Locks

The Great Loop route includes crossings of land masses and cruising on lakes and rivers above sea level.  To move a boat to a higher level or lower it back, lock systems were developed.  On this journey, over 150 locks will be encountered and the highest water elevation will be 840 feet above sea level.  The first lock on the northern journey was entering the Dismal Swamp Canal, which is 8 feet above sea level.  A small elevation compared to some on the Tennessee River that raise/lower boats 80 feet, but still a lock that illustrates the function.  Some locks on the Trent-Severn Canal in Canada are constructed with quite different systems, including one that lifts the boats out of the water, moves them over land, and places them into another waterway.

The timing of the cruise to the South Mills lock went as planned, arriving at 10:40 am, for the 11:00 am scheduled locking.

Conversations with the lockmaster via the marine VHF radio, made the request to lock through and he opened the gates to the lock pool.

After entering the lock pool and tying to the wall, the lockmaster closes the gates to the lock.  The higher water level mark can be seen on the lock wall.

The lockmaster then walks to the other end of the lock to operate the gates on the end with the higher water level.  One person operates the lock, and some locks in Canada are operated totally by hand.

The lockmaster opens valves in the upside gates to allow water to flow into the lock at a controlled rate to bring the lock pool to the same height as the higher level water, in this case, the Dismal Swamp Canal.

As the water rises in the pool, the lines securing the boat need to be shortened.  This usually requires two crew to handle lines at the bow and the stern.  With the water rushing into the pool, the currents try to move the boat around, necessitating constant management of the lines.  This crew member looks quite relaxed -- the photo was taken after the pool reached its highest level.

After the water level rises to the higher level, the gates are opened to allow the boat to leave the lock.

In this case, the lock was followed by a lift bridge that had to be opened.  The lockmaster handles this duty also.  You can see the back of his truck on the road as he drives from the lock to the bridge.

The bridge is opened to allow the boat to continue its course along the waterway.  On this day, due to our early schedule, Last Dance was the only boat to transit the locks.

At the north end of the canal, another lock lowered the boat back to sea level, again, accompanied by another bridge opening.  Two locks transited, about 148 to go.