This 188-foot military ship is the jewel of the Marathon wreck fleet. Sunk intentionally as a dive attraction in March 1986, she now sits perfectly upright in 115 feet (35 m) of water offering 45 feet (14 m) of relief. Originally named the USS Randolph, she was built for the U.S. Army as a cable laying boat. She later served FP&L as a research ship to attract and study lightning, hence her name "Thunderbolt". After sinking at the dock in Miami, she was later purchased by a group of Keys divers in 1986, prepped as an artificial reef, and scuttled for her destiny as an artificial reef.

Her superstructure is now coated with colorful sponge, coral, and hydroid, providing refuge and sustenance to large angelfish, jacks, and a variety of deep-water pelagic creatures. Divers will want to investigate the huge twin propellers and descend into the engine compartment beneath large arches in the main deck. Her bow is dominated by a huge horizontal cable reel. Dropping over the stern of the vessel divers can examine huge twin props. Large hatches off the main deck open into the engine compartments where it is possible to descend into the hull to 110 feet (34 m).

This unique card provides detailed depiction of Thunderbolt wreck near Marathon, Florida. Each waterproof card is printed on both sides, made of durable PVC plastic and is designed to be taken on the dive. They are also three hole punched to fit in standard log books.