I have no idea. Maybe they're afraid of a spill? Maybe it's the height of platforms to be obscured by the horizon. Somewhere I read 25 miles is the limit for being obscured by the horizon because of the earth's curvature, but the height of a vessel or structure has to come into play. Maybe that was before supertankers?
Off the coast of LA the limit is down to a few hundred yards...they just make the rigs ‘look pretty’!!! if it’s good enough for California it’s good enough for florida! We’re talking GAS here folks...when was the last time you heard of a ‘gas spill’!!!