From: Melbourne, Australia
So much of this involves understanding the precise limitations of one’s own weapons platform, in this case a diesel sub with torpedoes that are not capable of outrunning the target frigate. The scenario vexed me, too. I did not realise at first that a submarine’s passive sonar can maintain contact with a target using active HF sonar from about 350 ft below the surface. So, even though the object of the exercise is to use shallow waters tactically, I could not reach really shallow water in time to intercept the frigate so I settled for medium depth, picked a spot and stopped moving, as advised by the briefing. You need a solid contact (passive, from the ship’s HF active sonar) and a lot of patience to allow it to get really close and to determine its direction of travel in order to maneuver slowly into its baffles. To ensure a high torpedo PK, you have to be *really* close because the target ship is fast. If it were cruising at 20 kts when first detected, I don’t think this diesel boat could ever get a decent torpedo shot at it but perhaps I am mistaken. Luckily it’s meandering along at about 12 kts.
The only misleading thing to me about this excellent tutorial is the lack of a definition of “shallow”. As I said, I could only stage the intercept in medium-depth water but 350 ft was deep enough not to get detected while stationary (a noisier nuclear sub would have been detected, I imagine, even while not moving) yet not too deep to launch torpedoes. The slightly tricky thing is to pick up the contact again after going too deep to maintain visual contact via periscope and/or HUMINT.
Good point, I'll add a better definition of shallow in the next update.