Naval planners have started to lay the groundwork for the possible replacement of the country's second-hand, glitch-prone Victoria-class submarines, arguing such warships are a necessary part of Canada's arsenal.
Planners say the country will likely need bigger, quieter boats that can perform stealth missions, launch undersea robots and fire guided missiles at shore targets.
A nine-page briefing note for the country's top military commander last year sets out the justification for keeping a submarine capability, and comes at a time when the Harper government wants budget savings in both the nearand long-term.
The report looks at what kinds of boats will be on the market between 2020 and 2050.
Ottawa was awash in rumours last spring that the submarine program was on the chopping block because of its enormous expense and repeated setbacks, including a fatal fire aboard one boat in 2004.
"Submarines are the ultimate stealth platform, able to operate in areas where sea and air control is not assured, and to gain access to areas denied to other forces," said a 2011 briefing for Chief of Defence Staff Walt Natynczyk.
"A capable submarine force creates uncertainty; countering them is difficult, expensive and cannot be guaranteed."
Investing in submarines is prudent because "in the event of global tensions these relatively cheap assets will counter projection of power and hinder freedom of movement and action."
According to defence experts, that was a veiled reference to Arctic sovereignty, which the Harper government has made key policy platform.
Dan Middlemiss, who has written extensively on naval strategy, said the government clearly sent a message to the navy last year about the current, troubled fleet, warning: "Get these boats in the water or else."
That the program has been in jeopardy was subtly underscored by the navy's top commander, Vice-Admiral Paul Maddison, during an appearance before a Senate committee earlier this year.
"Assuming that Canadians will continue to see a submarine capability as a critical capability for our Canadian Forces," he said, "I would envision initiating a next-generation submarine discussion within the next three or four years ... to ensure there is no gap in submarine capability, which is what we faced in the 1990s."
Under questioning, he was more pointed: "In terms of surveillance of our ocean approaches and the protection of our own sovereignty, I would consider a submarine capability critical.
"And so to lose that for a G8 nation, a NATO country like Canada, a country that continues to lead internationally, and aspires to lead more, I would consider that a critical loss."
