MACHINABILITY–The ease with which a metal may
be turned, planed, milled, or otherwise shaped.
MAIN CONDENSER–A heat exchanger that converts
exhaust steam to feedwater.
MAIN DRAIN SYSTEM–A system used for pumping
bilges; consists of pumps and associated piping.
MAIN INJECTION (SCOOP INJECTION)–An
opening in the skin of a ship through which cooling
water is delivered to the main condenser and main
lube oil cooler by the forward motion of the ship.
MAKEUP FEED–Water of required purity for use in
ship’s boilers This water is needed to replace water
lost in the steam cycle.
MALLEABILITY–That property of a material that
enables it to be stamped, hammered, or rolled into
thin sheets.
MANIFOLD–A fitting with numerous branches that
directs fluids between a large pipe and several
smaller pipes.
MANUAL BUS TRANSFER (MBT)–A device that
will transfer electrical power from the normal
power supply to an alternate power supply,
manually.
MECHANICAL ADVANTAGE (MA)–The advantage
(leverage) gained by the use of devices, such as a
wheel to open a large valve, chain falls and block
and tackle to lift heavy weights, and wrenches to
tighten nuts on bolts.
MECHANICAL CLEANING–A method of cleaning
the fire sides of boilers by scraping and wire
brushing.
MICROMHOS–Electrical units used with salinity
indicators to measure the conductivity of water.
MICRON–A unit of length equal to 1 millionth of a
meter.
MOTOR GENERATOR SET–A machine that
consists of a motor mechanically coupled to a
generator and usually mounted on the same base.
NIGHT ORDER BOOK–A notebook containing
standing and special instructions from the
engineering officer to the night engineering officers
of the watch.
NITROGEN-An inert gas that will not support life or
combustion.
NONFERROUS METALS–Metals that are composed
primarily of some element or elements other than
iron (usually nonmagnetic).
OIL KING–A petty officer who receives, transfers,
discharges, and tests fuel oil and maintains fuel oil
records; certified to test and treat boiler water and
feedwater.
OIL POLLUTION ACTS–The Oil Pollution Act of
1924 (as amended), the Oil Pollution Act of 1961,
and the Federal Water Pollution Control Act of 1970
prohibit the overboard discharge of oil or water that
contains oil, in port, in any sea area within 50 miles
of land, and in special prohibited zones.
ORIFICE–A small opening that restricts flow, such as
an orifice plate in a water piping system.
OVERLOAD RELAY–An electrical protective device
that automatically trips when a circuit draws
excessive current.
OXIDATION–The process of various elements and
compounds combining with oxygenThe corrosion
of metals is generally a form of oxidation; for
example, rust on iron is due to oxidation.
PANT, PANTING–A series of pulsations caused by
minor, recurrent explosions in the firebox of a ship’s
boilerUsually caused by a shortage of air.
PARTS PER MILLION (PPM)–Comparison of the
number of parts of a substance with a million parts
of another substanceUsed to measure the salt
content of water.
PITOMETER LOG–Device that indicates the speed of
a ship and the distance traveled by measuring water
pressure on a tube projected outside the ship’s hull.
PLASTICITY–A property that enables a material to be
excessively and permanently deformed without
breaking.
PREHEATING–The application of heat to the base
metal before it is welded or cut.
PRIME MOVER–The source of motion, such as a
turbine or an automobile engine.
PUNCHING TUBES–Process of cleaning the interiors
of tubes.
PURPLE-K POWDER (PKP)–A fire - extinguish-
ing agent.
PYROMETER–An instrument used for measuring
temperatures.
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