What should be done if the water depth is 15 feet?

When determining the appropriate length for an anchor line, it is essential to consider the depth of the water and the ratio typically recommended for anchoring effectively. A general rule of thumb is to use an anchor line that is at least three times the depth of the water. This ratio provides sufficient scope, which allows the anchor to set properly and hold the vessel securely in place, especially in changing conditions such as wind or current.

In this case, with a water depth of 15 feet, using an anchor line of 45-60 feet fulfills the requirement of being three times the water depth. This length allows the anchor to be deployed at an appropriate angle and depth, increasing its effectiveness in securing the vessel. It also accounts for additional factors like tidal changes, wave action, and the specific anchoring surface.

Using a shorter line, such as 30-45 feet or even 15-20 feet, would not provide the necessary scope for an effective hold and may result in the boat drifting or the anchor not holding properly. Thus, employing an anchor line within the 45-60 feet range is the most prudent choice for a water depth of 15 feet.