out of my depth - how can I detect and evade enemies in SH4?

[Brett Sinclair]

Hi guys,
I switched over from SH5, and I was in for a surprise:
Destroyers are savage!
In SH5, I usually went down to more than 100 metres, rigged my U Boot for silent running and slowly edged away from the destroyers (taking a close look at the sonar cones on the map).
In SH4, I have the following problem: Having installed TFoTRS, I cannot see the visual or sonar ranges of enemy vessels on the map. Therefore, I cannot judge when to submerge, or dive deeper.
Furthermore, destroyers sometimes (after some modest time acceleration) appear right on top of me, even though my map is empty, bar a few distant sonar contacts.
What can I do?
Thanks.

Best,
Brett

p.s.:
It is very well possibly that I missed some obvious option, etc. Still trying to get used to the different menu and map structure.