There is a reference in the book (Hard to find 1 sentence in 400 pages) where it mentions the Captain hanging by the scope to nail an unescorted freighter.
But yes I'm aware of all the above, and the consequences.
I know NYGM models slow sinking (not sure about GWX ) to try simulate this, and the expense of battery power.
What I really interested in is when a calm sea prevails in SH3, to 'hang' in one position with no power for hours, listening on the hydrophone which should have a range beyond the horizon in such conditions, coming up when more oxygen is needed. Maybe this can be modded, with a basic minimal power drain on the batteries. This in effect would be a perfect ASW avoidance trick while waiting for something to appear - and even better for anti-ASW in perfect conditions.
Would be cool
