War Beneath the Waves by Don Keith Read Free Book Online Page A

and sinking. That meant leaving men topside if everyone did not get below quickly enough.
    There was little chance of recovering anyone if that happened.
    During World War II, submarines had a variety of jobs to do. They were asked to observe, look for enemy shipping, sink those ships, perform lifeguard duty, deliver men and equipment into hostile places, transport and deploy mines, and more. But primarily, they were designed and built to attack and destroy enemy ships. Thresher and her sisters were especially well equipped for that purpose.
    In addition to torpedoes, the submarines carried various weapons on their decks as well, including machine guns and small cannon. The captain usually had the opportunity to choose during construction what type of deck guns he wanted on his boat. Despite the assumption by many that subs did their damage only with torpedoes, many enemy vessels were damaged and destroyed using the boats’ deck guns as well. As it turned out, these weapons were used quite often in furious, close-range combat, especially by aggressive warriors like “Moke” Millican.
    There is often confusion about why these submarines are interchangeably called “diesel boats” and “electric boats.”
    While on the surface, four big diesel engines—very similar to those that drove diesel locomotives of that era—indirectly powered the vessel. Rather than actually turning the screws at the stern of the boat, the engines provided power directly to a generator and two electric motors that were, in turn, attached to twin screws that did the heavy work of propelling them through the water. Those big diesel engines also charged huge banks of storage batteries located in two separate compartments in the submarine’s belly.
    Those batteries were a key part of the propulsion system. They gave the boat electricity for the motors so she could run relatively quietly and without smoke when she was submerged. They also provided power for all the boat’s systems: lights, radios, radar, and the like.
    When the submarine was below the surface, the diesel engines were off. Motors, lights, sonar, instruments—everything electrical—got power from those batteries.
    That is why this type of submarine is often referred to as an “electric boat” in one breath and a “diesel boat” in the next.
    When the boats were at sea, diving was done daily in order to adjust the trim of the boat—its attitude in the water—as well as to determine the salinity of the water at different depths. A wartime dive could be completed in thirty to forty-five seconds if necessary.
    When a submarine starts to dive, it causes a shifting of the center of gravity and the center of buoyancy of the vessel. There is a point where the center of gravity of the boat coincides with the center of buoyancy, and the goal was to get past that point quickly. If a wave were to hit the boat from the side at that moment, the submarine could actually be flipped over.
    The diesels had to be stopped when the boat went into a dive. The intakes for air and the openings that released exhaust gases and smoke were closed. The speed was usually reduced to about three knots to save the precious battery power. Though these vessels could go as much as nine or ten knots while beneath the surface, they did it only for very short periods of time or in the case of an emergency.
    The amount of battery power available was one determinant of how long they could remain submerged. How much air was left for the crew to breathe was the other limiting factor. When off watch while submerged, crew members were encouraged to relax in order to cut their consumption of air. In battle, though, all hands were required to be alert and ready to go to work.
    When it came time to surface the submarine, the Klaxon would sound three short blasts to alert everyone on the boat about what was happening. High-pressure air was routed to the ballast tanks to blow water from them and outside into the surrounding