Navigation & Charting Flashcards

What is the primary purpose of a danger bearing?

Answer: To establish a bearing that must not be crossed to avoid a hazard

A danger bearing is a predetermined compass bearing to a fixed object; the navigator ensures the vessel stays on the safe side of this bearing to avoid a charted hazard.

When using parallel rulers to transfer a course line to the compass rose, the transfer should always be made to the:

Answer: Inner ring of the compass rose for true courses

The outer ring of a chart's compass rose shows true directions referenced to geographic north, while the inner ring shows magnetic directions.

Which chart scale is considered the largest scale for harbor navigation?

Answer: 1:20,000

A scale of 1:20,000 (or smaller ratios like 1:10,000) is a large-scale chart showing fine detail suitable for harbor and port navigation.

What action corrects for leeway when plotting a course to steer?

Answer: Adjust the course into the wind by the estimated leeway angle

Leeway is the sideways drift of a vessel caused by wind; the navigator compensates by steering upwind (into the wind) by the estimated leeway angle.

A bearing of 000°T means the object is located:

Answer: Due north of the observer

A true bearing of 000° (or 360°) indicates the object is directly due north of the observer, as true bearings are measured clockwise from true north.

What is the charted symbol for a wreck that is considered dangerous to surface navigation?

Answer: A crossed lines symbol with 'Wk' label

A dangerous wreck on a nautical chart is depicted with crossed lines and labeled 'Wk', indicating a hazard that extends near enough to the surface to threaten vessels.

When applying tide corrections for safe passage over a bar, the navigator should use:

Answer: Predicted tidal height for the date and time added to the charted depth

To find actual depth at a bar, add the predicted tidal height for the specific date and time to the charted sounding (which is referenced to MLLW datum).