ROCN SS-791 海獅 "Hai Shih" (Sea Lion) was originally built in 1944 (yes, it's a WW2 boat) as the US Navy Tench-class diesel-electric submarine USS Cutlass. It is now year 197x (in game, is 200x). Now equipped with the GUPPY II upgrade and new Italian 533mm wire-guided torpedoes, is the 791 good enough to go up against a Type 091, aka "Han" class nuclear submarine of the People Liberation Army Navy?
In a previous encounter, the Han didn't even have a chance to fire back, before it ate the two torpedoes, thanks to a very convenient thermal layer.
But what if there is no thermal layer?
------ SPOILERS AHEAD ------
Unfortunately, the story gets really boring. The moment the Chicom sub detected something anomalous, it turned tail and went flank speed of 25 knots, which is enough to outrun any torpedo the Tench/GUPPY had. The Italian torpedo has a top speed of 36 knots and only 10 minutes duration at that speed. NOT enough. Han even fired 2 torpedoes back, but didn't have the range to come close to the Tench/GUPPY. The Tench/GUPPY captain calmly ordered ultra-quiet at 15 ft, and just waited for the torpedo to go dumb. However, he can't get a hit either, as the Chicom sub was using active sonar, and without a thermal layer, he can't get close enough. After expending 8 torpedoes with zero hits in 3 attacks, all of which were dodged by the Han, the Tench/GUPPY decided to go home and sulk. Han's crew needed several changes of underwear.
In other words, I was lucky last time. I am good, better than the PLAN AI, but not THAT good.
Which *does* bring up an interesting question: just how many decoys does the AI Han carry?