More specifically, in any mission where you need to defend a friendly (Beaufort Station, the Dauntless, or the Fralthi), you should always concentrate on the torpedo-carrying craft. Against Barracudas you should launch a dumbfire and full guns to take them down quickly, and you should also try to take down the Red Mantas as quickly as you can. Don't worry about the Morays or the regular blue Mantas--they don't carry torps. However, DO also focus on any Stingrays that appear before they can combine and start using their big plasma cannon.