A term left over from the 1940s when primitive lab reactors had a single control rod suspended by a rope. An emergency shutdown would be done by cutting the rope and letting the rod drop by gravity. The safety man was called the Safety Control Rod Ax Man — hence SCRAM.
SCRAM BREAKER A circuit breaker that interrupts power to the latching electromagnets of the control rod drive mechanisms. When the breaker opens, electrical power to the electromagnets is shut off, the magnets lose their magnetism, and the latches of the rods open, allowing springs to drop the rods to the bottom of the core.
SCRAM SETPOINTS The power level that will result in the protective circuits scramming the reactor. There are also setpoints for amount of flow through the core and core pressure.
SCRAMBLED EGGS The gold branches of leaves sewn onto the brim of a senior officer’s cap.
SCRUBBER C02 scrubber. Atmospheric control equipment that rids the ship of carbon dioxide (from breathing, the diesel, and the CO burner) by blowing it over an amine bed.
SEA TRIALS Post construction shakedown cruise of a ship. Done to ensure the equipment lives up to the specifications and that the ship is ready to perform its mission.
SEARCH CONE A cone of ocean extending forward from the nosecone transducer of a torpedo. Anything inside the cone can be detected and homed on.
SEAWOLF CLASS Newest class of American fast attack submarines, the successor to the Los Angeles class.
SECTION TRACKING TEAM A fire-control team stationed to man the plots and fire-control system when tracking a hostile contact for extended periods of time. Modified battle stations. So named because each watchsection (similar to a shift) has its own tracking team.
SECURE PULSE FATHOMETER A fathometer (bottom sounder or bottom contour sonar) that bounces a downward focused secure pulse off the ocean bottom to determine depth below the keel. Pulse is secure because it is short duration and high frequency. High frequencies are quickly attenuated by the ocean.
SELF-OXYDIZING FUEL Fuel such as hydrogen peroxide that contains its own oxygen. Needs only a spark to react and explode violently. Capable of burning underwater. This fuel is frequently used in torpedoes. Its use makes a fire in the torpedo room that much more hazardous.
SELF-SUSTAINING (1) When a jet engine’s turbine has enough power produced to turn the compressor shaft and sustain engine operation. (2) When a nuclear reactor’s steam plant is producing enough electrical power to power its own reactor coolant pumps and electrical circuitry (taking about 10 % power). The ship can then divorce from shorepower.
SES (SONAR EQUIPMENT SPACE) A room in the operations compartment taken up by large electrical cabinets containing power and signal circuits used by the BAT-EARS sonar suite.
SEWER PIPER Another derogatory term for submariner, used by aviators and surface sailors.
SHAFT SEALS The mechanism used to allow the screw’s shaft to penetrate the aft bulkhead of the engineroom without seawater leaking in. Furthest aft point inside the ship.
SHAPED CHARGE An explosive charge that is designed to focus the energy of explosion in a particular direction. Used to break through tank armor and double submarine hulls.
SHARKTOOTH SONAR Slang name for the AN/BQS-8 underice sonar. The transducers are in the forward edge of the sail. Sonar is active, transmitting a high frequency police siren sound, able to transmit and receive simultaneously to chart ice obstacles ahead of a submarine under ice. Also includes a network of topsounders on the sail and hull to look up to find distance to overhead ice and ice thickness. Named SHARKTOOTH because the emitted frequency, when plotted against time, resembles a series of ramps, like shark teeth.
SHIP CONTROL OFFICER Russian equivalent to a helmsman, except the watchstander is an officer directing a highly automated distributed control system that controls the motion of the ship. Reports to the Deck Officer.
SHIP CONTROL PANEL (SCP) The console from which the ship’s depth, course, and speed are controlled. On American submarines, this console resembles a 747 cockpit, with the Sternplanesman on one side, the Helmsman on the other, and the Diving Officer behind and between them. On Russian submarines, the console is the control station for the automated distributed control system that directs the motion of the ship.
SHIP CONTROL TEAM The watchstanders manning the Ship Control Panel, including the Sternplanesman, the Helmsman, and the Diving Officer. Sometimes includes the Chief of the Watch, off to the port side at the Ballast Control Panel.
SHIPS INERTIAL NAVIGATION SYSTEM (SINS) A multimillion-dollar complex navigation system using a sophisticated gyroscope and support electronics to estimate the ship’s position accurately at any time.
SHOCK WAVE An instantaneous change in fluid properties (a disturbance) that travels outward at the speed of sound in the fluid (sonic velocity). Examples include a sonic boom and the shock wave from a nuclear blast.
SHOOT ON GENERATED BEARING Captain’s order to shoot a torpedo based on the fire-control solution’s estimate of where a target should be, not on the last actual bearing from sonar (See Match Bearings and Shoot). Generally considered best way to shoot with the Mark I fire-control system. When ordered, the fire-control team locks in the fire-control solution to the target, and when the torpedo reports back, the captain is given one last chance to say either “Shoot” or “Check fire.”
SIDESCAN SONAR Sonar used to examine objects on the ocean bottom. Used to find the Titanic and wreck of the USS Stingray.
SIGINT Signal intelligence. After intercepting an enemy radar, the emitting platform can be identified.
SIGNAL EJECTOR A small torpedo tube used to eject Hares (for signalling surface ships), communication buoys (which can transmit hours after the ship has cleared datum; also used for SUBSUNK buoys), and countermeasures (torpedo decoys).
SIGNAL-TO-NOISE RATIO (SNL) How loud a contact is relative to the surrounding ocean noise. Measured in decibels.
SIOP WARPLAN The Top Secret plan for waging a major sea war, including the use of nuclear weapons. SIOP stands for Single Integrated OP-Plan.
SKIMMER Derogatory term for a surface ship or sailor of a surface ship. Surface ships only skim the surface.
SKIPJACK CLASS Early fast attack submarine class that was the first to feature a streamlined cylindrical hull.
SLBM Submarine launched ballistic missile.
SNAKE PATTERN A torpedo search pattern in which the torpedo wiggles, tracing a snake shaped pattern. Enables narrow search beam to cover more ocean by forcing the torpedo to look on either side of its heading.
SNAPSHOT A quick reaction torpedo shot, usually only done when fired on first.
SNCP (SPECIAL NAVY CONTROL PROGRAM) Top Secret series of coven submarine operations.
SNORKEL A mast designed to bring air into the submarine so that the air-breathing diesel generator can use it for combustion when the reactor is scrammed.
SOLENOID An electrical device that causes motion by the action of an electromagnet. Used in remotely actuated valves.
SOLUTION A contact’s range, course, and speed. A great mystery when using passive sonar. Determining the solution requires maneuvering own ship and doing calculations on the target’s bearing rate. Can be obtained manually or with the fire-control computer.