The Practical Navigation and Seaman's New Daily Assistant

The Practical Navigation and Seaman's New Daily Assistant

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1794 edition. Excerpt: ...loaded with Lead fufficient to make it fwim upright in the Water. To this Log is fattened a long Line of about 150 Fathoms, called the Log-Line, which is divided into certain equal Spaces, called Knots, each of which ought to bear the fame Proportion to a Nautical Mile (60 of which make a Degree) that Half a Minute does to an Hour, that being the Time allowed for the Experiment. They are called Knots, becaufe at the End of each of them there is a Piece of Twine with Knots in it, reeved between the Strands of the Line; thefe Pieces of Twine fhew how many Knots run out in Half a Minute, and confequently the Ship's Rate of Sailing per Hour. Mr. Norwood, and feveral other able Mathematicians, have found that a Degree of a great Circle upon the Earth contains about 367200 Englifh Feet, therefore a Nautical Mile being the & Part of 367200 Feet, that is, 6120 Feet, and fince Half a Minute is T'- Part of an Hour, the Length of a Knot on the LogLine ought to be the Tis Part of 6120 Feet, or 51 Feet. But as for the mod Part the Ship's Way is found, by Experience, to be really more than that given by the Log, and as it is fafer to have the reckoning before the Ship than after it, therefore 50 Feet may be taken as the proper Length of each Knot, and thefe Knots fubdivided into ten Fathoms, each of 5 Feet, which is certainly the belt adapted for Praflice, and will correfpond with all the Tables and Inftruments ufed in Navigation, as they are decimally divided, and, confequently, the Ship's Run determined with greater Eafeand Certainty. But fome experienced Commanders find, that the allowing 50 Feet to a Knot, generally makes the Ship a-head of the Reckoning; and, to avoid Danger, moftly divide the Log-Line into Knots of 7 or 7 i Fathoms, of 6 Feet...show more

Product details

  • Paperback | 116 pages
  • 189 x 246 x 6mm | 222g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236485785
  • 9781236485786