I would suggest that because of the limited time a convetional submarine can remain dived they would only be used for coastal operations and not for under ice work.

Working under an ice cap is extremely dangerous in any submarine. In order to surface in an emergancy an area of thin ice needs to be found, a polnya.

Further it often takes several days to get into position under the ice. Submarines that do go under the ice go in quite long distances.

The SSK (conventional boats) would need to snort diesal every 4 days, and SSN can remain dived for weeks.

However an SSK is very quiet and can operate very effectivley against other submarines in its hunter killer role or to be used for tracking surface units of a 'hostile' nation without them being aware they are under observation.

Submarines are rarely used for flag waving, however back in the 60's when the Argentinians were contemplating an earlier invasion of the Falklands the first of the RN nuclear powered boats, HMS Dreadnought was sent down there and when it was in position it surfaced and allowed its presence to be known, the Argentinians backed off.

The Swedish company Kockums which designed the Collins class boats for the Aussie Navy have an option that allows an extra section containing a Stirling engine to be fitted into the boats. These are a type of closed cycle engine that can operate of fuel and air when dived and allow the boat to be propelled in a combination of both main battery propulsion and engine propulsion. They are very quiet too.

I do not understand why the Canadian Navy ended up with 18 year old boats when there are better option available.