190 WHALE-FISHERY. 



The requisites peculiar to a Greenland ship, the 

 intention of wliich is to afford additional strength, 

 consist of doubling, and sometimes trebling, and 

 fortifying. 



The terms " doubling" and " trebling," are expres- 

 sive of the number of layers of planks which are ap- 

 plied to the exterior of a frame of timbers ; hence a 

 ship which has one additional series of phinks, is said 

 to be doubled; and such ships as are furnished with 

 two, or part of two additional layers of planks, are said 

 to be trebled. Doubling generally consists of the ap- 

 plication of 2 or 2^ inches oak plank near the bow, di- 

 minishing towards the stern to perhaps half that 

 thickness, and extending, in one direction, from the . 

 lower part of the main- wales, to within six feet (per- 

 pendicular) of the keel forward, and to within eight 

 or nine feet abaft ; and, in the other direction, that 

 is, fore and aft wise, from the stem to the stern post. 

 Doubling is used for producing an increase of 

 strength ; and, at the same time, for preserving the 

 outside or main planks of the ship, from being in- 

 jured by tlie friction of passing ice. Trebling, 

 which commonly consists of 1^ to 2 inches oak 

 plank, is generally confined to the bows of the ship, 

 and rarely extends farther aft than the fore chains, 

 or chess-tree. It is seldom applied, but to second 

 rate ships. Its principal use is to increase the 

 strength of the ship about the bows ; but it also 



