All four of Canada’s submarines were tied up last year for repairs and maintenance — news that has the opposition Conservatives questioning whether the Liberal government can keep the second-hand fleet afloat for another two decades.

In response to a written question before Parliament, the Department of National Defence said the boats “spent zero days at sea” in 2019, but three of the four would return to service at some point this year.

Over the year, HMCS Victoria, HMCS Windsor, HMCS Chicoutimi and HMCS Corner Brook were in various stages of repair and maintenance. They also went into drydock for long-term upgrades meant to ensure the submarines remain operational until the end of the next decade.