Question 1361Navigation General

The correct answer is D) 12 1/2 hours. The rotary current, also known as a tidal current, completes one full cycle (360 degrees) in approximately 12 1/2 hours off the East coast of the United States. This is due to the semi-diurnal tidal pattern, where there are two high tides and two low tides each day, with a period of about 12 hours and 25 minutes between consecutive high or low tides. The other options are incorrect because they do not accurately represent the typical period of a rotary current in this region. A 2 1/2 hour or 3 1/2 hour cycle would be too short, while a 6 1/4 hour cycle would not account for the full 360-degree rotation.