You are underway in a vessel with a draft of 6.0 feet. You are in an area where the charted depth of the water is 4 fathoms. You would expect the depth of water beneath your keel to be approximately __________.

Correct Answer: Option A — 18 feet

One fathom equals 6 feet, so a charted depth of 4 fathoms equals 24 feet. Subtracting a 6-foot vessel draft yields 18 feet of water remaining beneath the keel. This standard USCG depth computation applies basic conversion factors from Bowditch.