Newly released government records show that navy mechanics in Halifax had to scour the Internet and use eBay to find parts for one of its two supply ships.

But the briefing notes obtained by The Canadian Press, prepared for navy commander Vice-Admiral Mark Norman, show the technicians were fighting a losing battle to keep HMCS Preserver on duty.

The documents show many of the parts on the 45-year-old ship were "beyond acceptable limits" because corrosion issues had begun to compromise the vessel's structural integrity.

National Defence said last year that both Preserver and its sister ship HMCS Protecteur — gutted by a dangerous at-sea fire — would be retired before replacement ships arrived.

"It will be very difficult to continue to confidently operate her at sea until her planned divestment date in 18 months," said the May 9, 2014 briefing note, which was also copied to the head of military procurement.

The navy had planned to replace both ships, but the Conservative government pulled the plug in August 2008 because industry proposals were proving too costly. The new program is still up to eight years way from delivering new ships.

It's long been known that the ships were in precarious shape and getting worse, but the briefing said it "was no longer viable to expend limited resources" to keep them going.

The notes make evident the department's frustration that the ships were not retired on schedule. Technicians would fix one broken part and "once this is fixed, the next question is which equipment or system will be the next to fail."

Protecteur was recently decommissioned, while a formal ceremony for Preserver has to be announced.

Since the original manufacturers long ago stopped making spare parts, a "disproportionate amount of time" was being used to source replacements, "some of which have been procured via eBay," the documents found.

Defence gap at sea

A separate set of briefing notes, obtained by the federal Liberals, shows the impending retirement of the navy's Iroquois-class destroyers will leave an air defence gap for Canadian task forces at sea.

Liberal MP Marc Garneau, a former naval officer and astronaut, said the fleet is in a shambles, even with the multibillion-dollar upgrade to the Halifax-class frigates, which are the backbone of the navy.

Lauren Armstrong, a spokeswoman for Defence Minister Jason Kenney, said the navy will be able to carry out operations ordered by the government, both at home and abroad.

She added the Liberals are in no position to be lecturing on military procurement.

"As the minister said at committee, between 1992 and 2005, the previous Liberal government did not procure or even attempt to procure, with the exception of the failed maritime helicopter procurement, a single major piece of military equipment," said Armstrong in an email.

While the Liberals cut the defence budget deeply, under their watch the military did receive new LAV III armoured vehicles, M-777 artillery, CH-149 Cormorant helicopters, coastal defence vessels and the oft-maligned Victoria-class submarines.

Garneau said the absence of supply ships means Canadian warships will have to operate individually; they cannot form task forces of their own, and must rely on other nations for replenishment.

Armstrong responded by saying construction of the first replacement for the supply ships is expected to begin in 2017, and the government is also studying plans for an interim capability.

Without air defence destroyers, Canadian frigates will have to seek protection from long-range threats under the umbrella of U.S. combat vessels, said Garneau.

He said the Conservatives played politics with the navy by cancelling new supply ships on the eve of the 2008 election, and forced the military to accept Arctic patrol ships ahead of new destroyers.

"Mr. Harper decided he wanted to be known from a legacy point of view as big on the Arctic and has gone up every year for that photo-op," Garneau said.

"That's all driven by politics."