Dives off Marathon
This wreck was sunk intentionally in the mid 1980's to become an artificial reef, and sits in 120 of water. This wreck is a good one if you like to enter the ships and poke around inside. The whole thing is open, so it is safer than many of the artificial reef wrecks which have either turned over onto their sides since being scuttled, or weren't made to be entered by divers. The Thunderbolt has entrances at the wheelhouse and on the main deck. You can swim all around inside, including up a flight of stairs. The engines of the ship were housed in a gigantic space, which is also fun to swim around in, to explore the cavernous space.
The original name of The Thunderbolt was U.S.S. Randolph, and was built in 1942 for the Army. It's 188 feet long and after if left its army career during which is lay lots of underwater cable, it was sold to the Florida Power and Light Company. They used it as a lightning research vessel, hence the new name. You can still see the cable-laying spool if you dive down there. There's an underwater buoy, which, if you clip yourself to it, provides an anchor from which you can follow a steel cable into the ship and look around. Advanced divers only.
The Thunderbolt is found 5 nautical miles off the shores of Marathon, FL, which is in the Middle Keys, and the depth ranges from 75 to 120 feet. Visibility is around 30 to 70 feet and the current can be strong. Advanced divers only!