THERE! A word added in hailing any part of a ship; as, "Forecastle there!" "Mast-head there!"
THERE AWAY! A phrase accompanied by pointing on a bearing, or to an object in sight. Thereabout, in that quarter.
THERMOMETER. An instrument to measure the amount of heat by the expansion of a fluid (generally quicksilver) contained in a glass bulb, in connection with which is a hermetically closed tube, up which the fluid rises as the heat increases. This tube is graduated differently in different countries.
THERMOMETRIC SAILING. A scheme for detecting the approach to shoal water by the diminution of temperature, and found to be useful in some places, such as the Agulhas and Newfoundland Banks; in the latter a difference of 20° has been observed, on quitting the Gulf Stream and gaining soundings in 100 fathoms.
THICK-AND-DRY FOR WEIGHING! To clap on nippers closely, just at starting the anchor from the ground.
THICK AND THIN BLOCK, or Fiddle-block. A block having one sheave larger than the other, sometimes used for quarter-blocks.
THICK STUFF. Sided timber, or naval planks, under one foot, and above 4 inches in thickness.
THIEVES' CAT. A cat o' nine tails having knots upon it, and only used for the punishment of theft.
THIMBLE. An iron ring with a concave outer surface to contain snugly in the cavity a rope, which is spliced about it. Its use is to defend the rope which surrounds it from being injured by another rope, or the hook or a tackle which passes through it.
THIMBLE-EYES. Are thimble-shaped apertures in iron-plates where sheaves are not required; frequently used instead of dead-eyes for the topmast-rigging, futtock-plates, and backstays in the channels.