You will be loading in Boston Harbor to a maximum draft of 32'06". The charted depth of an obstruction in the channel near Boston Light is 30 feet and you wish to have 3 feet of keel clearance. The steaming time from the pier to the obstruction is 01h 05m. What is the latest time (ZD +4) you can sail on 17 May 1983 and meet these requirements?
Official USCG Answer & Rule Citation
Correct Answer: Option B — 1728
Maximum draft (32.5') plus required keel clearance (3') minus charted depth (30') dictates a needed tide of 5.5 feet. Find the falling tide level matching this height in Boston tables and subtract the 1h 05m steaming time for latest departure.
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