To determine the depth of the water, what must you add to your depth finder reading?

To accurately determine the depth of the water beneath your vessel, you need to add the draft of the vessel to your depth finder reading. The draft refers to the distance between the waterline and the bottom of the hull (keel) of the vessel, indicating how deep the vessel sits in the water.

When you read the depth off your depth finder, it gives you the distance from the water's surface to the seabed directly below the transducer. Because the vessel's hull extends below the waterline due to its draft, you must account for this distance to ascertain the actual depth of water that accommodates your vessel. By adding the draft to the depth finder reading, you can effectively see how much clearance there is between the vessel's keel and the bottom, which is crucial to avoid grounding, especially in shallow waters.

The other options do not relate directly to calculating the actual depth in relation to your vessel’s positioning. The weight of the vessel, the height of the wave, and the load of the vessel do not serve as metrics for adding to the depth measurement provided by the depth finder.