Ship Driver Navigation and Chart Reading 1 — Questions and Answers
Question 1: What does a nautical chart's depth sounding number represent?
- Distance to nearest port
- Water depth at low tide (Correct answer)
- Height above sea level
- Speed limit in the area
Correct answer: Water depth at low tide
Nautical chart depth soundings represent the water depth measured at mean lower low water (MLLW), the average of the lowest daily tides.
Question 2: What color are safe water marks (mid-channel buoys) in the US system?
- Green and white
- Red and green
- Red and white vertical stripes (Correct answer)
- Black and yellow
Correct answer: Red and white vertical stripes
Safe water marks (mid-channel buoys) feature red and white vertical stripes, indicating navigable water on all sides.
Question 3: When entering a US port from seaward, where should red buoys be?
- On your left (port side)
- On your right (starboard side) (Correct answer)
- Dead ahead
- Behind you
Correct answer: On your right (starboard side)
The US IALA-B system follows 'red right returning,' meaning red buoys are kept to starboard when entering port from sea.
Question 4: What is a compass rose on a nautical chart used for?
- Measuring distances
- Determining water depth
- Reading true and magnetic bearings (Correct answer)
- Identifying shipping lanes
Correct answer: Reading true and magnetic bearings
A compass rose shows both true north (outer ring) and magnetic north (inner ring) so mariners can convert between the two for navigation.
Question 5: What does the abbreviation 'RK' indicate on a nautical chart?
- Rocky bottom (Correct answer)
- Restricted channel
- Radar reflector keeper
- River kilometer marker
Correct answer: Rocky bottom
'RK' on a nautical chart indicates a rocky bottom or rock hazard, warning mariners of potential grounding danger.
Question 6: A vessel's DR (dead reckoning) position is calculated using which information?
- GPS coordinates alone
- Last known position, speed, course, and elapsed time (Correct answer)
- Radar and depth sounder readings
- Visual landmarks only
Correct answer: Last known position, speed, course, and elapsed time
Dead reckoning calculates an estimated position by advancing the last known fix using speed, course, and time without external references.
Ship Driver Navigation and Chart Reading 1
What does a nautical chart's depth sounding number represent?