Page 41 - Electronic Navigation Cyber Book

of the water flow may give a wrong representation of the vessels speed.
This is minimized by careful siting of the sensor as well as by calibrating
the instrument while installation.
Pitch and roll also give rise to errors however these are reduced by
having an electrical time constant that is longer than a period of vessel
motion.

A well-adjusted log can have an accuracy of better than 0.1 percent of
the speed range

This type of log can give only speed through water and is greatly affected
by the current flowing under the ship. However if the water is stationary
at an anchorage there will be no speed shown.
In all the above logs the flow of water past and under the hull play a major
part in the accuracy of the readings.

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