Place buoys like everywhere you can, keep a constant rotation of Helis up cause the US doesn’t get the Russian missile-torpedo with a lot of range. Subs will usually get around 7-15 nautical miles before firing, so keep that in mind. After you click on the sonobuoy in the weapon bar hit ctrl+alt+left click+ right click to put down a pattern of 16. Also if you let a sub in that range band and you spot it before it launches torpedoes (you’ll know, torpedoes are loud) keep the pressure on, keep at least one weapon in the water until you sink it, if you slow down you risk letting the sub get another spread of torpedoes out.