The Greenville Gage reads 10.6 feet. The high point of your towboat is 54 feet above water. What is the vertical clearance as you pass under the Greenville Highway Bridge?
• Greenville Gage reading vs. bridge clearance table for that bridge • How to calculate available vertical clearance when water level is higher or lower than the reference level • Difference between height of your towboat and available clearance under the bridge
• Ask yourself: Is the clearance under the bridge increasing or decreasing when the gage reading goes up? • What reference water level is the bridge clearance usually based on, and how would you adjust that clearance for the actual gage reading of 10.6 feet? • Once you know the actual clearance under the bridge, what simple subtraction do you perform using your towboat’s height of 54 feet?
• Verify what the charted bridge clearance is referenced to (e.g., low water reference, a specific gage height) for the Greenville Highway Bridge. • Be sure you are adjusting the bridge clearance in the correct direction (adding or subtracting from the reference clearance) based on whether the river is higher or lower than the reference level. • Confirm that your final step is the clearance under the bridge minus the 54‑foot towboat height, not the other way around.
No comments yet
Be the first to share your thoughts!