Unrealistic or cheat..?

[cyrusthevirus]

I played the Kilo demo mission today. Everything seems to be fine.

I classified most of the contacts, and since I classified the hostile contact I was looking for ( Cargo ship) visually, I waited a while
in order to place myself in the "right position" to strike and hide.
After I shot 2 torpedos( and units where running normally) I was waiting to see them hit the target. And there it was: Shortly, before the torpedo
impact, the Target itself accelerate its speed, and the torpedo wouldn`t hit.

Is this an unrealistic behavior or even a cheat?

Or could a target like( a cargo ship) be able to either accelerate it speed to such an extend that a torpedo was unable to catch it /and can a cargo ship detect a torpedo...?

Or do I have to use a different tactic to engage such a target?

Thanks for answers,

Cyrus