Question 1 of 2921866636eea28f7522a1c51b539

You are to sail from Elizabethport, N.J., on 22 May 1983, with a maximum draft of 28 feet. You will pass over an obstruction in the channel near Sandy Hook that has a depth of 26.5 feet. The steaming time from Elizabethport to the obstruction is 1h 40m. What is the earliest time (ZD + 4) you can sail on the afternoon of 22 May and pass over the obstruction with 2 feet of clearance?

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Question 1 of 29218
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You are to sail from Elizabethport, N.J., on 22 May 1983, with a maximum draft of 28 feet. You will pass over an obstruction in the channel near Sandy Hook that has a depth of 26.5 feet. The steaming time from Elizabethport to the obstruction is 1h 40m. What is the earliest time (ZD + 4) you can sail on the afternoon of 22 May and pass over the obstruction with 2 feet of clearance?

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🔍 Key Concepts

• Under-keel clearance: Required depth = ship draft + desired clearance • Tidal height calculation from tide tables for Sandy Hook on 22 May 1983 (afternoon high tide and surrounding hours) • Time of transit: You depart Elizabethport and arrive at the obstruction 1h 40m later, so departure time + 1h 40m must match a suitable tide height

💭 Think About

• First compute the minimum total water depth you need over the obstruction to have 2 feet of clearance. What is that depth? • From the charted depth (26.5 ft) and the required depth you just computed, how many feet of tide above chart datum do you need? • Looking at the tidal curve for the afternoon of 22 May, at what time(s) is the tidal height at or above that required value, and which of those times minus 1h 40m gives you a realistic afternoon sailing time?

✅ Before You Answer

• Be sure you correctly add draft + desired clearance to get the minimum depth requirement • Confirm that you’re using the right time zone (ZD + 4) and the afternoon tide on 22 May, not the morning or a different date • Double-check that the time you select is the departure time, which is 1h 40m earlier than the time your ship passes over the obstruction