How to Measure the Draft of a Boat

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The draft of a boat is one of the most important things to know while boating. Simply put, the draft of a boat is a measurement of how far the boat’s hull will extend underneath the water. When you have determined the draft of a boat, you can use this information to make wise decisions about the depth of the water you chose to navigate. For example, if the boat has a draft of 6 feet, boating in water with a depth of 7 feet is probably too risky. Since the draft of a boat cannot be observed while you are actually underway, you need to measure the draft before you embark.

Start by adding the maximum amount of cargo, or weight that you would typically carry on the boat. Among other factors, the amount of weight on board effects the draft of a boat; the more weight, the further down the boat sits in the water, increasing the draft of the boat. In addition to avoiding waters that are too shallow, measuring the draft with the maximum amount of weight that would usually be carried on the boat is a good way to play it safe.

Identify the lowest part of the boat’s keel. The keel is a term describing the bottom of your boat, though vessels vary in the type of keel they have. For example, the draft of a motor boat will likely be less than that of a sailboat, as sailboats often have a fixed keel that extends like a fin from the bottom of the boat, increasing the draft of the boat.

Measure the distance from the boat’s waterline, (where the side of the vessel meets the water) to the lowest part of the keel that you have identified. Record this number in feet or centimeters. You have measured the draft of your boat.

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