I think what he might be getting at is - you push escape and you get the pop-up
that asks if you want to retreat. With a sub in range, that pop-up would not
appear. It's actually an interesting thought.

~ and by escort you mean the ship that was with them and not an actual escort.
You might want to change the wording as it was confusing at first.

why would you be trying to retreat from a game in the first place?...

I mean, if you loaded up a ship with the wrong FCS, or no ammo or something with
some legitimacy, that's one thing. but why in general would you be trying to retreat
for? to avoid being sunk?

secondly, a CV can't, to my knowledge, detect a sub. only FF, DD, CL and SS can
using a sonar sailor. unless you're using an npc escort ship equipped with a sonar
operator.

now, under regular circumstances, yes you need a sonar sailor. he has to be a high
enough level that you can actually find the sub to begin with, and be within range of
it, depending on the level of your sonar operator.

fyi, if you're red lining your engines to the max, you won't be able to use sonar at all
until you slow back down to normal top speed.

this is why I tend to shake my head in disgust as most of the DDs and CLs like to
charge Blitz style to their doom in gb2 games, instead of staying back to counter
subs then charge forth once holes open up in the enemy lines as BBs are sunk.

dude CV's can detect SS but since most if not all CV players don't wanna waste 1 slot to
use a sonar man idk if the got sunk by SS cos it is there fault

Sounds like a pretty bad bug...
An AA ship with long range and a fair amount of speed (Mr.Mandel?) could park and serve as a sub detection ship...