Compass
A compass can be used to help steer when land is out of sight and a boat operator is confused or disoriented.
Navigation out of sight of land using the Polar Star.
Out of sight of land they used astral navigation. The got as far afield as the Canary Islands and Cornwall.
A negative sight in surveying occurs when the vertical line of sight from the instrument to the target is below the instrument's horizontal axis. This can result in incorrect measurements and lead to inaccuracies in the survey data. Negative sights should be avoided by ensuring that the instrument is properly leveled before taking measurements.
Coastal navigation is transport by sea or inland waterways. The coast is rarely out of sight and so position can be confirmed by land features and navigation marks, such as light houses and buoyage.
well i can tell you what it is but im not quit sure what you mean by an example.... it is a optical instrument for viewing objects that are above the level of direct sight; mostly used in submarines
Of or pertaining to sight; used in sight; serving as the instrument of seeing; as, the visual nerve., That can be seen; visible.
Of or pertaining to sight; used in sight; serving as the instrument of seeing; as, the visual nerve., That can be seen; visible.
they don't the help you eye sight
This sight is very useful
Dead Reckoning
Azimuth