A New and Accurate Method of Finding a Ship's Position at Sea, by Projection on Mercator's Chart ...: The Principles of the Method Being Fully Explained and Illustrated by Problems, Examples, and Plates, with Rules for Practice, and Examples from Actual Observation |
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A New and Accurate Method of Finding a Ship's Position at Sea, by Projection ... Thomas H Sumner No preview available - 2016 |
A New and Accurate Method of Finding a Ship's Position at Sea, by Projection ... Thomas H. Sumner No preview available - 2008 |
Common terms and phrases
assumed latitudes bearing body called centre change of station chart circle consequent correction corresponding course curve dead reckoning declination determined diff difference of azimuth difference of longitude direction distance double altitudes east or west elapsed equal altitude error of latitude error of longitude example finding the apparent given gives greater Greenwich hour intersection known land latitude by dead less light log rising longitude by chronometer manner mean azimuth meridian method miles minutes motion namely Navigation noon noted observation parallel of equal parallel of latitude passes planets plate pole pole of illumination position practical problem projected proper reference respective resulting right angles rules sailed second observation ship ship's position shows side sphere straight line subtracted sun bears sun's taken true latitude tude turned watch
Popular passages
Page 49 - December, within 40 miles, by dead reckoning, of Tuskar light, the wind hauled SE. true, making the Irish coast a lee shore; the ship was then kept close to the wind and several tacks made to preserve her position as nearly as possible until daylight, when, nothing being in sight, she was kept on ENE. under short sail with heavy gales. At about 10...
Page 49 - Having sailed from Charleston, SC, 25th November, 1837, bound to Greenock, a series of heavy gales from the Westward promised a quick passage ; after passing the Azores, the wind prevailed from the Southward, with thick weather; after passing Longitude 21°...
Page 24 - , crosses the second Sumner line will be the position of the ship at the time of the second observation, and a, her position at the first observation.
Page 44 - Note. After the vernal equinox, when in north latitude, observations may be often taken when the sun bears to the northward of the E. and W. points ; and in south latitude, after the autumnal equinox, when he bears to the southward of them; also when the latitude and declination are of the same name, and the declination is greater than the Latitude in. The method of using this table will be best shown by AN EXAMPLE.
Page 49 - N. of the dead reckoning; this also placed the ship still further ENE, and still 27 nautical miles further; these three positions were then seen to lie in the direction of Small's light. It then at once appeared, that the observed altitude must have happened at all the three points and at...
Page 49 - ENE, and still 27 nautical miles further ; these three positions were then seen to lie in the direction of Small's light. It then at once appeared, that the observed altitude must have happened at all the three points and at Small's light, and at the ship, at the same instant of time ; and it followed, that Small's light must bear ENE, if the Chronometer was right. Having been convinced of this truth, the ship was kept on her course. ENE, the wind being still SE, and in less than an hour, Small's...
Page 49 - Irish coast a lee shore; the ship was then kept close to the wind, and several tacks made to preserve her position as nearly as possible until daylight, when, nothing being in sight, she was kept on ENE under short sail with heavy gales. At about 10 AM an altitude of the sun was observed, and the Chronometer time noted; but having run so far without any observation, it was plain the Latitude by dead reckoning was liable to error, and could not be entirely relied on. Using, however, this Latitude,...
Page 52 - A small circle of a sphere is one whose plane does not pass through the centre of the sphere, and consequently divides the sphere into two unequal parts.
Page 3 - Naval Library and Institute,' Navy Yard, Boston, April 30th, 1843. I certify the above to be a true Copy of the Report, (Copy.) (Signed) W. WHELAN, Recording Secretary. Navy Yard, Boston, 9th May, 1843.
Page 81 - ZZ' is greater than 180° (or must be subtracted from 360°) when the great circle which passes through the positions in the heavens, in which the bodies were observed, passes also below the elevated pole, the bodies being also observed on different sides of the meridian. In all other cases ZZ
Bibliographic information
| Title | A New and Accurate Method of Finding a Ship's Position at Sea, by Projection on Mercator's Chart ...: The Principles of the Method Being Fully Explained and Illustrated by Problems, Examples, and Plates, with Rules for Practice, and Examples from Actual Observation |
| Author | Thomas H. Sumner |
| Edition | 3 |
| Publisher | T. Groom & Company, 1851 |
| Original from | the University of Michigan |
| Digitized | Nov 23, 2005 |
| Length | 90 pages |
| Export Citation | BiBTeX EndNote RefMan |