ALGOR FEA Helps Shipbuilder Hoist 1,000 Tons

By DE Editors

Section of ship hull displacement magnitude.

North American Shipbuilding (NAS; Larose, LA) designs and constructs offshore vessels for its parent company, Edison Chouest Offshore (ECO), and affiliated companies. As part of its ship-building and repairing operations, NAS uses finite element analysis (FEA) software from ALGOR, Inc. (Pittsburgh, PA).

NAS crane-lifted this 1,000-ton superstructure as part of the assembly process for a new anchor-handling tug supply ship. Engineers at NAS used ALGOR FEA software to analyze key components to verify that the ship could withstand the lifting operation.

ALGOR FEA is used at NAS by engineers.

For the 1,000-ton crane lift, Gary Rook, Technical Manager of NAS, explained, “The ship was designed to support oil exploration in the oceans of the world. The hull was built in a fabrication building and then rolled onto a launching dock and floated into the water. A superstructure was built separately from the hull due to weight limitation on the dock. Then, the superstructure was lifted onto the hull for installation.”

The ALGOR analyses to simulate the lift were performed “early on during the design” of the ship. Two key components –  the port side frame and a section of the hull – were analyzed because they contained the pad eyes and saddles where the cranes would pull upward on the superstructure. Hence, these components would experience the greatest stresses.

Similarly, a section of the hull was modeled with two lifting forces of 350,000 lbs applied at each of two pad eyes for a total lifting load of 700,000 lbs (or 350 tons), representing 35 percent of the total lift load. The ship is currently in successful operation.

when exposed to prolonged and redundant forces.”

For more information, contact ALGOR.

Sources: Press materials received from the company and additional information gleaned from the company’s website.