aue-mike:The GPS numbers, along with the history of the USCG BLACKTHORN (and pictures of it) can be found in the book, Shipwrecks of the Sunshine State.
As mentioned, the large yellow Pinellas County Artificial Reef Program buoy is not on the BLACKTHORN, but is just off the bow of the SHERIDAN. If you swim off the bow of the SHERIDAN, you will intersect the wreck of the BLACKTHORN. The stern is broken off, but fairly intact, and the main hull is laying on its side.
There is also a barge just off the stern of the BLACKTHORN. It is possible to swim all of these wrecks on one dive. Again, all the numbers (for all three of these wrecks, and over 1,000 more) are in the aforementioned book.
Cheers,
Mike
Was just at the LDS looking for a pressure guage and decided to buy the book. That was before reading your post!
Was reading it in the waiting room at the docs office, and now I am home and will be reading it some more.
Good job on the detail in that book.