Oil spills after two barges strike Mississippi River bridge

[HooptieWagon]

10. The passage under a bridge is in the channel.

The bridge piers are vertical, and protected by fenders (usually heavy wooden walls). While the sides of the passage may have a bit less vertical clearance under the bridge than the center, water depth in the channel under the bridge should be fairly constant across the width between the fenders. Usually, you proceed under the bridge in a straight line perpendicular to the bridge. I was pointing out that a shoal in the channel before or after the bridge may have required a course change, and if improperly timed would cause contact with the bridge. A similar situation would exist if the bridge was located at a curve in the channel (really bad planning).
Those barge/tug combinations are pretty limited in their manuvering capabilities. Take a close look at the wooden fenders sometime, they're usually pretty tore up as a result of repeated contact from barges.