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A Fine Mess You Got Us Into This Time, Albert
by Jean d'Isle

ast week, as you may recall, my team of specialists and I embarked aboard a nuclear powered submarine and set sail on a classified mission. (Click here to read last week's article.) Broad guidance for execution of the mission was to transit to the operating area, execute the mission, and return undetected by either friendly or hostile forces.

The modern attack nuclear submarine is particularly well suited for such a task. It has an exceptionally sensitive sonar system which allows it to detect, and usually classify, noises in the water at great distances. This capability, coupled with highly sensitive electronic systems which alert it to radar signals, allows the submarine to avoid, or investigate, targets long before the submarine comes within range to be detected by the target.

The transit to station was routine, with periodic excursions to periscope depth for radio traffic or to investigate contacts. The approach to the mission area was conducted at a speed and depth to maintain the mission's covert status. The long transit time offered an opportunity for the ship's crew to conduct training and emergency drills. My team also used this time to check and recheck equipment and to review details of the upcoming operation.

Once in the operating area, all contacts were considered hostile and evasive tactics were used. However, as contacts became more numerous, evasion often consisted of remaining quiet and deep while hostile units passed over us.

One evening, as we were attempting to maneuver our way clear of a concentration of hostile surface contacts, we found ourselves boxed in, with no clear course to steer to vacate the area. Using the "quiet and deep" tactic appropriate in such situations, we anticipated our slow speed would gradually carry us beyond the problem area or that the surface ships would eventually move on. The great thing about nuke submarines, I remember thinking, is that they can stay down forever.

That's when the lights went out.

When a ship loses its electrical load, battery powered battle lanterns automatically click on in all the compartments and the ship's intercom shifts to battery backup. In the dim light of a solitary lantern, I could barely make out the rest of my team as we all froze in place, waiting for some indication of the seriousness of the problem. The unmistakable voice of the Commanding Officer erupted over the intercom, "Will someone tell me what the hell's going on?"

The chilling response from the engine room: "Captain, we've just had a reactor scram." This announcement was accompanied by a wailing siren in the background -- a sound whose memory gives me visceral twinges 30 years later.

A reactor scram is, simply put, the automatic shutdown of the nuclear reactor and complete loss of primary power to the submarine. (I don't know if "scram" is an acronym; but if it is, it probably stands for "Stop Chain Reaction, Avoid Meltdown!") A brief layman's explanation of this process might be useful. A nuclear reactor is a furnace, fueled by radioactive material. The heat from the reactor turns water into steam, which makes the screws turn and the electricity flow. The intensity of the reactor's output is controlled by graphite rods whose retraction from the reactor core allows more nuclear reactions and more heat, and whose lowering into the reactor has the opposite effect. A scram occurs when sensors recognize a problem in the system that is so severe, the rods are automatically dropped into the core, shutting down the reactor.

When the cause of the scram has been identified and corrected, the reactor is brought back on line by slowly withdrawing the rods. If circumstances dictate (e.g., consequences of lost propulsion may be worse than the risk of bringing the reactor on line without first isolating the cause of the scram), a fast scram recovery can be initiated.

As forward momentum is lost, depth control is lost. Like an airplane, a sub must have lift across its control surfaces to control its rise or fall. Without depth control, a sub either pops to the surface (broaches) or sinks.

Getting back to our story, while broaching might seem a preferable alternative to sinking, our situation made that less attractive. To broach in the midst of hostile units, without power or propulsion, would not be a fun thing. Had we not been ballasted heavy, we would have broached no matter how opposed we were to that option. Instead, we slowly sank, stern down, at about a 15 degree angle.

Meanwhile, fast scram recovery procedures and attempts to start the Electrical Propulsion Motor (EPM) were initiated. Unfortunately, the EPM, an emergency backup motor, refused to start. And we continued to sink. As the boat went down, down, down, the tension level in the boat went up, up, up.

Fast scram recovery was successful; but before we could muster a collective sigh of relief as the reactor was brought back on line, the wailing of sirens again pierced the the dim interior of the boat...a second reactor scram. And we continued to sink. I recall thinking at the time that Einstein's calculations must somehow be flawed and we were going to be the unfortunate guys to prove it. ("Look at this equation again…Albert forgot to carry the 1..."). The consequences of an uncontrolled descent can be disastrous -- USS Thresher and USS Scorpion were both lost in peacetime accidents when loss of depth control plunged them to crush depth.

Our situation was serious, but by bubbling air into the ballast tanks we were able to slow our descent considerably and not alert the enemy above. Through this technique, we finally reached a depth equilibrium and hung suspended well above the danger point. The surface units gave no indication that they were aware of our presence and gradually moved their center of activity away from us. After an eternity, the engine room announced (unaccompanied by sirens) that the reactor was back on line. But stomachs and jaws didn't unclench until lighting was restored and we began our withdrawal from the area.

We went on to complete our mission successfully and had an uneventful return to port.

I came away with my confidence in nuclear power shaken, but with a renewed respect for the skilled submariners who willingly drop through that deck hatch day after day and year after year and go in harms way.

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Jean d'Isle is a retired naval officer living in Hawaii. During his military career he served in a number of overseas assignments, including Germany, England, Spain, Viet Nam and Puerto Rico. Following his retirement, he was an adjunct faculty member of Hawaii Pacific University and is currently under contract with the U.S. Navy at the submarine base in Pearl Harbor.

Jean's column, View From d'Isle, is a regular feature of VegSource On-Line Magazine.