I'm not challenging your post so don't take it that way. I've seen many tankers and tugs pulling large barges pass through the rattlesnake just east of where the outside can was marking the eastern end of the Shrewsbury Rocks. So it might not be the HA or BA lanes but it is a lane of some sort used commonly for southerly traffic. Whether that buoy was an official marker or not for shipping lanes I'm not sure, I always assumed that buoy was there to mark the rocks and potential navigating hazard to larger vessels. If not, what was the purpose of that buoy. I'm sure as others have mentioned all large vessels have GPS plotters as did Joseph Hazelwood on the Valdez on that fateful day in 1989 but I would think if a buoy, especially a well lit buoy at night, could act as an added insurance policy that a boat doesn't run aground and create another environmental disaster it would make sense leaving it there. If it was an important marker for all these years, why isn't it now?