Hunting a submarine and defending a convoy place different demands on an ASW weapon. Ikara is preferred when a hunter-killer force is trying to locate and pursue a submarine. ASROC is preferred for rapidly firing torpedoes towards a threat and forcing it to keep its head down. In that defensive setting, suppressing the submarine's freedom to attack helps protect the ships being escorted. The preference therefore follows the tactical job assigned to the ASW ship.
Notable Point · 2:11:34-2:12:27
ASROC and Ikara serve different ASW priorities
The preference for ASROC is tied to protecting a task group, while Ikara is favoured for a more deliberate hunter-killer pursuit.