Riding a Panama Canal water tractor
Sailboats transiting the Panama Canal often share a lock with one of the many Panama Canal Commission tugboats. The tugs constantly transit the canal locks, on their way to or from assisting larger vessels. Recently, I was line-handling aboard a sailboat in transit, and the sailboat was directed to side-tie to one of the tugs. Once secured to the tug, I was off duty as line-handler for about 15 minutes. I noticed the tug master outside on the tug's bridge deck. The tug, looking like a big black-and-red bathtub toy, fascinated me. On a whim I yelled up to the tug master: "May I come aboard?" "Yes," he replied, waving me over. A deckhand led the way.
The tug master and I shook hands, and he took me into the air-conditioned pilot house. I noticed many controls. How did the buttons and levers work and how were they used? I started asking questions. The tug master was surprised at my interest. "Sailors," he said, "usually don't pay any attention to the tugs." Meanwhile, the canal lock had filled with water, and the tug and the side-tied sailboat had risen 35 feet. I had to end my brief tour and return to the sailboat.
Back on the sailboat, the Panama Canal advisor we were required to have on board noticed my excitement about the tugboat. He said, "Are you interested in riding the water tractor? Apply for guest status, and be aboard for a full day's work." He went on to tell me a "ride-along" would last for an eight-hour shift, with the tug working up and down in the locks, pushing and pulling the huge ships. I jumped at the opportunity to ride a working tug. The advisor gave me a name and telephone number and said, "Call this person. He can arrange it."
It was not easy. After numerous telephone calls to three departments, I put on my best clothes, went for a personal interview with the director of public affairs, and was finally granted a tour. The day at last arrived. I bounded into the office of Norman Watkins, superintendent of the Tow Boat Branch of the Panama Canal Commission. It was 0700in my excitement, I was an hour early. After a short orientation, I signed release forms and was ready to go.
Mr. Watkins scanned the schedule of the 17 working tugs and tug masters serving within the department. He decided to put me on the tug boat D.P. McAuliffe, named after a long-standing, recently retired chief administrator.
McAuliffe is one of five newer, omni-directional "water tractors" built by Houma Fabricators of Houma, La. She is 95 feet long and 34 feet wide, has a 17-foot draft, and weighs 285 tons.
The Voith Schneider cycloidal propulsion system drives the water tractor. Voith propulsion consists of twin General Motors turbocharged diesels at 1,500 hp each. The diesels connect to circular rotor plates that are flush with the ship's bottom. Five propeller blades, five feet long,18 inches wide, and shaped like spade rudders, protrude downward from each rotor plate. These blades rotate somewhat like an egg beaterthey also change pitch on their axes, thereby providing steerage and power.
I met the crew that runs McAuliffe: a tug master, an engineer, and three line-handlers. When the van arrived we rode together to the launch station. The tugboat crew and I boarded the pilot launch along with the engineers, line-handlers, and a pilot for the next large ship transiting the canal.
The pilot launch ferried us out to McAuliffe, which was tethered to the stern of a super-containership moving slowly through the Galliard Cut of the Panama Canal. McAuliffe, being towed by the containership at this point, waited to provide assistance if needed. The new crew and I clambored aboard. McAuliffe's departing crew turned her over without missing a beat and left on the launch.
Felipe Joseph, the tug master, invited me into McAuliffe's air-conditioned pilot house. I sat in a plush leather swivel chair facing one of two identical control stations. Each station consisted of a steering wheel, two propeller pitch controls, an engine throttle and a bank of lights, buttons, buzzers, and switches. A UHF radio microphone hung on the side.
After explaining the controls and communications equipment, Joseph summoned the engineer. The engineer took me for a tour of the engine room. We wound our way to its watertight door where we put on protective ear devices. The engine noise is so loud that the engineer must communicate using a bank of lights. He watches the lights and interprets their signals to follow the directions of the tug master.
The twin General Motors diesel engines are 10 feet long, five feet wide, and five feet high. Sitting side by side, the engines connect directly to the circular rotor plates for the Voith propellers. Five additional diesel engines in the room generate electrical power for the huge winches on deck and for the firefighting water pumps (McAuliffe also doubles as a fireboat). The room itself was spotlessly clean, brightly lit, and, compared to the air-conditioned pilot house, extremely warm.
After looking at the engine room I walked up to the crew quarters at deck level. The crew invited me to join them at their long table.
