What you have been discussing is a Sub supporting a surface group.
The US tactic was to use 3 boats, one ahead maybe up to 300 miles. This was based on the main threat being from the Oscar SSGN and it's SS-N-19 Shipwreck SSMs, range around 300 miles. Two subs were located on the flanks usually 30-40 miles out to handle SSNs trying to sneak in and a very brave Oscar skipper.
Now with cutbacks I am sure it has been changed. The boat out front was far enough out that the SAG did not present a problem, noise wise.
The SAG itself was to handle the close in ASW protection.
There was times during the cold war that we had the resources to actually use this, but in all honestly, most of the time DS was one boat way out ahead, and we sues sprint and drift. Apparently, according to what I read in this post it is being questioned. It works and we always thought, or at least we did it was the most effective way to use a sub. We even used during transients.
Ron Banks MMCM(SS), USN(Ret)
