Very small brand-new submarine...only 30 people onboard.
"Gotland was selected to be the OPFOR because of its unique propulsion system. Gotland is the first submarine in the world to operate with an air-independent propulsion (AIP) system."
What it is is a modified diesel propulsion system which allows them to stay submerged and run on diesel for a couple weeks without snorkelling for air (as opposed to most diesels which have a requirement to run on batteries while submerged below snorkelling depth). While running on batteries, diesels are the most quiet submarine around. (The US has several that do not officially exist.) The big problem is that while this is a good boat for coastal defense, it will only run at 5 knots if it expects to stay submerged for two weeks. This makes it no threat to a carrier task-force in the middle of the ocean, which typically runs at 25-30 knots (in peacetime, anyway). This little boat would never catch them on the surface, or submerged. It would have to know where they were going to be ahead of time, and lay in wait. As I said, an excellent coastal defense boat...but not good for much else...unless you want to use it to test your detection abilities.
It's tough to find something when it can't catch you to begin with...kind of like looking for a needle in a haystack. But most likely they'll get a little cocky, and one of the US attack subs will find it.
Melody and Instruments for the soul...