I returned to the pilot house where the containership loomed in the windows. With towing lines in place, McAuliffe would remain attached to the containership until the canal widened at Gamboa. We were in the Gaillard Cut, the narrowest part of the canal, where all large or "super" ships are required to have tugboats ready for assistance. Furthermore, larger vessels may not pass one another in this cut and must transit it in daylight hours only.
The tethered McAuliffe and her super ship continued. As the cut ended and we reached Gamboa, the pilot on the containership radioed McAuliffe. Over the speaker we heard the command: "McAuliffe, release." Our tugboat master responded immediately with "McAuliffe will release." He pushed the whistle button, producing a "Tweeeeet tweet tweet" (one long, two short).
The crew of both ships jumped into action. The tug crew first released the tension on the two hawser lines (2.5-inch-diameter braided nylon line as thick as your wrist) by reversing the winches. The ship's crew then removed the lines from their bollards and lowered the hawsers to McAuliffe's deck by way of small messenger lines.
Tugboat master Joseph then gave one long whistle from McAuliffe, and the tug backed away. He grabbed the radio microphone, called the containership pilot, and said: "McAuliffe free." I watched as the containership faded into the distance of Lake Gamboa. McAuliffe pulled over to the tug station at Gamboa, and waited for her next task. She planned to turn around and meet a different ship going south (the way we had just come).
McAuliffe would again accompany a ship through the narrow Galliard Cut, positioning her entry into the Pedro Miguel Lock on the way to the Pacific Ocean.
The containership Zim America approached Gamboa. McAuliffe left the dock and prepared to meet her. As we slipped by Zim, Joseph simply shifted the two propeller pitch levers, and the omni-directional tug scooted sideways and tucked in behind Zimall without turning around or slowing. McAuliffe then continued in Zim's direction.
McAuliffe's line-handlers again manhandled the two huge hawsers, using smaller lines for messengers. Zim's crew looped the hawsers around her bollards, and McAuliffe's winches pulled them tight. Joseph called the pilot on Zim, letting him know the tug was connected by saying "McAuliffe in service." The Zim's pilot responded: "Roger, roger, McAuliffe in service." On McAuliffe, we had a two-hour wait as the Zim pulled us down the Gaillard Cut.
We approached the Pedro Miguel Locks, and another tug, M.L. Walker, joined us. Walker attached to Zim's starboard bow; McAuliffe was still on the stern. The pilot aboard Zim America would direct placement of the huge containership in the locks, using the two tugs to manipulate and nudge her into proper position.
The radio squawked with the pilot's commands. Pilot: "McAuliffe, three whistles." The tugboat master responded: "McAuliffe, three whistles back." The whistle tooted three short blasts as McAuliffe gave full power in reverse, pulling Zim almost to a stop. The pilot aboard Zim issued the next command: "McAuliffe, stop." The tugboat master repeated "McAuliffe, stop." Joseph pulled the throttle back with one hand, set the pitch levers with the other, and gave a long "toot" on the whistle. The pilot issued an order for the tug Walker: "Walker, give me one whistle." The tugboat master responded: "Walker, one whistle." We heard Walker toot one short whistle, and I watched the black exhaust spew from Walker's stack. Walker had barely started her push to port when the next command rang out: "Walker, stop."
More orders ensued for McAuliffe, then more for Walker. Back and forth the orders flew: acknowledged, signaled with whistle toots, and followed precisely. Slowly, the tugboats maneuvered the containership into the lock. Once in place, the line-handlers on Zim threw heaving lines to the mule line-handlers on the side of the canal. The mules, electric trains on the locks, pull cables attached to the transiting vessel. The cables keep the vessel centered as she moves from lock to lock.
The final command came to McAuliffe and Walker: "McAulifferelease. Walkerrelease. Thank you, gentlemen." Both tugs acknowledged their release and simultaneously whistled one long "Tooooot." As we powered off I realized my day aboard McAuliffe was ending. McAuliffe pulled up to the pilot station dock, crabbing in sideways between two other tugs already there.
I got off McAuliffe and waved good-bye to Joseph and the crew. To the crew the eight-hour shift had been work; to me it had been play. Using flawless communication and precision teamwork, the canal tugboats and their crews perform tirelessly, 24 hours a day, 365 days a year. Forty giant ships, unable to move freely in the narrow canal, need assistance every day. The Panama Canal water tractors ensure each of them a smooth and incident-free transit.