DICTIONARY OF

Palowa 246 Parallel of Latitude
Palowa. Sailing craft of China Seas. Schooner rigged, whale-boat stern, about 70 ft. long.
Pampero. Line squall of Argentina and Uruguay. Marked by thunder, lightning and rain.
Pan. A spoken radiotelephony message prefixed with the word Tan' indicates that an urgent
message concerning the safety of a vessel, aircraft or person is about to be made.
Panama Canal Tonnage. Computation for tonnage /of ships passing through Panama
Canal. Approximates nett registered tonnage, but has important differences.
Panama Lead. Circular fair leads at ends of a ship. Necessary when being towed by shore
locomotives in Panama Canal.
Pancake Ice. Small, circular sheets of newly-formed ice that do not impede navigation.
Pangaia. Mozambique vessel mentioned by Hakluyt. 'Like a barge, with one matsail of
coconut leaves. The hull sewed together with the rinds of trees, and pinned with wooden
pins.'
Panting. A more or less rhythmic in and out movement of ship's plating due to variations in
water-pressure. Particularly noticeable forward when pitching.
Panting Beam. Beam placed athwartships to support shipside plating against panting
stresses.
Panting Stress. Stress, due to water pressure variations, that tends to cause an in and out
movement of ship's underwater plating.
Parallactic Angle. Angle between hour circle of an observed heavenly body and the arc of a
circle of altitude intercepted by the body and observer's zenith. Is angle X in PZX triangle.
Also called 'Angle of Position'.
Parallactic Inequality. Variation in tidal phenomena that is due to variation in Moon's
distance from Earth.
Parallax. Apparent change in position of an observed object when due to change in position
of observer. 2. Parallax of sextant is equal to angle, at an observed object, between a line
from centre of index glass and another line from horizon glass. Error is quite negligible
unless observed object be very near.
Parallax in Altitude. Difference between altitude of heavenly body above sensible horizon
and its altitude above rational horizon. Is maximum when body is in sensible horizon.
Parallel Index. Lines parallel to the bearing-marker on a radar display, useful for passing an
intended distance from a point of land or vessel.
Parallel of Altitude. Small circle parallel to plane of horizon and passing through all points
having the same altitude.
Parallel of Declination. Small circle of celestial sphere that passes through all points having
the same declination.
Parallel of Latitude. Small circle of terrestrial sphere, parallel to Equator, passing through
all positions having the same latitude.