USCG Exam PracticeTides and currents — predictions and corrections
A vessel must transit a channel where the charted sounding is 10 feet and the vessel's draft is 11 feet. The navigator determines the minimum predicted height of tide required to transit safely with at least 1 foot of underkeel clearance. What is that minimum predicted height of tide?
- A. 11 feet
- ✓ 2 feetCorrect
- C. 3 feet
- D. 1 foot
Why B is correct
Bowditch Ch. 9 §904 states actual depth equals charted sounding plus predicted height of tide, and underkeel clearance equals actual depth minus draft. Required actual depth = draft + minimum clearance = 11 + 1 = 12 feet. Required tide height = 12 - 10 = 2 feet.
Cited:Bowditch Ch. 9 §904