Thermal Layers??

[Ducimus]

Originally Posted by Sailor Steve

No, it didn't. SH2 did, but there is disagreement over whether the Germans even had the capacity to know when they passed a thermal layer.

Aside from that, to the best of my knowledge:
a.) A german uboat didn't have a Bathythermograph on board. (infact even SH4's representation of this is incorrect because Fleet boats didn't originally come with these onboard either. It was an invention that occurred later in the war. )
b.) Thermal layers were much deeper in the Atlantic, and not normally accessible.