Hi w
This time piece U-Jagd is the back of the stopwatch in SH5.
Post #108 U-Jagd Tutorial For Silent Hunter 5
This might be the sort of thing you are referring to?
SH4 IIRC does not show ship lengths in the recognition manual.
You can still use the 3 minute measurement to get the targets speed either by using map contacts or taking bearings from the periscope.
I often use a kitchen timer for both metric and imperial times.
Peter