Aging fleets and new safety requirements are sparking a boom in orders for deep-sea drilling rigs and related equipment, boosting the profits of companies such as National Oilwell Varco (NYSE:NOV) and Cameron (NYSE:CAM) that make the equipment. Just yesterday (I, II), Transocean (NYSE:RIG) and Rowan (NYSE:RDC) made arrangements for new rigs to be equipped with dual blowout preventers.