Fabricating tight ships on a tight deadline

Cleveland shipyard ramps up aluminum welding capabilities

THE FABRICATOR® FEBRUARY 2012

February 1, 2012

For Great Lakes Shipyard, a division of the Great Lakes Towing Co., located on the Cuyahoga River’s Old River Channel just off of Lake Erie, one order posed the ship designer and fabricator’s biggest challenge in recent history: designing and fabricating not one but two aluminum ships, something the company had yet to do.

Fabricating tight ships on a tight deadline - TheFabricator.com

Figure 1: Welders at Great Lakes Shipyard used a pulsed, inverter-based power source and solid aluminum wire to weld the aluminum hull.

When the U.S. Geological Survey (USGS) approached Great Lakes Shipyard in Cleveland in June 2010, the government research agency had a tall order: To build two 70-foot aluminum vessels for delivery before September 2011.

For the USGS, the $8.2 million contract meant the agency would finally replace two of its oldest research vessels in its Great Lakes fleet with “floating laboratories” equipped with instrumentation designed to improve the understanding of deepwater ecosystems and fish species in Lake Erie and Lake Ontario. The USGS, which is funding the new construction through the American Recovery and Reinvestment Act, will moor one ship at the USGS Lake Erie Biological Station in Sandusky, Ohio, and the other at its Lake Ontario Biological Station in Oswego, N.Y.

For Great Lakes Shipyard, a division of the Great Lakes Towing Co. located on the Cuyahoga River’s Old River Channel just off of Lake Erie, the order posed the ship designer and fabricator’s biggest challenge in recent history: designing and fabricating not one but two aluminum ships, something the company had yet to do.

“The Towing Company”

Most in the region’s marine business know The Great Lakes group of companies as simply “The Towing Company,” as if there were no other. That’s understandable, considering its numerous green and red tugboats have served the ports of the Great Lakes for more than a century.

What’s less well-known, though, is the company’s diversity and long history, which includes Standard Oil’s John D. Rockefeller, Western Union’s Jeptha H. Wade, and the other founding shareholders who incorporated the company in 1899. The shipyard has called Cleveland home ever since, first operating in the Flats District until the 1957 great Cuyahoga River fire, when it moved to its present site. In 1983 the company entered the commercial ship repair business, but its scope was limited by the facility’s small size and its 250-ton drydock.

In the years since, the company has evolved into a diversified marine service organization. It even has ventured into the near- and offshore wind sector, partnering with Case Western Reserve University to develop offshore floating platforms. The group consists of companies like Tugz International, Admiral Towing & Barge Co., Soo Line Handling Services, and others that provide a variety of services, from line handling at locks operated by the U.S. Army Corps of Engineers to marine transportation around the islands of the Caribbean.

Back in Cleveland, the organization now owns 7.26 acres, environmentally improving land formerly classified as a Superfund site. The yard has a 770-ton-capacity (yes, tons) mobile vessel hoist—the largest on the Great Lakes and second largest in the Western Hemisphere. The final phase of the shipyard expansion, slated for completion by 2014, will include an additional 67,000-square-foot, 72-ft.-high facility for year-round shipbuilding.

The shipyard expansion has been good for the Cleveland economy. The yard employs more than 80 people full-time, many of whom make wages far above average for the area, according to a company briefing paper. A good portion of Great Lakes’ employees perform jobs requiring highly developed skills, including the welding team that last year successfully completed two aluminum vessels for the USGS. Typically, it takes about one year to design a ship of this size and another year to fabricate it. The USGS order required Great Lakes to design and build two ships of this magnitude in just over a year (see Figure 1).

Working With Aluminum

The agency, which approached Great Lakes with basic preliminary designs, chose to build the two vessels with 5083 aluminum alloy after performing a feasibility study, said Christopher Peifer, Great Lakes assistant vice president of engineering and the company’s safety officer.

“The three biggest factors that drove them to choosing aluminum were draft, speed, and weight,” he explained. “Lake Erie is the shallowest of all the Great Lakes, and minimizing the vessel’s draft is crucial for access to certain regions. The speed allows the owner to reduce transit time between sampling locations, and the weight determines where the vessel can be pulled out of the water for the winter months.

“The aluminum was a big change for us. We had worked with it a bit on smaller jobs, but we had not built an entire boat from it,” Peifer said. “But we were up to the challenge of learning the ropes while we worked on such a tight turnaround.”

Design Considerations

To build these vessels, Peifer and other on-site engineers received preliminary 3-D drawings from the USGS and then turned these drawings into 2-D layouts that indicated all materials and plate sizes. Each part in the layout was assigned a piece number and was sent to the material provider, who then cut the pieces and sent them back to the shipyard with a set of assembly drawings.

“We used those assembly drawings to tack the pieces together and weld it out from bow to stern,” said Joseph Craine, shipyard general manager. “Actually, we do more than just weld it out. We do all of the ancillary work as well, including electrical, piping, insulation, and more. It’s a turnkey process.”

On top of this, the company fit both 70-ft. aluminum structures in its 10,500-sq.-ft. fabrication facility. This meant that both ships could be welded under cover at the same time (see Figure 2).

Ramping up to Weld Aluminum

Great Lakes’ welders had to adapt to the subtleties of joining aluminum with gas metal arc welding (GMAW) using solid aluminum wire. And, of course, this was shipyard work, which meant a lot of out-of-position welding, including vertical-up and overhead (see Figure 3). They also needed to learn to work with a new, inverter-based, pulsing power source, Power Wave®, which Great Lakes acquired for the project from The Lincoln Electric Co., Cleveland.

“The crew was used to welding in position with older power sources using cored wire,” said Ryan Cooper, Lincoln’s technical sales representative. “To get the out-of-position weld on aluminum, they needed to learn how to use a pulsing power source to get a good bead and the penetration needed for this kind of job.” Cooper, along with an instructor from the Lincoln Electric Welding School, spent two weeks with the crew to get them up to speed on the new process.

As Craine noted, only a handful of the welding staff was certified in aluminum welding by the American Bureau of Shipping, the agency whose welding standards the shipyard follows. “Only three or four of our 28 welders were certified to weld on aluminum,” he said. “We knew we had our work cut out for us.

“Aluminum is much more difficult to work with than steel,” Craine continued. “It moves around, warps, flexes. There’s less margin for error. Because it is delicate and also oxidizes quickly, you can’t grind a weld out on it like you can with steel. You have to start over with a fresh component. And in steel fabrication, once you cut it, you can just tack it and weld it. With aluminum, you have to clean it and then weld it almost immediately after cutting.”

Once training was complete, the fabrication crew got to work. During testing, the 5083 aluminum—a high-tensile-strength alloy—often broke, but the welds—made with solid aluminum wire (Lincoln’s SuperGlaze®)—didn’t. In other words, the ship fabrication passed muster.

To keep pace with the requirements of both the materials and the job deadlines, the Great Lakes fabrication team worked 10-hour shifts, six days a week on both vessels. Workers welded overhead, vertical, standing on ladders, crouched, and in every position in between. Obviously, the shipyard’s welding team learned a thing or two about some specialized out-of-position welding.

Ultimately, they helped the company do what it had never done before: deliver two large aluminum vessels in a little more than a year.

Photos provided by The Lincoln Electric Co., Cleveland.



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