USCG Exam PracticeApplying tide corrections to charted depth
A charted sounding shows 18 feet. The tide tables indicate the current water level is 3 feet above MLLW. What is the actual depth of water at that location at this moment?
- A. 15 feet
- B. 18 feet
- ✓ 21 feetCorrect
- D. The charted depth cannot be adjusted without knowing the tidal range.
Why C is correct
Charted soundings are referenced to MLLW (Bowditch Ch. 4 §403). When the tide is above MLLW, that height of tide is added to the charted depth: 18 ft + 3 ft = 21 ft actual depth. Subtracting would give the depth at a lower stage, not the present depth.