You are underway in an area where the...

Question 1 of 2707066636ee928f7522a1c51a4bd

You are underway in an area where the charted depth is 8 fathoms. You compute the height of tide to be -4.0 feet. The draft of your vessel is 5.0 feet (1.52 meters). You determine the depth of the water beneath your keel to be __________.

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Question 1 of 27070

🔍 Key Concepts

• Charted depth vs. actual depth – how tide height changes the water depth shown on the chart • Negative tide height – what does a minus sign mean in relation to chart datum? • Under-keel clearance – total water depth minus vessel draft

💭 Think About

• First, convert the charted depth in fathoms to feet, then adjust it by the computed height of tide. Is the tide adding to or subtracting from the charted depth in this case? • Once you find the actual depth of water, think about how to get from that number to the depth "beneath your keel" when your vessel has a known draft. • Compare your final under-keel clearance with the answer choices and check which one is reasonable given that the tide is below chart datum.

✅ Before You Answer

• Be sure you know that 1 fathom = 6 feet before you start calculating. • Confirm whether a negative tide height means you should add or subtract from the charted depth. • After you find the total water depth, remember to subtract the vessel’s draft to get the depth under the keel, not just the total depth.