Somewhere in the oceans, a submarine is on patrol, in an exercise with other ships and aircraft. The crew has stood watch for days on end, without any contacts with the "enemy." Eventually, the sonarman notices something that may be the real thing. Once again, the crew goes to battle stations. Everyone is fully alert, looking, listening, waiting to make a move. Other times they have each been aroused to this state of alertness and preparedness, only to find that the object of their attention was too distant, or was one of their own kind, and thus not worthy of their full attention. Perhaps this time the stranger would be a genuine "target of opportunity."

Naval architects have told us that a submarine must be long and narrow. The older ones were eleven times as long as they were wide. The newer ones are broader, yet still long, slim, and even sleeker than ever.

Structural engineers have told us that a submarine must be cylindrical, with a rounded tip, and that the torpedo tube must also be cylindrical. Of course, the torpedo itself now must also be cylindrical, and long, like one of Freud's cigars.

As a little more information is uncovered about the newcomer, the word is passed informally among the crew. Everyone is now focused on one subject of interest. A methodical process begins, in which all the equipment, all the systems, and all the energy is directed toward a single goal. The information is analyzed, examined by other crewmen, carefully passed around among the most knowledgeable and best trained specialists on board. As the object of our attention gets closer, we can notice more things about it. Or her. The information begins to arrive a bit more quickly, but we still don't know enough to make our move. We watch and wait, angling for position, hoping to make the right interception of the target.

The analysis of the data begins to take on a rhythmic pattern, as we take a reading, plot the reading, compare the data point to the previous data, realizing that we are working in real time, save only for the delays caused by the speed of sound in sea water. We get into the groove. After the first few iterations, it all comes back to us. We pick up the skills, and we can pick a data point and plot it without even thinking about it. It takes on a life of its own. The rhythm drives itself on, without hesitation or diversion.

As we get closer, more and more information becomes available. Now, instead of grasping for any hints, we are overloaded with inputs. We have to pick and choose, deciding what we have the time and energy to deal with, and what we will ignore. Better data means that we want to plot more data points, and plot them faster. The intervals get shorter. The cycles of observe, plot, and analyze run faster. We forget that we might have been tired, or sleepy, or hungry, or angry, or whatever our previous mood might have been. We are intent on only one thing. The tension increases. We try to remain composed, for the sake of the exercise, but we forget about how we might look or sound or smell. Now, the process has taken us over completely.

When the stalking process has reached its peak of activity, with one last brisk cycle of observe, plot, and analyze, we eject a torpedo from the tip of the submarine. We have done our job. Now our "fish" must do the rest of the work.

This torpedo happens to be one of our acoustic homing models. It is sent out with its own energy, but with a certain amount of impetus from the tube from which it is ejected. It begins a methodical run at the target. It slowly pings, echo-ranging to find its way. In a while, it detects the target. It closes in. When the echoes from the target are strong enough, the torpedo shifts to high speed, to make sure that the target cannot get away. The pinging occurs faster and faster. Finally, the torpedo arrives at the target with a dramatic effect.

We begin to relax after a job well done. We start to notice that we are still tired, hungry, or sleepy, after all. We stand down from battle stations, and the energy level of the crew drops dramatically.

We decide to retire to the wardroom and have a cigar.