Dead reckoning
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In navigation, dead reckoning is the process of calculating the current position of a moving object by using a previously determined position, or fix, and incorporating estimates of speed, heading, an
Dead reckoning navigation tools in coastal navigation
British P10 Magnetic Compass with dead reckoning navigation tools
Chip log
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A chip log, also called common log, ship log, or just log, is a navigation tool mariners use to estimate the speed of a vessel through water. The word knot, to mean nautical mile per hour, derives fro
Dead reckoning
…of recorded heading, speed, and time. Speed can be determined by many methods. Before modern instrumentation, it was determined aboard ship using a chip log. More modern methods include pit log referencing engine speed (e.g. in rpm) against a table of total displacement (for ships) or referencing one's…
Model of chip log and associated kit. The reel of log-line is clearly visible. The first knot, marking the first nautical mile is visible on the reel just below the centre. The timing sandglass is in the upper left and the chip log is in the lower left. The small light-coloured wooden pin and plug form a release mechanism for two lines of the bridle. From the Musée de la Marine, Paris.
Chip log in the 18th century
Taffrail Log Rotator
Negus Taffrail Log