Maritime and Marine Marine Navigation and Charting 3

Question 1

What is 'dead reckoning' in marine navigation?

Accepted Answer

Estimating current position from a known fix using course, speed, and elapsed time

Answer

Dead reckoning (DR) is the process of estimating one's current position by advancing a known past position based on recorded speed, heading, and elapsed time, without reference to external fixes.

Question 2

What instrument is used to measure the altitude of celestial bodies above the horizon in celestial navigation?

Accepted Answer

Sextant

Answer

A sextant is a precision optical instrument used to measure the angular altitude of a celestial body above the visible horizon, which is the fundamental observation in celestial navigation.

Question 3

In celestial navigation, why is an accurate chronometer essential?

Accepted Answer

To provide accurate Greenwich Mean Time for calculating longitude

Answer

An accurate chronometer provides precise Greenwich Mean Time (GMT), which is essential for longitude calculations since one degree of longitude corresponds to exactly four minutes of time.

Question 4

What is a 'Line of Position' (LOP) in navigation?

Accepted Answer

A line on a chart along which the vessel's position is known to lie based on a single observation

Answer

A Line of Position is derived from a single navigational observation (such as a bearing, range, or celestial sight) and represents all possible positions where the vessel could be located at that moment.

Question 5

What effect does 'leeway' have on a vessel's navigation?

Accepted Answer

It causes lateral drift due to wind, creating a difference between heading and actual track

Answer

Leeway is the sideways drift of a vessel caused by wind pressure on the hull and superstructure, resulting in the vessel's actual track differing from its steered compass heading.

Maritime and Marine Practice Test

Maritime and Marine Practice Test

Maritime and Marine Marine Navigation and Charting 3