According to Google the maximum depth for a military sub is 5,000 feet, and most subs can't dive anywhere close to that. At 12,500 feet down I'd be surprised if the Norwegian equipment could do the job.I think I heard the Norwegians have equipment that can raise submarines.
I think the only hope is that their communication equipment has failed, but they're bobbing on the surface somewhere and the search planes will locate them.
If they're on the ocean floor I'm afraid they're done for