Question

A vessel's position should be plotted using bearings of __________.

a) True north
b) Magnetic north
c) Compass north
d) Relative bearing

Answer 1

A vessel's position should be plotted using bearings of true north. This provides a constant reference for navigation, unlike magnetic or compass north which are subject to variations.

Step-by-step explanation:

The vessel's position should be plotted using bearings of true north (a). True north, also known as geographic north, is the direction along the Earth's surface towards the geographic North Pole. The north pole of a compass needle is attracted to the south magnetic pole of Earth, which is located near the geographic North Pole of Earth, but magnetic north can vary and is different from true north.

When expressing direction, bearings are often used. A bearing is a direction relative to a fixed point, usually defined in degrees clockwise with respect to North. For instance, a bearing of 110° indicates that the direction has been rotated 110° clockwise relative to North. It is important to note that the compass points towards the magnetic north and not true north, which can lead to slight discrepancies in navigation if not accounted for.

In the context of navigation, using true north is preferred as it provides a constant reference that is not subject to magnetic variations that magnetic and compass north are susceptible to.

Answer 2

The most accurate bearing for plotting a vessel's position is based on True North (option a). A compass points towards Magnetic North, which requires adjustments for magnetic declination to correctly navigate using True North.

Step-by-step explanation:

A vessel's position should be plotted using bearings from a fixed point that is typically a universally recognized directional reference. The most precise and universally recognized reference is True North, which is the direction along the Earth's surface towards the geographic North Pole.

The north pole of a compass needle is attracted to the south magnetic pole of Earth, which is located near the geographic North Pole of Earth. However, a magnetic compass points towards Magnetic North because it aligns with the Earth's magnetic field, which is slightly different from True North due to variations in the Earth's magnetic field. Therefore, the most accurate bearing for plotting a vessel's position would be based on True North.

A compass doesn't always point towards True North because of this variation, known as magnetic declination, which can change depending on your location. Navigators have to adjust for this variation to navigate accurately. A magnetic compass proves useful in navigation, but adjustments must be made to accommodate for the discrepancies between Magnetic North and True North.