USCG Exam PracticeTides and currents — predictions and corrections
A vessel has a draft of 8 feet. The charted sounding at a shoal is 6 feet. The predicted height of tide at the time of passage is 3 feet. What is the underkeel clearance?
- ✓ 1 footCorrect
- B. 5 feet
- C. 2 feet
- D. The vessel will ground; there is no underkeel clearance
Why A is correct
Per Bowditch Ch. 9 §904, actual depth equals charted sounding plus predicted height of tide: 6 + 3 = 9 feet. Underkeel clearance equals actual depth minus draft: 9 - 8 = 1 foot.
Cited:Bowditch Ch. 9 §904