Your vessel has a draft of 34 feet. On 8 October 1983 you wish to pass over an obstruction near Jaffrey Point, NH, that has a charted depth of 31 feet. Allowing for a safety margin of 3 feet, what is the earliest time after 0900 DST (ZD +4) that this passage can be made?

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Accepted Answer

Option B: 1029. Vessel draft (34') plus safety margin (3') minus charted depth (31') equals a needed tide height of 6 feet. Interpolate the Jaffrey Point tide tables on 8 October 1983 after 0900 DST to identify when the rising tide hits 6 feet.