Kirby Corp. added to its fleet of articulated tug-barges (ATBs) last year when Signal International delivered the tugs Jason E. Duttinger and Captain Donald Lowe Sr. , coupled with the barges Winna Wilson and Margo Dale, respectivel y, to the Houston-based company. These ATBs transport coal from Plaquem ines Parish in southeast Louisiana to Duke Energy’s Crystal River Complex on Florida’s west coast.
Bill Withers, senior vice president of sales at Kirby Ocean Transport, said the new ATBs give Kirby a more efficient and reliable means of serving its customers. “We’ve had a supply contract providing coal to power plants in Crystal River for many, many years,” he said from Houston. “Our equipment got old, and we replaced it with more modern and economical articulated barges. Thirty-four years ago, barges were towed. ATBs are efficient, new technology and they handle well in inclement weather.”
Kirby Ocean Transport is a division of Kirby Corp.
ATBs combine the economies of tugboats and barges with the speed and weather endurance of ships. Because their hinged connections let the tug pitch independently of the barge, ATBs handle much better in coastal waters than towed barge systems.
Ocean Tug & Barge Engineering (OT&BE), based in Milford, Mass., designed the two tugs and their matched barges, which measure more than 600 feet when connected. Kirby contracted with Signal, based in Mobile, Ala., for Jason E. Duttinger and Winna Wilson in April 2011. They were built in Signal’s yard in Orange, Texas, and were delivered in May 2013. In August 2011, Kirby exercised an option for the second ATB, which was delivered by Signal in August 2013. Kirby paid roughly $47 millio n for each of the two ATBs.
When Jason E. Duttinger and Winna Wilson were christened in New Orleans on Oct. 30 of last year, they had already been in service for a while. Kirby’s ATBs make four to six round trips a month between Plaquemines Parish and Crystal River, Withers said. At the Louisiana coal terminal and the Florida delivery point, the unit can turn around in as little as a day. But in February, Withers said the ATBs had been making four round trips a month because of bottlenecks at Crystal River while new gantry cranes were installed.
Kirby Ocean Transport moves coal from Louisiana to the Crystal River utilities under a contract slated to expire in 2020. In addition to arrival by barge, coal also reaches Crystal River by rail, Withers said. The energy complex contains four coal-fired plants, along with a now permanently-closed nuclear facility. Plans were to shut down coal-fired Units 1 and 2, which were built in the 1960s, in 2016, but Duke Energy decided to run them until mid-2018. Meanwhile, Duke is considering replacing the Crystal River nuclear unit with a natural gas-fueled plant. Duke Energy is headquartered in Charlotte, N.C.
Kirby’s new ATBs have advantages over vessels the company used earlier to move coal. The tugs are powered by EMD 710 main engines, a newer, more efficient generation that replaced the EMD 645s.
Built by Electro-Motive Diesel, the EMD 710 is a relatively large, two-stroke diesel engine with a maximum speed of 900 rpm. The tugs’ twin EMD 12-710G7C-TC 3,000-hp engines turn 135-inch, three-bladed propellers through Reintjes WAF 3455 5.091:1 reduction gears and Nautican nozzles.
The tugs have EMI hydraulic steering systems. Palfinger 12,125-pound capacity cranes are installed on their decks.
The tugs are 125 feet long, with a beam of 42 feet and a maximum draft of 22 feet. The barges are 490 feet long, with a 90-foot beam and a draft of 36 feet, and are equipped with Schottel SRJ220 Pump Jet bow thrusters. The tugs and barges are linked by Articouple KVC-6068 systems. Cargo capacity for the barges is 897,905 cubic feet.
In addition to containing the latest technology, the tugs were built with the crew’s comfort in mind. “The kitchen appliances are similar to something you’d see in a new home,” Withers said. “They have nice quarters, Internet, television and a workout room.”
Duttinger has an eight-man crew now, including the captain. The vessel’s six staterooms include two single sleeping quarters and four doubles, for a total of 10 bunks. The captain has his own stateroom.
The cabins are outfitted with desks with Wi-Fi connections. And who does the cooking on board? “They take turns,” Withers said.
Duttinger, a member of the OT&BE Atlantic V class, is a descendant of a group of five tugs built from 2002 to 2010, according to Bob Hill, president and principal naval architect at Ocean Tug & Barge Engineering.
“The Duttinger’s beam was taken out to 42 feet so she could float into a shallow channel on her trade route and carry more fuel doing so,” Hill said. The vessel is fitted with Nautican propeller nozzles and triple, high-aspect-ratio rudders. “Working with the Winna Wilson’s Schottel Pump Jet bow thruster, this combination can capably navigate the difficult approach to the terminal where the unit discharges her coal cargo,” Hill said.
The tug’s hull shape and the barge’s stern shape are complementary designs so that speed and maneuverability are greatly enhanced. “We design all of our ATBs to outperform the IMO 751 maneuvering standards for ships,” Hill said. “This was particularly important for these units, given the route they take into their discharge port.”
“We developed the barge stern design in concert with our partner, Corning Townsend of CT Marine, and with Taisei Engineering, which provided the Articouple connection system,” Hill said. “The first barge of this shape was designed in 2003 and is highly successful, so we applied the same principle to this unit.” The bow design and shape are CT Marine designs adapted to Winna Wilson and her sister by Ocean Tug & Barge Engineering.
Kirby’s new barges have two very large cargo holds, with equally big hold openings, making it easier for shoreside cranes to work them.
“These large openings allow the barges to carry outsized project cargo or containers,” Hill said. Since walking on the outboard side of the hatch coamings is dangerous in foul weather, the barges have port and starboard internal passages below deck. Crewmembers can move between forward and aft machinery spaces on the barge without going outside.
Kirby needs more articulated units. Early this year, Kirby Offshore ordered a 10,000-hp ATB from Nichols Brothers Boat Builders in Washington state, to be mated with a Gunderson-built tank barge. The tug is slated for delivery next year. Kirby contracted with Greenbrier Co.’s Gunderson Marine division in Oregon for an articulated oil-and-chemical tank barge for 2015 delivery, with an option for a second unit. Kirby will spend $75 million to $80 million on the entire ATB — designed by Guarino & Cox LLC in Covington, La. Kirby plans to charter this new ATB to one of its customers for a four-year period, with an option to extend.