POWDER-CHESTS, certain small boxes, charged with powder and a quantity of old nails, or splinters of iron, and fastened occasionally on the decks and sides of a ship, in order to be discharged on an enemy who attempts to seize her by boarding. See that article.
These cases are usually from 12 to 18 inches in length, and about 8 or 10 in breadth, having their outer or upper-part terminating in an edge. They are nailed to several places of the quarter, the quarter-deck and bulk-head of the waist, having a train of powder which communicates with the inner apartments of the ship, so as to be fired at pleasure to annoy the enemy. They are particularly used in merchant-ships, which are furnished with close quarters to oppose the boarders. See Close-Quarters.
PRAM, or PRAME, a sort of lighter, used in Holland and the ports of the Baltic sea, to carry the cargo of a merchant-ship along-side, in order to lade her: or to bring it ashore to be lodged in the store-houses after being discharged out of the vessel.
PRATIC, pratique, a term used in the European ports of the Mediterranean sea, implying free intercourse or communication with the natives of the country, after a limited quarantine has been performed, in consequence of a voyage to Barbary or Turkey.
PREVENTER, an additional rope, employed at times to support any other, when the latter suffers an unusual strain, particularly in a strong gale of wind; as the
Preventer-brace, a temporary brace, fixed occasionally to succour the main or fore-yard of a ship, but particularly the latter, when it is charged with a greater effort than usual, and which, it is apprehended, the common standing braces would not be able to support. See Brace.
Preventer-shrouds, and Preventer-stays, are applied, in the same manner, to serve the same purposes; and may be easily understood by referring to the articles Shroud and Stay.
PRICKING the chart, pointer, the act of tracing a ship’s course upon a a marine chart, by the help of a scale and compasses, so as to discover her present situation.
Pricking the sails, the act of stitching two cloths of a sail together along the space, comprehended between the two edges, or selvages, that overlay each other. Or, it is the sowing a middle-seam between the two seams which are employed to unite every cloth of a sail to the next adjoining. This operation is rarely performed till the sails have been worn for a considerable time, so that the twine, with which they were originally sewed, is become very feeble and incapable of resisting the efforts of a strong gale of wind.
PRIMING, the train of powder which is laid from the opening of the touch-hole, along the cavity of the pan, in order to fire the piece: also the operation of laying this train. See the articles Cannon and Exercise.