While not dismissing the destructive
power of winds and seas, the USCG report referred to in the link provided by the original poster says that the buoy is thought to have run aground on a bank soon after it broke loose.....
Then just imagine the whole thing being rolled over and over by breaking waves and the destruction becomes quite understandable.
The sand is probably what scoured most of the
paint off as well.
Have fun
Flying Dutchman