The U.S. Coast Guard and the Bureau of Safety and Environmental Enforcement (BSEE) has issued a Joint Safety Alert after a dynamic positioning (DP) failure resulted in an offshore service vessel losing its position while conducting a critical outer continental shelf (OCS) activity. The vessel was performing overdue maintenance on its main power distribution bus circuit breakers at the time. The failure potential had not been noted in the vessel’s safety management system (SMS) or the leaseholder’s safety and environmental management system (SEMS).  
http://www.uscg.mil/hq/cg5/cg545/alerts/0814.pdf