What defines a vessel restricted in her ability to maneuver?

A vessel restricted in her ability to maneuver is defined by the nature of her work that limits her navigation capabilities. This includes vessels engaged in activities such as underwater work, cable-laying, dredging, or towing operations, where their ability to change course or speed may be significantly hindered. This working status creates a scenario where these vessels cannot safely navigate in the same manner as others, hence they are categorized under this specific definition.

The other options do not accurately capture this definition. For example, merely being a vessel in open water does not inherently limit maneuverability. Size alone, such as being less than 20 feet, does not dictate how a vessel can operate or maneuver; rather, it is the specific tasks being performed that contribute to restrictions. Similarly, a vessel lacking an engine may indeed be difficult to maneuver, but this condition alone does not meet the criteria for defining a vessel restricted in its ability to maneuver. The key factor is the nature of the work performed by the vessel, which can significantly affect its navigational capabilities.