OXYGEN GENERATOR See Bomb.
PARALLEL Electrical term, meaning connecting two bus AC load centers with a circuit breaker. The loads have to have the same frequency and be at the same point in the sine wave or else equipment can be damaged and fires can start.
PASSIVE SONAR Most common mode of employment of most submarine sonar systems. Sonar system is used only to listen, not to ping out active sonar beams, since pinging gives away a covert submarine’s presence. Use of passive sonar makes it difficult to determine a contact’s range, course, and speed (solution). TMA is the means of obtaining a solution when using passive sonar.
PATROL QUIET Ship systems lineup to ensure maximum quiet while allowing normal creature comforts such as cooking and movie watching. Maintenance on equipment is allowed, if it does not involve banging on the hull. Noisy operations are only permitted with the captain’s permission, such as reactor coolant discharge, steam generator blowdowns, etc.
PATTERN CHARLIE The point in space and time when a CINC’s airborne command post is a safe distance from its base, so that it is no longer vulnerable to nuclear destruction. The CINC can then take over from an operational commander in a bunker.
PCO WALTZ A melee situation where two submarines are aware of each other in a combat situation. fire-control situations using passive sonar become impossible to ascertain due to constant maneuvers of the target. Both combatants tend to switch to active sonar and get weapons in the water. If the ships are too close, weapon targeting becomes nearly impossible and collisions become highly likely. In some situations, commanding officers may elect to clear datum until the battle can be controlled. Term originates from Prospective Commanding Officer School at Groton, Conn., where many subvs-sub exercises are done.
PD (PERISCOPE DEPTH) An operation when the ship comes shallow enough to see with the periscope. Certain operations can only be done at periscope depth by decree of the Submarine Standard Operating Procedures manual. Such items include steam generator blowdown, shooting trash from the TDU, and blowing sanitary. Some things can only be done at PD, including radio reception of satellite broadcasts, reception of a NAVSAT pass, and ESM activities. Slows the ship down since high speeds can rip off the periscope. Dangerous operation since quiet surface ships can get close without being detected by sonar. See Emergency Deep.
PHOTOINT Photographic intelligence, such as the interpretation of satellite photos.
PILOT A person who has detailed knowledge and experience of a port and approach waterways. Taken on prior to entering or exiting port to serve as an advisor to the captain.
PLAIN (POINT OF INTENDED MOTION) The center of the box. The moving point in the ocean that a transiting submarine stays within a predefined range of at all times. See Box.
PING An active sonar pulse.
PIRANHA CLASS The SSN-637 class of submarines, headed by the lead ship of the class, the USS Piranha. Press release from the program at the launch of the USS Piranha reads: “Piranha is a streamlined, highly advanced, and maneuverable antisubmarine warfare platform which uses the most advanced technology to accomplish her mission… Super quiet, deep diving, and swift. Piranha is one of the most capable warships of the United States Fleet.”
PLEBE A first year man at the U.S. Naval Academy at Annapolis.
PLOT TABLE A glass topped boxlike table that has a mechanism that moves in scale to the ship’s motion in the sea. Table accepts input from the ship’s gyro and speed indicator to do this. When tracing paper or charts are taped to the table top, the ship’s motion can be plotted and recorded against time. Used for the geographic manual plot to determine contact solution. Also used to map polynyas. Ancient low-tech method of doing all these things, it has the advantage of not relying on computers, and is thus “bulletproof.”
POLYMER A chemical formed of long chainlike molecules.
POLYMER INJECTION The injection of a polymer into the boundary layer of a submarine at the nosecone. The slippery liquid reduces the skin friction of the ship, reducing the drag. The result is the ability to dramatically increase ship’s top speed for short periods of time. Ideal for torpedo evasion.
POLYNYA Thin spot in the polar icecap where a submarine can surface by breaking through the ice.
POOPY SUIT Underway uniform worn by American submariners. Usually cotton coveralls. Origin unknown.
PORK CHOP Nickname of the Supply Officer.
POSITION ONE (POS ONE) Furthest forward console of the Mark I fire-control system. Usually set up with the captain’s and XO’s guess solution to the contact or displays the geographic display for a God’s-eye view of the sea.
POSITION THREE (POS THREE) Furthest aft console of the Mark I fire-control system. Usually set up to program torpedo tubes and weapons.
POSITION TWO (POS TWO) Mark I fire-control console between Pos One and the Firing Panel. Usually set up on the Line-of-Sight mode so that the Pos Two officer can come up with his own independent fire-control solution under the XO’s supervision.
POSITIVE DISPLACEMENT PUMP A pump that uses pistons, diaphragms, or moving rotors to force liquid from a low pressure area to a high pressure area.
POWER RANGE Nuclear power level above the intermediate range. In the power range, steam can be produced by the reactor for propulsion.
PRECIPITATOR A device that removes particles and oil droplets from the air by passing the air over a highly charged set of plates or wires.
PRESSURE HULL Hardened steel section of a submarine able to take sea pressure at depth. The “people tank.”
PRESSURIZED WATER REACTOR A PWR produces power using water at high temperature and pressure as both a moderator and coolant. Also uses a primary water coolant loop that keeps the radioactivity confined. A secondary system, the steam system, takes energy from the primary coolant and uses it for propulsion — the secondary system is not radioactive. As opposed to a BWR, boiling water reactor, that acts as a reactor and boiler, in which the reactor’s coolant is used in the turbines, making the drive train’s internals radioactive.
PRESSURIZER Tank in the primary coolant system that keeps the water in liquid form even up to 500 degrees by using heaters and raising the water in the pressurizer to even higher temperatures and pressures.
PRESSURIZER LEVEL The level of the pressurizer tank is the main indication of the amount of primary coolant in the primary coolant system. Large changes in core temperature can raise or lower the level due to thermal expansion or contraction of the water. A loss-of-coolant accident is detected by a falling pressurizer level.
PREUNDERWAY CHECKLIST Set of checklists used to get a submarine under way, including valve lineups and switch position checks. Considered of equal complexity and scope to a Space Shuttle countdown checklist.
PRIMARY COOLANT SYSTEM The piping system that circulates primary coolant from the reactor core to the steam generators (boilers) using reactor main coolant pumps. As opposed to the “secondary” coolant, the steam going from the boilers to the turbines for propulsion.
PRIORITY A level of urgency of a radio message below IMMEDIATE and above ROUTINE. Reception guaranteed on the same day.
PROMPT CRITICAL Under some conditions, uranium can be critical on fast neutrons instead of thermal neutrons. One example is a bomb undergoing a nuclear explosion. A second is a core in a reactivity accident such as a control rod jump, where the core becomes prompt critical, critical on the fast neutrons that are emitted “promptly” by the fission reaction. A core that is prompt critical is milliseconds from either a steam explosion or a prompt critical rapid disassembly.