DICTIONARY OF

Pitometer Log 255 Pledge
Pitometer Log. Submerged log actuated by pressure set up by ship's advancing through
water. Speed is indicated directly; distance run is indirectly obtained by additional
mechanism.
Pitting. Localised corrosion causing small pits to form in metal.
Pivoting Point. That point, inside a vessel, on which she turn when under helm.
P.L.A. Port of London Authority.
Plain Sail. Sail with no reef taken in it.
Plain Sailing. 'Plane Sailing'.
Plait. Yarns or small line intertwined to make sennit, gaskets or foxes.
Plan. Chart covering a small area on a very large scale. There is no distortion, relative
distances and positions being maintained.
Plan Position Indicator. See Cathode Ray Tube.
Plane Chart. Chart constructed on a supposition that surface of Earth is flat in charted area.
Except for small areas at Equator it would be erroneous. Is not used in modem chart
construction. Mercator charts were, at one time, called 'plane charts'.
Plane of Ecliptic. Plane of celestial sphere passing through centres of Earth and Sun.
Plane Sailing. That method of solving certain navigational problems on assumption that
Earth's surface, in the area concerned, is a plane.
Planet. Satellite of Sun that reflects Sun's light. Excluding minor planets there are eight,
Earth not being reckoned. Those revolving inside Earth's orbit are termed 'minor planets',
those outside Earth's orbit being 'major planets'.
Planetarium. Mechanised model of Solar System, not to scale, used for illustrating
movements of planets around Sun, constellations, etc.
Planetoid. A minor planet, or asteroid.
Plank. Technically, length of timber more than 9 inches wide and from 1 to 4 inches in
thickness.
Planking Clamp. Implement for bending a plank to rib of a wooden vessel, and holding it in
place until fastened.
Plank on Edge Type. Name given to deep and narrow yachts that developed between 1852
and 1876, about. Name is often given to deep and narrow vessels in general.
Plank Sheer. Plank resting on top timbers of ribs or frames.
Plankton. Mass of minute animal and vegetable organisms that exists in the sea below the
surface and above the bottom.
Planter. Tree trunk with its root in bed of a river and its top just below water level. May be a
navigational hazard in some rivers of western America.
Plat. Old name for a chart. 2. Plait.
Plate. Iron or steel sheet forming part of ship's deck or hull plating. 2. Iron or steel bar or
band - such as 'Chain Plate'.
Platform. Plated deck, in engine-room, from which the engines are tended and controlled. 2.
Name given to 'Orlop Deck'.
Pledge. Length of oakum used when caulking a seam.