After completing a series of rigs designed for warm water, Vicksburg’s LeTourneau oil rig-building yard has begun a new series for deeper water and harsher conditions.

LeTourneau’s Vicksburg Marine yard officially began construction Friday on a class of equipment that can drill in water up to 400 feet deep and can be used in colder environments such as water off Canada or the British Isles.

&#8220It’s quite a bit bigger,” LeTourneau’s vice president here, Mike Gray, said of the new class, called 240C, compared with its predecessor, called Tarzan.

The last of three Tarzan rigs to be built here was completed in May. A fourth is to be completed at one of LeTourneau’s other locations. Tarzan rigs drill in water 350 feet or shallower.

Once they reach the water’s floor, both the 240C and Tarzan classes can drill to the same depth, 40,000 feet, Gray said.

The 240C, which has yet to be given a name, is due for delivery in the second quarter of 2008, Gray said. Construction of at least one other 240C is to follow here, Gray added.

When complete, its base is to measure 220 feet by 228 feet, Gray said.

The start of its construction was marked Friday with a brief keel-laying ceremony attended by about 15 people at the yard. A 60-foot-by-30-foot steel piece of the hull was moved by a crane onto a row of beams and workers immediately began aligning it for attachment.

LeTourneau is a division of the Rowan Companies of Houston, Texas. Rowan also retains and operates many of the rigs it builds.

In addition to the 240C begun Friday LeTourneau is working on a single-rig series of a class called Super Enhanced 116 for a customer called Berfordora, Gray said.

LeTourneau is one of Vicksburg’s largest employers, with about 1,100 workers, Gray said. Vicksburg Marine began as a munitions plant during World War II and has evolved into a global center for manufacturing movable oil rigs.

&#8220We’re going to continue to grow,” Gray added.