Chart Navigation & Plotting · Tides — Vertical Clearance
A bridge shows a charted vertical clearance of 65 ft (referenced to mean high water). At a state of tide 4 ft below MHW, the available clearance is:
- A61 ft
- B69 ft✓ Correct
- C65 ft
- D60 ft
Explanation
Vertical clearance is charted to MHW, the conservative (lowest) value. When the tide is 4 ft below MHW, the clearance increases by 4 ft: 65 + 4 = 69 ft.
Authority: NOAA charts; Chart No. 1 (vertical clearance datum)
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