The Coast Guard found serious safety & environmental violations on 'Noble Discoverer' used in Arctic waters off Alaska. The Coast Guard found 16 violations on the Noble Discoverer, one of Shell’s two drilling rigs for Alaska’s Arctic waters. The company’s other rig, the Kulluk, has its own troubles, reports the Anchorage Daily News. The Noble Discoverer is a converted log carrier owned and operated by Noble Corp. for Shell’s Arctic efforts. The 514-foot-long rig was built in 1966 and converted into a drilling ship 10 years later. It has been upgraded and refurbished to work in the Arctic at a cost of $193 million. The vessel dragged its anchor and nearly grounded in Dutch Harbor, Alaska, before the start of its drilling work.