The Lock and Dam system on the Mississippi River is a source of endless fascination. In the distance one sees a tug boat pusher with 15 barges - 3 wide and 5 deep moving downriver toward the lock. It looks like a floating storage island. The M/v Ed Renshaw itself is 158 feet long and 45 feet wide. With 15 lashed-together barges it constitutes a vehicle more than 900 feet by 105 feet, pushing into a lock that is 110 feet wide and 600 feet long. It requires a masterful feat of pinpoint piloting to accomplish the task. This load also requires a two-stage operation to complete. Lock 10 only rises or falls 7 feet, but does so in a mere 7 minutes. And all river traffic is accorded the same passage, whether its a tiny fishing boat or massive towboats and barges. A few hours earlier, the M/v Tom Behringer moved upriver with a smaller load.