearby wasn’t injured.
“When planning and undertaking heritage repairs to any of our waterways we take steps to ensure that they meet stringent safety measures.
“Of course we need to understand why this particular patch of towpath gave way and will urgently review the circumstances behind this rare incident and apply any lessons learned from it.”