42. The highest point on your towboat is 67 feet above the water, and the Helena Gage reads +22.3 feet. What is the vertical clearance when you pass under the A-span of the Helena Highway Bridge?

The vertical clearance is calculated by subtracting the current river stage reading from the charted bridge clearance, then subtracting the towboat's air draft. Applying this process with a charted clearance of 119.4 feet, a current stage reading of +22.3 feet, and a towboat height of 67 feet results in a vertical clearance of 30.1 feet.