The crew of HMCS Windsor is preparing for another attempt at a transatlantic crossing to Norway, after the submarine was forced to turn around last week because of a broken supercharger.

Wednesday afternoon navy personnel in Halifax were seen loading the submarine with supplies including food, drinks, paper towels and some of the crew's personal items.

The sub arrived in Halifax Monday morning, after canceling its first attempt to reach Norway, because of a major issue with a supercharger attached to one of its diesel generators.

They are similar to superchargers found in some cars and trucks, increasing the air density in an engine. This allows the engine to run more efficiently and generate more power.

A crew member drops rolls of paper towels down to a colleague inside HMCS Windsor. (Brett Ruskin/CBC)

Canadian Navy officials said last week it would take HMCS Windsor two weeks to cross the Atlantic Ocean and arrive in Norway for a NATO training exercise called Dynamic Mongoose.

The sub must now make that same trip in at least five fewer days, due to time lost coming back to Halifax.

The unplanned supercharger replacement is the second time in four months that HMCS Windsor has been forced to return to port for repairs.

Pressure to arrive on time

In February, a cell in one of the sub's batteries overheated and began smoking. A number of cells have now been disconnected from the batteries, but navy officials say the power system still passes its performance tests.

With this latest problem, the submarine was able to come back to Halifax using its second diesel generator. Crews began work immediately to assess the problem, install a new supercharger and ready the sub to head overseas.

There's pressure to get to Norway on time. International media outlets covering the NATO exercise have been told they'll have the opportunity to tour HMCS Windsor in Norway on June 20, along with a French and Norwegian frigate.

The exercise is designed to help NATO allies train for anti-submarine warfare.