From what I remember of my time in the Navy you're correct ships don't go completely dark on the electronic spectrum during time of peace. However that said I can envision times during war where a ship would go dark on the spectrum including IFF and strictly use passive sensors to feel their way around. Certainly submarines even during peacetime use strictly passive sensors because they want to stay hidden even during the peace time.<br/>
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Peter L. Berghold &lt;<a target="_top" href="mailto:xxxxxx@berghold.net">xxxxxx@berghold.net</a>&gt;<br/>
Brewer, Gourmet Cook, Dog Sport Enthusiast, Navy Veteran