Canada's fleet of used submarines is out of commission.

All four subs are now sidelined because of over-budget and delayed refits, damage from running aground, or in the case of HMCS Chicoutimi, a fire that gutted the sub's interior.

The benching of all of the navy's subs marks the first time since the mid-1960s that Canada's Maritime forces are without a working submarine.

MP Peter Stoffer said the deal to buy four used British subs has been a disaster and leaves a hole in Canada's security.

"When somebody kicked the tires on these subs, they missed a lot," said Stoffer. "If the bad guy knows we don't have any submarines in our waters, then polluting, drug smuggling, illegal immigrants, overfishing, all these things can happen if we don't have a so-called silent deterrent out there."

Since the first Victoria class sub arrived in 2000, the program has been plagued with problems. Dents in the hull, cracked valves and a deadly fire have haunted the fleet and now once again questions about the crippled subs have surfaced in parliament.

On Friday, Defence Minister Peter MacKay defended the submarines in the House of Commons.

"No one would deny there have been challenges with respect to these submarines, which were purchased by the previous government. In fact, Mr. Speaker, submarines bring an important credibility and important capablity to the Royal Canadian Navy," said MacKay.

The government bought the British submarines on the navy's recommendation. The navy is defending the billion dollar plus submarine program saying the boats are vital to the defence of Canada even though none at the moment are capable of firing torpedoes, submerging or even venturing out to sea.