Moran updates 93-foot workhorse for the Tier 4 eraJul 3, 2018 10:40 AM
BENSON GEORGE MORAN | Moran Towing Corp., New Canaan, Conn.
Benson George Moran is Moran Towing’s first Tier 4 tugboat.
Over the past two decades, 92- and 93-foot tugboats have become the backbone of Moran Towing’s ship-assist fleet. With Benson George Moran, that venerable class has undergone its first update since 2011.
The 6,772-hp vessel, named for Moran chairman Paul Tregurtha’s grandson, is the company’s first with EPA Tier 4-rated propulsion. The 93-by-38-foot tug is 12 percent more powerful than its predecessors. It’s also the first newly built Moran tug with Caterpillar engines and Rolls-Royce z-drives.
Washburn & Doughty built the tug at its East Boothbay, Maine, shipyard. Bruce Washburn, the firm’s naval architect and executive vice president, said the proven design required a series of modifications — largely to accommodate the aftertreatment modules and urea tanks.
Moran assigned Benson George Moran to Port Arthur, Texas. Since arriving in early 2018, it has earned strong reviews from Moran captains and local pilots.
Capt. Clint Campbell watching the radar in thick fog off Port Arthur, Texas.
“It can do the work of two conventional tugs,” said Capt. Mark Taylor of the Sabine Pilots. “That frees up boats for our harbor to move other vessels, which goes a long way toward making us more efficient.”
“That particular tractor tug is the strongest in our harbor,” he continued. “It’s the biggest, strongest, most versatile tug we have.”
Port Arthur-Beaumont is a major petroleum and chemical port, home to the Motiva Port Arthur refinery, one of the largest facilities in the U.S. The region attracts numerous towboats pushing tank barges, deep-draft tankers and the occasional bulker.
Assist tugs working in Port Arthur typically meet inbound ships south at the Texaco Island intersection southwest of the city then escort them to their destination. There, a second assist tug arrives for docking. During the escort, tugs are often asked to slow the ships while they pass other moored vessels.
Unlike its predecessors outfitted with EMD mains, Benson George Moran is equipped with Caterpillar engines.
“We’re constantly being used to slow them down, then when they get past the dock the ship speeds up again, then they might slow down and speed up again several more times,” said Moran Vice President Steve Kelly, who runs the company’s Port Arthur office. “Depending how far up the Neches River they are going, this can happen three or four times, maybe five or six times.”
“It’s all about being careful and not throwing a big wake in the water,” he continued.
Benson George Moran’s design can be traced back to Moran’s 92-by-32-foot tugs introduced nearly two decades ago. Over time, Washburn & Doughty lengthened the hull by a foot and the beam by 6 feet. These changes allowed for larger engines capable of providing more than 6,000 hp, better escort stability and roomier crew spaces.
Washburn & Doughty built 12 93-by-38-foot EPA Tier 3 tugs for Moran between 2011 and 2017, beginning with James A. Moran and ending with Clayton W. Moran, which the company assigned to its Norfolk operation. That 6,000-hp vessel has twin EMD 12-cylinder mains and Schottel drives.
Washburn said the latest 93-foot platform evolved in several important ways. For one thing, the main deck was raised by 12 inches, creating additional space in the engine room for Tier 4-required equipment. These systems inject diesel exhaust fluid (DEF) into the exhaust stream to reduce nitrogen oxides (NOx) and particulate matter (PM) emissions.
Moran’s 93-foot tugboat class evolved from an earlier line of 92-footers first introduced nearly two decades ago.
More importantly, the additional freeboard also improved escort performance. “We did a (computational fluid dynamics) study on the hull to try to nail down what we could do to optimize the escort performance or indirect performance of the boat,” Washburn said. “It came up that adding 12 inches of freeboard would be optimal. We didn’t really gain anything after that.”
Adapting the design to meet Tier 4 standards had its challenges. Among them, the vessel required a continuous supply of compressed air and an additional system for pumping the DEF. Stainless-steel tanks also were added to hold DEF.
“People have had their first crack at (Tier 4 designs) and are seeing what they like and what they don’t like,” Washburn said, noting that Benson George Moran was the yard’s first Tier 4 boat. “And it was the first boat our Cat dealer had done, so there was some learning going on all around.”
Washburn & Doughty is building a second 6,772-hp Tier 4 tugboat for Moran due later this year, and a similar Tier 4 tugboat for G&H Towing of Houston.
Aft-facing FFS fire monitors on the FiFi-1-rated Benson George Moran.
From an operations standpoint, adapting to Tier 4 required training around DEF handling and spill response, Kelly said. But in general he considers it a non-event. “So far there really haven’t been any major hurdles to overcome.”
Propulsion on Benson George Moran consists of twin Caterpillar 3516 Tier 4 mains each rated for 3,386 hp. The engines turn Rolls-Royce US 255 z-drives with 110-inch stainless-steel props in nozzles. Bollard pull is guaranteed at 80 tons ahead, although crews are seeing higher numbers on their line tension meters, Kelly said.
Electrical power comes from twin John Deere 99-kW generators, and a Caterpillar C32 engine drives the vessel’s FFS fire pump capable of 11,750 gallons per minute. Twin stern-facing FFS 1200 monitors installed aft of the wheelhouse can each disperse 5,284 gpm. The tug has a FiFi-1 rating.
Like its most recent sibling outfitted to handle neo-Panamax ships, Benson George Moran has a 75-hp Markey DEPCF-52 electric hawser winch on the bow with the render-recover feature to maintain constant line tension. The drum is spooled with 400 feet of Cortland 9.5-inch line. On the aft deck is a CEW-60 electric capstan.
Markey Machinery’s DEPCF-52 bow winch spooled with 400 feet of Cortland 9.5-inch Plasma line.
Moran has standardized the wheelhouse layout across its newbuilds, making Benson George Moran virtually identical to its earlier sister tugs. It features Furuno electronics and closed-circuit TV cameras installed throughout the vessel. LED bulbs are installed in crew spaces and used with navigation lights and floodlights.
Benson George Moran has a standard crew of four, with a captain, mate, engineer and AB/deck hand. The tug has four cabins — giving each crewmember their own space during normal operations — with total berthing for six. The captain and mate’s rooms are located on the main deck, while the other two staterooms are below.
Benson George Moran has earned a reputation as a comfortable boat. The tug has flat-screen TVs and high-speed Internet in every cabin, and each room has programmable climate controls. Vibration- and sound-reducing materials were installed in floors, walls and ceilings. The main deck has an open floor plan between the galley and mess.
“The captains on her, without asking, came up to me one day and said, ‘I love the boat,’” Kelly said. “Much of that has to do with the living area.”
“It’s the best design you can find for accommodating four guys,” he added.
Capt. Ryan Riggins and Capt. Clint Campbell have been assigned to command Benson George Moran. Both Campbell and Riggins have offered high praise for the crew accommodations. The performance, they said, has been spot on.
“It’s a really nice tug,” Riggins said. “I like it, what can I say?”