USCG Exam PracticeApplying tide corrections to charted depth
A vessel drawing 9 feet approaches a shoal with a charted depth of 7 feet. The predicted tide height at the time of transit is +2.5 feet. What is the vessel's underkeel clearance?
- ✓ 0.5 feetCorrect
- B. 2.0 feet
- C. 4.5 feet
- D. 2.5 feet
Why A is correct
Actual depth = charted sounding + tide height = 7 + 2.5 = 9.5 feet. Underkeel clearance = actual depth minus draft = 9.5 - 9.0 = 0.5 feet. (Bowditch Ch. 9 §904)
Cited:Bowditch Ch. 9 §904