Originally Posted by goldorak

It depends on the mod.
In RA for instance, ceiling and floor settings are used to delimit the search height for the torpedo. But once the torpedo acquires the target it becomes oblivious to the settings.



No, you have no way to find out the exact depth of your target. The only broad assumptions you can make pertains to the sub being on the same of the layer as you, or not and this works obviously if a layer is present.

If a layer is present and you want to be certain of acquiring the target, launch 2 torpedoes. One over and one under the layer.
In RA you can launch a single fish since its posssibile to instruct the torpedo to change depth (in the sense of letting the torpedo go over the other side of the layer).