I learned some stuff at the Ocean Star Offshore Oil museum. Let me tell you some of it while you look at this cutaway view of a blowout preventer. If someone says "subsea" (instead of "undersea" or whatever) they're probably in the offshore oil drilling community. In days past, oil platforms had legs down to the ocean floor. That's not always true nowadays--there are some pump/drills underwater that have a pipe up to the surface--where instead of a platform, there's a buoy; a ship called a FPSO goes from buoy to buoy, taking oil. I learned that when the British Safety Council wants to honor you for superior safety practices, they give you a sword; that seems to me like a pretty good sign of confidence in safety-attitude.