Keeping a research vessel on schedule proves to be a tiring task
Posted September 14, 2012
Those not familiar with the workings of large ships may fail to appreciate the challenges involved in keeping to a schedule. Neither the ships themselves nor the seas they cross care much for human planning; they have their own timetables. They also enforce their own version of Murphy’s Law.
The Gould had completed the transfer of hazardous materials from Palmer Station to the United States, as it does every second year. The visit north also provided the ship an opportunity to complete a routine “yard period,” where repairs and inspections can be made. It’s during such periods that the U.S. Coast Guard certifies the ship safe to operate.
With less than 48 hours remaining on its scheduled stay in Port Fourchon, La., the ship’s starboard propeller tangled, quite literally, with an old tire. It was of that variety commonly seen hanging from the sides of piers, docks, and even small vessels. Such tires serve as fenders, meaning that they are supposed to protect hulls from damage.
But when one works itself loose and falls into the water, it becomes a potential menace.
The tire of our tale became a problem when the Gould — having taken on fuel at a special pier that serves just that need — started its short trip back to a berth at the Edison Chouest Offshore (ECO) facility. (ECO is the company that crews, maintains, and manages both U.S. Antarctic Program research vessels.) There was cargo waiting to be brought aboard, as well as other loose ends that needed to be dealt with before the ship could commence its month-long journey back to Punta Arenas, Chile. Everything had been on schedule, until the tire made its presence known.
That moment occurred precisely as the ship began to pull away from the fueling pier. Without warning, one of the engines shut down, just as they are designed to do if a propeller becomes entangled with a submerged object, so that damage to the propulsion system might be prevented.
A tire was assumed to be the culprit as soon as the engine stalled, but confirmation was needed. To that end, a diver was called in to make an inspection. The diver arrived with gear in tow, and had a long chat with the captain. A strategy was devised, and a wet suit was donned.
Neither the lateness of the hour nor the turbidity of the water would keep him from making his survey. The water was so murky that nothing beyond its surface could be seen. A visual confirmation would be impossible, but a tactile check would suffice.
The diver joked that he didn’t bother to open his eyes on such dives, because he wouldn’t be able to see anything anyway. While “professional diver” may sound like a romantic occupation to some, nobody on deck appeared to envy this fellow his choice of careers at that particular moment.
That first dive didn’t take long. It was easy enough to confirm that a tire was, in fact, the source of all the trouble. It had been sucked into the narrow space between the propeller and something called a “kort nozzle,” a cylindrical duct that the propeller sets in. The nozzle increases the efficiency of the propeller, and offers some protection when operating in icy seas. In this case, though, the nozzle served as just one more element in the conspiracy to knock the ship off schedule.
A tire was certainly the problem, but that knowledge alone did not imply a quick or easy solution. Tires selected for use as fenders are often very large, and not easily cut. The lack of visibility complicated matters, especially given the need to adhere to a long list of safety precautions. Such constraints narrowed the options significantly, but attempts were made nonetheless.
In fact, efforts continued well into the night. Unfortunately, the tire proved to be a tenacious sparring partner. Some time after midnight it was determined that the problem would have to wait until morning. The tire had won — but this was just round one.
The bell rang for round two at first light. The Gould was still tied up to the fueling pier, but that was about to change. The decision had been made to move back to the ECO facility using the other propeller. The ship’s propulsion system has at least two of everything, so such a journey presented no great challenge. More importantly, ECO has many resources that might prove useful. Upon arrival, the Gould tied up off the stern of another ECO ship, the Holiday.
That vessel is designed to assist offshore drilling rigs when moving their massive anchors. This means that the ship is equipped with very powerful winches, and just such a device might be the key in making the recalcitrant tire relent. More meetings were hastily called, and new tactics devised. The concerns were obvious: the need to remove the tire in a timely manor, the need to avoid damage to the Gould, and the need to keep everyone involved out of harm’s way.
The diver was back after what must have been a very short sleep. He took part in the planning, and then returned to his murky workshop to place a line on the tire. He emerged from the water after a time, and all appeared ready. Everyone was warned that the line was about to be put under great tension, and everyone responded by moving to a safe position.
The powerful winch was engaged, and quickly proved to be the tire’s better. The tire surrendered with a sudden jolt. The tremendous energy contained in the taught line was released in an instant, snapping as a giant rubber band might. The tire was free, and with a few more turns of the winch, it came to rest on the aft deck of the Holiday. No sign of fight remained in the tire, and the Gould appeared to be back on schedule.
A final dive confirmed that nothing of the tire remained on the propeller, shaft, or nozzle, and that the ship was free of damage. The incident falls well short of being a defining episode in anyone’s career. Nor does it mark an important point in the history of either vessel. In fact, just the opposite is true.
What makes it an event of interest is that it constitutes “just another day” aboard ship. It serves to highlight the kind of effort, creativity, and professionalism required to keep these vessels available to do the work that really counts.
Dean Hancock is a technical editor for the USAP, currently aboard the research vessel Laurence M. Gould as it transits from Port Fourchon, La., to Punta Arenas, Chile. He spent 10 years in the U.S. Navy , where he worked in shipboard engineering. He has also worked for the U.S. Geologic Survey doing cartography and Geographic Information Systems.
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