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Appendix I, Continued
FIX.—A relatively accurate position
determined without reference to any former
position.
FLAGHOIST.—A display of flags used to
indicate a signal or a group of signals.
FLAGSTAFF.—A small vertical spar at
the stem on which the ensign is hoisted.
FLOOD TIDE.—Tide rising or flowing
toward land.
FOG.—A visible assemblage of numerous
tiny droplets of water or ice crystals
formed by condensation of water vapor in
the air with the base at the surface of
Earth.
FORETRUCK—The highest point of the
forward mast.
FRONT.—The intersection of a frontal
surface and a horizontal plane.
GAFF.—A small spar abaft the mainmast
from which the national ensign is flown
when the ship is under way.
GEOGRAPHICAL POSITION.—That
point on Earth at which a given celestial
body is in the zenith at a specified time.
Any position on the earth defined by
means of its geographical coordinates.
GNOMONIC PROJECTION.—A map
projection in which points on the surface
of a sphere or spheroid, such as Earth, are
conceived as projected by radials from the
center to a tangent plane.
GREAT CIRCLE.—The intersection of a
sphere and a plane through its center
meridian; angular distance west of the
Greenwich celestial meridian; the arc of
the celestial equator, or the angle at the
celestial pole, between the upper branch of
the Greenwich celestial meridian and the
hour circle of a point on the celestial
sphere, measured westward from the
Greenwich celestial meridian through 360°.
GREENWICH HOUR ANGLE.—Local
hour angle at the Greenwich Meridian.
GREENWICH MEAN TIME.—Local
mean time at the Greenwich Meridian; the
arc of the celestial equator, or the angle at
the celestial pole, between the lower
branch of the Greenwich celestial meridian
and the hour circle of the mean sun,
measured westward from the lower branch
of the Greenwich celestial meridian
through 24 hours; Greenwich hour angle of
the mean sun, expressed in time units, plus
12 hours.
GROUND WAVE.—That portion of a
radio wave in proximity to, and affected
by, the ground, being somewhat refracted
by the lower atmosphere and diffracted by
the surface of Earth.
GUN SALUTE.—Blank shots fired to
honor a dignitary or in celebration.
GYROCOMPASS.—A compass having
one or more gyroscopes as the directive
element and tending to indicate true north.
GYRO REPEATER.—That part of a
remote indicating gyrocompass system that
repeats at a distance the indications of the
master gyrocompass.
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