[Feature] The Green Side of Petroleum Transport

Last month Crowley Maritime Corporation christened its seventeenth articulated tug-barge (ATB), the Liberty/750-3, at the VT Halter shipyard in Pascagoula, Mississippi. Over the last eleven years the company has spent more than $1 billion building the next generation of petroleum and chemical vessels for its U.S. fleet. “We didn’t invent the ATB,” said Rob Grune, Senior Vice President of Petroleum Services. “But we did make them far safer and more efficient.”

Crowley has been transporting petroleum in the U.S. for well over 100 years, and when OPA 90 became law it was one of the largest Jones Act operators of tugs and petroleum barges. OPA 90 mandated the phase-out of all single-hull bottoms by 2015 and imposed harsh penalties for releasing hydrocarbons into U.S. waters. With the legislation in place, Crowley’s Vessel Management Services team began reviewing the various double-hull alternatives, including ships, integrated tug-barges (ITB) and articulated tug- barge (ATB) technologies.

Choosing the Right Alternative

Building double-hull bottoms for the Jones Act trade is an expensive endeavor, but Crowley’s more than a century of experience provided a wealth of knowledge. The goal was clear: safe operation in the rough environment along the Pacific West Coast.

After ruling out other technologies, Crowley decided to invest in ATBs because the technology deliberately separated the tug and barge units with an Intercon Connection System, which was developed and trademarked by Ocean Tug & Barge Engineering. The Intercon System consists of port and starboard rams installed in a structural support module on the tug. Each ram has a toothed “helmet” at the outboard end that engages a continuous rack of teeth on the barge notch wall, thus establishing a transverse, fixed horizontal axis so the tug can pitch independently of the barge.

“At first there was tremendous pushback from our customers,” Grune said. “But we performed a lot of tests and worked closely with our customers to develop the first ATB. The analysis proved that ATBs were the most viable alternative, especially from a safety standpoint.”

The first ATB unit built consisted of the 550-1 barge, with a capacity of 150,000 barrels, and the Sea Reliance, a 9,280-HP twin-screw tug, which was and still is chartered to Shell. The 550-series was specially designed for weather conditions on the West Coast and can operate at speeds of up to 12 knots in seas as high as Beaufort 5, which means moderate breeze, small waves (1.8 meters) and whitecaps.

Today, the company has four 550-series ATBs in its fleet, and their primary cargoes are clean petroleum products and EZ chemicals. They are also equipped with remote radar gauging for all cargo and ballast tanks and transfer systems that can move 20,000 barrels per hour.

“Soon our clients began saying the 550 ATB technology was great, but can you make them with a larger capacity?” Grune said. “So we built the 650-series to meet the demand.” Crowley built ten 650-series ATBs, which feature improved vessel cargo systems that can easily be modified to transport EZ chemicals such as cyclohexane, paraxylene, and styrene. The 650s can transport 178,000 barrels of product while maintaining safe speeds of up to 12 knots.

“When you first make a trip on an ATB, the ride takes a bit of getting used to because of the vessel articulation with the barge going down and the tug going up,” Grune said. “Otherwise, and from a comfort standpoint, the crews love them. Each crewmember has a private stateroom. The galley is like that on a traditional tug, and there’s TV and Internet access. So going to sea is about as comfortable as it gets.”

Bigger and Better

As Crowley’s two single-hull tankers (the Blue Ridge and Coast Range) were getting ready to be phased out, Marathon Oil began asking what would replace them. “We wanted to transport as much product as the tankers, but there were draft restrictions in Tampa,” Grune explained. “Since ATBs don’t have the weight of the tug attached to the barge, we could load more barrels of product in the Mississippi River to deliver in Tampa. So we built the 750-series.”

The company built three 750 ATBs, which have a capacity of 327,000 barrels. The tugs are 16,320-HP, and the transfer rates are up to 30,000 barrels per hour. In addition to enhanced firefighting capabilities and high-speed mooring systems, the ballast remote control system is able to exchange ballast while underway.

Crowley recently purchased two product tankers, the M/V Pennsylvania and Florida, from Aker Philadelphia shipyard. These Veteran Class petroleum and chemical carriers can transport up to 330,000 barrels. Today, Crowley’s ATB and product tanker fleet make it one of the largest domestic carriers of petroleum products in the U.S.

“One of the best things about Crowley is its diversity,” Grune concluded. “Whether it’s oil transport, salvage, liner services, logistics or naval architecture, we sit with our clients and listen to their needs. Our 17 ATBs are among the safest and most environmentally friendly transport systems on the waters today. And that’s what we mean when we say we provide solutions.” – MarEx