OTTAWA - Canada's glitch-prone, second-hand submarines will be with the navy until at least 2030, but defence planners will begin drawing up a replacement program within the next four years.

Vice-Admiral Paul Maddison, head of the Royal Canadian Navy, told a Senate committee Monday that losing the capability of underwater surveillance and attack would be a "dire day for Canada."

With the federal government in deficit-slashing mode, Ottawa has been awash in rumours about the future of submarine program and that the navy might be asked to give up one — or more — of the boats.

"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," Maddison said.

Since they were purchased from the British in the late 1990s, the four Victoria-class submarines have faced a series of costly and spectacular setbacks to the point where even Defence Minister Peter MacKay recently acknowledged they have "spotty" history.

The navy is currently conducting a submarine life-extension analysis to see what it would take to keep the current boats operating.

"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 in order to go through the various procurement and project planning, approval and funding gates to ensure there is no gap in submarine capability, which is what we faced in the 1990s."

Maddison's comments build on a public relations exercise last week that saw him and the country's top military commander, Gen. Walt Natynczyk, take a group of reporters aboard HMCS Victoria for an undersea diving exercise off Esquimalt, B.C. to demonstrate its capability.

The military has felt tremendous pressure since the CBC broadcast photos of a damaged HMCS Corner Brook, which smacked into the Pacific Ocean bottom last June. The images raised questions for the operational future of the boat, which Maddison says was never in question.

Yet, technical hurdles converting British systems, a fatal fire aboard one boat, and accidents have meant that the country currently has no combat-ready submarines, almost 15 years after they were purchased.

Maddison says HMCS Victoria will complete the test firing of its first torpedoes next week and be followed by HMCS Windsor in the fall — meaning by early next year there will be operational boats on two coasts.

HMCS Chicouitimi, which was ravaged by a 2004 fire on its maiden voyage to Canada, is expected to return to the fleet in 2013, he said.

In addition to being fixed, the Corner Brook has entered a refit which will keep the boat in the water for another 15 years.

The Chretien government bought the submarines from Britain in 1998 at a cost of $750 million, but since then National Defence has pumped over $1 billion into repairing and converting them to Canadian use.

To justify the purchase, former defence minister Art Eggleton said they would be updated with an air independent propulsion system to allow the boats to operate under Arctic ice — something that hasn't panned out.

Nuclear-powered submarines are considered the best for Arctic operations.

Maddison suggested, in considering replacements, the nuclear option would be off-the-table, but that planners would look at technology that's out there — mostly German and Swedish — that allows conventional subs to remain submerged for extended periods of time.

During his testimony, Maddison also revived the idea that the navy should possess an amphibious assault ship, a proposal christened by former chief of defence staff, retired general Rick Hillier, as the "Big Honkin' Ship."

Such a vessel would allow the navy, army and air force to quickly deliver humanitarian aid in future disasters.

Maddison says it's one of the lessons that came out of the 2010 earthquake relief mission to Haiti.

That operation saw the military use a rented supply ship to move vehicles to the Dominican Republic, where they had to be off-loaded and flown by C-130 Hercules into the disaster zone because the ports in Haiti had been destroyed.

With a landing ship, that could have been avoided.

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