The City of Washington was an iron-hulled steamship launched on August 31, 1877. It now rests in 32 feet of water on the north end of the Elbow Reef barrier reef system east of Key Largo. The wreck is a popular dive site in the Florida Keys and is part of the Florida Keys National Marine Sanctuary Shipwreck Trail.

Article Summary

• The Thunderbolt is a 188-foot long shipwreck located off Marathon in the Florida Keys, sunk intentionally as an artificial reef on March 3, 1986.
• Originally named Randolph, it was built in 1942 as a mine planter for the U.S. Army, later transferred to the Navy, and eventually used by Florida Power and Light for research on electrical energy from lightning strikes.
• The wreck sits upright in about 120 feet of water, with its observation deck at 75 feet depth.
• It’s known for its intact structure, colorful marine growth, and abundant sea life including angelfish, barracuda, and goliath groupers.
• Notable features include a giant cable spool on the bow, an accessible wheelhouse, and exposed engine room.
• The Thunderbolt is part of the Florida Keys Wreck Trek program for advanced divers.
• It’s considered an easily navigable wreck that can be explored in a single dive, offering unique photo opportunities and swim-throughs.

Shipwreck Thunderbolt Florida Location Coordinates and Depth

Depth

The wreck lies intact and upright on a sand bottom at a depth ranging from 85 to 120 feet. The top of the observation deck is at 75 feet, while the rudder and propellers are at the maximum depth of 120 feet.

Location

The Thunderbolt shipwreck is located at GPS coordinates 24°39.480’N 80°57.90’W, approximately 4 miles south of Marathon and Key Colony Beach in the Florida Keys.

What to Scuba Divers Say About This Ship

• Easily Navigable: The wreck is easily navigable, and divers can see it in its entirety during one dive.
• Colorful Marine Life: The wreck is encrusted with colorful soft corals and sponges, and is home to a variety of marine life including large angelfish, barracuda, and goliath groupers.
• Memorable Photo Ops: The giant cable spool on the bow makes a memorable spot for photo opportunities.
• Intriguing Swim-throughs: The wheelhouse is an easy and intriguing swim-through, and the aft end of the wreck has been cut away to expose the engine room.
• Well-Preserved: The wreck is well-preserved and sits upright and intact, making it a fascinating site to explore both inside and out.
• Year-Round Diving: The wreck is accessible year-round, with schools of amberjack and migrating tarpon in the summer, and 700-pound goliath grouper and five-foot black grouper present year-round.
• Dive Time: While the wreck is at a depth of 120 feet, divers can expect 20 to 30 minutes of bottom time with computers.
• Part of the Florida Keys Wreck Trek: The Thunderbolt is part of the Florida Keys Wreck Trek program, which provides advanced- and wreck-certified divers with a special dive log book to preserve their experiences diving on the nine submerged vessels.

What Kind of Marine Life Can Be Found on The Ship

The Thunderbolt shipwreck is home to a diverse array of marine life:

• The wreck is encrusted with colorful soft corals and sponges.
• Large angelfish, barracuda, and goliath groupers are commonly seen around the wreck.
• Schools of amberjack and migrating tarpon can be spotted in the summer months.
• Five-foot black grouper and 700-pound goliath grouper are present year-round.
• Tomtate grunts and other reef fish now reside on the wreck, which has become a mature, photogenic artificial reef.

Key Information

What Makes The Thunderbolt a Unique Diving Experience

1. Intact Structure: The Thunderbolt sits upright and intact on the seafloor, providing an immersive experience for divers to explore its entire length in a single dive.
2. Colorful Marine Life: The wreck is encrusted with colorful soft corals and sponges, and is home to a variety of marine life including large angelfish, barracuda, and goliath groupers.
3. Easy Navigation: The wreck has been prepared for divers with wide swim-throughs, making it relatively easy to navigate despite its depth.
4. Historical Significance: The Thunderbolt has a rich history, originally built as a mine planter during World War II and later used for research on electrical energy from lightning strikes.
5. Part of the Florida Keys Wreck Trek: The Thunderbolt is part of the Florida Keys Wreck Trek program, which provides advanced- and wreck-certified divers with a special dive log book to preserve their experiences diving on the nine submerged vessels.
6. Accessible: The wreck is located in approximately 120 feet of water, making it accessible to advanced scuba divers with the necessary certification and experience.
7. Unique Features: The Thunderbolt has several interesting structural features, including a giant cable spool on the bow, twin propellers, and an anchor chain extending west off the port side.
8. Pelagic Encounters: The wreck attracts large pelagic fish like amberjacks and tarpon, and even occasional sightings of great white sharks.

