Panama Canal Transit
Left ship is in lock where water level has not changed. Right ship is higher water that will be same as when she exits.
Costa ship now has been lifted to the higher water level.
Right hand lock is now draining water to lower level to get ready for the next ship
Gate is closing behind cruise ship as it departs lock.
Left lock now draining to left side to drop to same level as right side. The little bridge is moved aside every time the gate opens. It takes a while to maneuver the ships so the little bridge is available probably 90% of the time.