USCG Exam Practice · Chart symbols and abbreviations (Chart No. 1)
On a US nautical chart, soundings are referenced to which datum?
- AMean Sea Level (MSL)
- BMean Lower Low Water (MLLW)✓ correct
- CMean High Water (MHW)
- DMean Low Water (MLW)
Why B is correct
US charts reference soundings to Mean Lower Low Water (MLLW), representing the average of the lower of the two daily low tides. The sounding unit (feet, fathoms, or metres) is stated in the chart title and must be verified before plotting. (Bowditch Ch. 4 §403)
Cited:Bowditch Ch. 4 §403
Drill more Chart symbols and abbreviations (Chart No. 1) questions
Every CaptainsGround answer cites the rule it tests — verified, not guessed. Try a free 5-question drill, no sign-up.
More practice questions
- On a US nautical chart, soundings are referenced to which datum?
- On a US nautical chart, the letter code 'M' annotated near an anchorage symbol indicate…
- The charted position of a lighthouse is indicated by which cartographic symbol?
- On a US nautical chart, soundings are referenced to which datum?
- On a US nautical chart, soundings are referenced to which datum?
- You are the master of a towing vessel and wish to fix your vessel's position. Under 33 …