[Shadriss]

In the era that we're talking about (the 80s) the US had a significant acoustic advantage over the Soviets (until John Walker happened... scumbag). The VICTORS/DELTAS were noisy platforms, and US boats would routinely track them from well beyond 20 Kyds on passives alone.

The Russians always suspected it, and John Walker confirmed it for them. The average Soviet skipper assumed that, if he made contact with a US boat, he had already been tracked for several hours or even days.

With that kind of disadvantage, there is no way a Soviet boat would go active as much as these boats do in the game. The surface pukes? Sure. But not the subs. They had enough disadvantages to work with that going active and making it even harder to stay undetected (the true goal of any submarine) would have been a non-starter.

In game terms, however, it makes sure you don't steer in a random direction and never make contact.