[CrazyIvan]

1. The torpedo will be launched under the layer of 80% probability.
And 20% of that torpedo will be put above the layer.
If there is a MAD target detection, then the correct rotation angle is also set for the torpedo - at the start of the circular search, the torpedo will always turn toward the target.

2. Yes. Logical threshold for MK 48 is higher.

3. If the torpedo is close to the target - 800-1000 meters (for each torpedo different levels) - the thermolayer does not matter. (For heavy torpedoes (MK 48, UGST, etc) the distances are accordingly large - about 1300-1500 meters.)
However, the too much depth difference between the torpedo and the target will be affected here.
The target may simply not fall into the vertical cone of capture of the torpedo sensor.