How useful would someone who could always see what was happening underwater be as an ASW officer?
Short answerIt depends on range and depth: local vision may help little, while broad awareness could be more valuable in ASW or naval intelligence.
NotesPerfect underwater vision is not a self-explanatory advantage. Its value depends first on how far and how deep the person can see, because a view limited to the water immediately ahead may contribute little to anti-submarine warfare. Wider awareness could make the person useful as an ASW officer, but information at still greater scale might matter more in intelligence. The answer models a practical way to evaluate sensors: define their coverage and limitations before deciding what organization or tactic they enable.