In a bid to keep Canada’s submarine program from sinking, the Royal Canadian Navy has brought one of its four prized ships to the surface for a rare glimpse inside.

CTV News Atlantic Bureau Chief Todd Battis was among a select group of journalists invited to spend a night under the waves aboard Canada’s lone east-coast submarine, HMCS Windsor. The underwater tour comes as the federal government conducts a review of Canada’s military, an audit that some fear could lead to cuts in the submarine program.

Visitors from the media were invited to spend a night on the submarine submerged off the coast of Nova Scotia and were assigned to bunks built inside torpedo holds.

HMCS Windsor is one of four diesel submarines purchased second-hand from Britain in 1998 for $750 million.

The ships have made headlines for several accidents and a litany of expensive repairs. In 2004, a fire aboard HMCS Chicoutimi killed Lt. Chris Saunders and injured eight others. In 2011, HMCS Corner Brook skidded across the ocean floor and sustained serious damages. By 2012, National Defence spent more than $1 billion repairing the ships and outfitting them for Canadian operational standards.

The Navy says the submarines are an essential tool for quietly detecting anything unusual travelling through Canadian waters. Russia is in the midst of expanding its own submarine program, and new attention is being paid to protecting Canada’s valuable Arctic waters and its resources.

“You can’t control a water space like a submarine can. You can’t use drones, you can’t use aircrafts … and a submarine goes out there quietly, effectively,” said HMCS Windsor executive officer Devin Matthews.

During the media tour, the Navy showed off new state-of-the-art sonar technology inside the subs, which the Navy has said brought HMCS Windsor “from 1980s technology into the 21st century.”

Rear-admiral John Newton says it’s important that the Navy stress why the submarines, which are scheduled to be retired by 2030, are a valuable part of the military.

“Between now and 2030 there’s a lot of space in there for us -- the Navy -- to articulate the benefit of this force to the government, and to the people of Canada,” said RADM Newton, who acts as commander of Canada’s Atlantic fleet.

For HMCS Windsor to hit the seas, she requires 48 crew members on board. The sub spent 200 days at sea in 2015 and is expected to do the same this year.

With files from CTV News Atlantic Bureau Chief Todd Battis