What is The Full History of This Ship

The Thunderbolt, originally named Randolph, was built in 1942 by Marietta Manufacturing Company in West Virginia under contract to the U.S. Army during World War II. It was one of 16 sister ships launched on June 2, 1942 to plant and tend defensive coastal minefields for the Army’s Coast Artillery Corps.

In 1949, the Randolph’s minelaying function was transferred to the U.S. Navy, but it was never commissioned and remained in the Naval Reserve Fleet, first in South Carolina and then in Florida. Caribbean Enterprises of Miami purchased the vessel in 1961, and later Florida Power and Light bought it for research on electrical energy from lightning strikes, renaming it Thunderbolt.

Eventually, Florida Power and Light donated the Thunderbolt to the Florida Keys Artificial Reef Association. On March 3, 1986, the 189-foot long ship was intentionally sunk as an artificial reef in approximately 120 feet of water four miles south of Marathon and Key Colony Beach. Prior to being scuttled, the Thunderbolt was stripped of all but a few major pieces of equipment.

Today, the Thunderbolt sits upright and intact on a sand bottom, with its observation deck at 75 feet and propellers at 120 feet. It is encrusted with colorful soft corals and sponges and is home to a variety of marine life including large angelfish, barracuda, and goliath groupers. The wreck is part of the Florida Keys National Marine Sanctuary Shipwreck Trail and is one of the most popular dive sites in the Marathon area.

What Historical Features Can Still Be Identified on The Thunderbolt Wreck

• The Thunderbolt’s hull is 189 feet long with a forecastle, which served as the cable handling area, and has a cruiser stern.
• A horizontal cable handling reel, which was used for laying mines during the ship’s military service, lies at 80 feet and is centered on the after-end of the forecastle deck.
• The remains of the ship’s superstructure, including the observation deck located at 75 feet, are still visible.
• The aft-end of the superstructure has been cut away, exposing the interior of the hull at the engineering space.
• The rudder and propellers, which lie at 120 feet, remain intact to complement the stern section of the hull.

What Safety Measures Are in Place for Divers Visiting the Thunderbolt Wreck

1. Depth and Certification Requirements: The Thunderbolt lies at a maximum depth of 120 feet, so an advanced open water certification is advised. Divers must be experienced and properly trained for the depth.
2. Mooring Line: A mooring line is typically used to descend to the wreck. However, the mooring has been off the wreck for several months, and there are no immediate plans to restore it. Dive operators may need to use alternative methods like a shot line to mark the wreck’s location.
3. Dive Planning and Briefing: Dive operators provide detailed briefings on the wreck site, including its history, layout, and potential hazards. They also help plan the dive to ensure that divers are prepared and equipped for the conditions they will encounter.
4. Guided Dives: Many dive operators offer guided dives to the Thunderbolt wreck.These guides are experienced and knowledgeable about the wreck and can help ensure a safe and enjoyable dive experience.
5. Dive Time: Divers can expect 20 to 30 minutes of bottom time on the Thunderbolt due to the depth. Proper decompression stops and safety stops are essential.
6. Buoyancy Control: Mastering buoyancy control is critical to avoid damaging the wreck and marine life. Divers should be able to maintain a stable position in the water column.
7. Respect for Marine Life: Divers must be aware of and avoid disturbing the abundant marine life on the wreck, including large predators like goliath groupers.

Dive Shops That Prove Diving Trips to This Shipwreck

1. Captain Hook’s Marina and Dive Center

• Located in Marathon, FL
• Offers Thunderbolt wreck dive trips as part of their regular dive schedule
• Requires a minimum of 3 divers for the trip

2. A Deep Blue Scuba Diving & Snorkeling Center

• Located in Marathon, FL
• Provides guided dives to the Thunderbolt and other wrecks in the area

3. Tilden’s Scuba Center

• Located in Marathon, FL
• Runs dive trips to the Thunderbolt and other popular sites in the Middle Keys

4. Captain Hook’s Big Pine Key

• Located in Big Pine Key, FL
• Offers Thunderbolt wreck dives as part of their dive schedule

5. Key Dives

• Located in Islamorada, FL
• Provides access to the Thunderbolt and other wrecks in the Florida Keys

6. Florida Keys Dive Center

• Located in Islamorada, FL
• Offers guided dives to the Thunderbolt and other notable wrecks

The Keys Wrecks

• USS Duane
• USS Spiegel Grove
• Thunderbolt
• City of Washington
• SS Benwood
• USNS Vandenberg
• Joes Tug
• Cayman Salvage Master