Many moons ago when the Vietnam police action was

Many moons ago when the Vietnam police action was occurring. GMT 3 nuclear weapons specialist. Anti Sub warfare division.   Also got to hobnob with torpedomen, and sonar techs. Got to sit on the sonar stack and search for underwater contacts.  Never forget the nite I saw something interesting and focused the sonar beam directly on the contact for better resolution.  Within about 60 seconds, the officer of the watch from combat central walked into my little space and told me that was not a contact and to cease tracking immediately. Always wondered what kind of a whale I found that nite and who got nervous. Just like here.  What kind of a whale are we tracking? It's been underwater a long time, off the sonar(radar), know it's gotta surface soon.  Thanks for your service as well.  My very best to you,  Jim