Once the ship is completely in the lock and gate is closed, the water level is reduced to match the other side. The other gate is then opened and the tugboats guide the ship from the Panama Canal onto open waters of the Atlantic Ocean.
Under the old lock system at Panama Canal, tugboats’ engagement with ships has been limited to guiding them in open waterways and to the entrance of the locks, where powerful locomotives known as “mules” take over, latching on and keeping the vessels in place as the water level is raised or lowered.
There are no mules in the new locks setup. Instead tugs approach a ship, latch on at both the bow and stern and accompany it inside the 1,400-foot locks. With the lock doors closed on a 1,200-foot New Panamax, there’s little room to operate for the roughly 90-foot tugs positioned both fore and aft.
The shipping vessels run on their own propulsion throughout, and are under the control of a canal pilot who goes on board to steer. Communication between the tugs and the pilot are key.
A tugboat gently guides a large ship through the Aqua Clara Lock, Panama Canal