HMCS Windsor, which completed a $209-million refit just 18 months ago, will be hauled from the water in March, the navy has confirmed to CBC News.
A navy spokesperson said one of HMCS Windsor's two diesel engines will be removed and replaced during the unscheduled docking.
A naval source told CBC News the job will take at least seven months but could last longer, depending on how the massive 16-cylinder diesel engine is stripped from the submarine.
The broken Paxman Valenta engine weighs eight tonnes and was commonly used to drive British trains.
Canada's used British-built submarines are fitted with a special hatch that may allow the navy to simply pull the engine from the 20-year-old HMCS Windsor. But if the hatch — called a Dutch breach — turns out to be too small, the navy will be forced to cut the submarine in half to remove the engine.
It is likely the 2,400-tonne Windsor will be hauled from the water at the navy's dockyard in Halifax and stored in a newly constructed $20-million submarine shed that will shelter the sub from the elements.
HMCS Windsor should have been operational until 2018 after a five-year refit which began in 2007. The refit was to take two years and cost $45 million. But in April, Capt. Luc Cassivi, director of Canada's submarine force, told CBC News the final tally was $209 million.
Shortly after the navy slipped the Windsor back into Halifax harbour in the spring of 2012, the diesel engine was declared unusable. The diesel engine is used to charge the batteries the submarine depends on to drive electric propulsion motors when submerged.
The engine failure meant that even after hundreds of millions spent on upgrades, the Windsor only had one working engine, which restricted the sub's ability to dive and manoeuvre.
The submarine's 48 crew members were forbidden to take the submarine from home waters because of the useless engine.
Short on answers
Although the navy has confirmed HMCS Windsor will be on land for an expensive and complicated engine removal, it has not answered many questions CBC News has asked concerning the work.
CBC has submitted the following questions to the Department of National Defence:- The projected costs, timelines and general schedule of the work to be done to the Windsor.
- Will a submarine be transferred to Halifax to replace the only sub on this coast?
- Is the navy confident that the engine can be removed through the Dutch breach?
- Is the navy considering cutting the sub in half?
- Will the generator/engine be replaced by the exact same Paxman model or will it be another type?
- Where is the replacement engine right now?
- Must the replacement be imported from the U.K.?
- How much will the replacement engine cost?
The Department of National Defence has not provided CBC with answers to any of these questions. CBC News has asked to speak with a navy expert who could provide background information on HMCS Windsor, but that request has not been acknowledged.