58. The Natchez Gage reads 20.6 feet. The high point on your towboat is 47 feet above the water. What is the vertical clearance as you pass under the Natchez Highway Bridge?

The vertical clearance is calculated by subtracting the river stage and the towboat's air draft from the bridge's clearance at 0 feet on the gage. The Natchez Highway Bridge has a clearance of 125.6 feet at 0.0 feet on the Natchez Gage. With a river stage of 20.6 feet, the actual clearance is 105.0 feet. Subtracting the towboat's height of 47 feet results in a vertical clearance of 58.0 feet.