Using 46 motorized winches, the navy slowly lowered the HMCS Windsor into 35-feet of water as divers waited below the surface to monitor for damage or problems, The (Halifax) Chronicle-Herald reported.
The 2,400-ton diesel submarine was one of four Canada bought from Britain in 1998 for $750 million. All of them have been plagued with problems, including extensive rust and leaking.
The Windsor has operated at sea for only 332 days since arriving in Halifax in 2001 and has been in dry dock for refitting for the past five years, the Canadian Broadcasting Corp. said.
The three other submarines are all still being tested or refitted and Defense Minister Peter MacKay estimated it will be 2014 before all four are operational, the CBC said.