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A Wreck In Depth: The IJN Nagato, Bikini Atoll

Introducing our new monthly series exploring wrecks from Bikini Atoll and Truk Lagoon in depth with this story by Martin Cridge, brought to you by the shipwreck diving specialists at Dirty Dozen Expeditions. Are you ready to make the jump?



By Martin Cridge
Header image of the IJN Nagato and other historical images courtesy of Dirty Dozen Expeditions.

Full Disclosure: Dirty Dozen Expeditions is a sponsor of InDepth.

Admiral Isoroku Yamamoto, Commander in Chief of the Japanese Combined Fleet had been awake since 2 a.m. on his flagship the IJN Nagato, anxiously waiting news on the Japanese attack on Pearl Harbor. Suddenly, the now infamous code word was excitedly shouted down the voice pipe from the radio room. ”Tora Tora Tora!” meaning that surprise had been achieved and the attack was a success. 

Yamamoto with staff onboard Nagato.

Earlier, that same radio room on the Nagato had transmitted coded message number 676, “Niitakayama nobore (Climb Mount Niitaka) 1208” to the Japanese Strike Force (Kido Butai), which was then around 1513 km/940 miles north of Midway and steaming towards Hawaii. Mount Niitaka, located in Taiwan, was the then-highest point in the Japanese Empire, and the message meant that hostilities would commence against the U.S. 

The Nagato was laid down at the Kure Naval Arsenal on August 28,1917, launched just over two years later on November 9, 1919, and commissioned just over a year later on  November 25, 1920. The ship incorporated a number of technological advances for the time, which were developed by the Japanese, and when she entered service she was the world’s largest and fastest battleship. 

The Nagato in its prime.

The Nagato was the first Capital ship in the world to be fitted with 16-inch guns. The eight guns were arranged in four twin-barreled turrets, two forward and two aft. The ship was extensively modified and refitted in the 1930s. The most striking modification was the fitting of a Pagoda mast. Pagoda masts were common on Japanese ships of the time; they had a number of platforms, lookouts, and shelters built upon each other and included watch points, searchlights, rangefinders, gun directors, and spotting points. The end result often resembled a pagoda temple, hence the name. Her displacement also increased at the same time to 39,130 tons and her length to 224 m/734 ft. 

Surviving WWII

The Nagato was the only Japanese battleship to survive the Pacific War. Lack of fuel and materials to repair her meant she saw out the last months of the war as a floating anti-aircraft battery at the Yokosuka Naval Base. The Nagato was purposely taken over by US Navy personnel on August 30, 1945, before the official Japanese surrender was signed on board USS Missouri a few days later. The US Navy said this symbolized the unconditional and complete surrender of the Japanese Navy. After being selected for Operation Crossroads—the atomic tests at Bikini Atoll— preparations were made to get her ready for her final voyage. While no one at that time knew what the outcome of the atomic tests would be, it was always going to be a one-way journey for the once mighty Nagato

The Nagato in very bad shape.

She was in a very bad state of repair, having been seriously damaged before the Japanese Surrender. Patched up, she left Japan on  March 18, 1946, along with the Japanese cruiser Sakawa, which would also be one of Crossroads’ victims. With only two of her four propellers operational, the Nagato could barely manage ten knots. During the voyage, due to previous battle damage and a lack of maintenance, the Nagato started shipping water into her forward compartments. Her pumps couldn’t cope, and stern compartments had to be purposely flooded to maintain the ships stability. Ten days into the voyage the Sakawa broke down and the Nagato attempted to take her in tow, but then the Nagato lost one of her own boilers and, low on fuel, both ships ended up drifting helplessly in the mid-Pacific. To help, two Navy tugboats were dispatched from Eniwetok, and the Nagato was taken in tow by USS Clamp.

The Nagato continued to ship water, developing a seven degree list, meaning she could be towed at only 1 knot. The Nagato finally arrived in Eniwetok on  April 4th, where emergency repairs were carried out and the flooded compartments pumped dry. The repairs enabled Nagato to steam the last 322 km/200 miles to Bikini under her own power and on to her date with destiny. For the Able test of Operation Crossroads, the USS Nevada was the target ship and the Nagato was moored less than 400 m/1312 ft away on her starboard side, well within the expected fatal zone. The Able bomb, however, missed the Nevada, and the Nagato escaped relatively unscathed, suffering only minor damage. For the Baker test the Nagato was once again placed well within the expected fatal zone. 

The Baker test of the “Helen of Bikini” atomic bomb detonated 27m/90 ft underwater on July 25, 1946.

The Nagato, however, rode out the tsunami of water that hit her following the explosion and although she was displaced almost 400 m/1312 ft from her original position, apart from a list to starboard again she appeared relatively unscathed. However, like the other survivors of the Baker blast, the Nagato was now seriously contaminated with radiation. Some minor attempts were made to wash the radiation off her decks, but she wasn’t re-boarded and she gradually settled in the water over the next few days. As the sun set on Bikini on  July 29th, the Nagato was still afloat. Her list was now ten degrees and her stern so low in the water that waves were washing over parts of the main deck, although she didn’t appear to be in imminent danger of sinking. Whatever the future held for the Nagato, she wasn’t leaving Bikini. She had survived the two atomic tests but was now seriously radioactive. Having seen the media fanfare as the USS Saratoga slipped under the waves a few days before, the Nagato decided she would go silently, without fuss, without attention. During the night her stern dipped deeper in the water, she rolled over and settled down on the seabed 52 m/171 ft below. 

Bikini Island. Photo by Martin Cridge.

As the sun crept up behind Bikini Island the following morning, the Americans on Bikini gazed out at the empty spot in the lagoon which the Nagato had occupied the day before. She had gone. 

Diving The Nagato

Diving the Nagato today, it soon becomes evident that everything about this vessel is big, and even after multiple dives, divers can barely scratch the surface of what the Nagato has to offer. Most dives start on the stern as the main mooring on the wreck is attached to one of the four propeller shafts. The first thing that comes into view are the four massive propellers that once drove the Nagato to 25 knots or more. These are now facing towards the surface, and behind them sit two large rudders. 

Nagato’s massive propellers. Photo by Martin Cridge.

Being over 4 m/13 ft in diameter, these are certainly impressive, but most divers quickly bypass these, leaving them for exploration towards the end of the dive. Like most battleships, due to her heavy topside weight, she turned turtle before sinking to the seabed 52 m/171 ft below. It appears the stern hit the seabed first, and the stern section of the ship has now broken away behind the rudders and lies collapsed down on the seabed. 

The once-mighty 16-inch guns haven’t fallen away from their mounts and are still in their turrets in the stowed fore and aft position. The bow guns still have their end caps in place on the muzzle, but the stern guns don’t enable divers to peer down the inside of the barrel. Sitting as they do in 50 m/164 ft, just exploring the aft guns and propellers can take up almost an entire dive. 

Photo by Martin Cridge.

Heading towards the bow from the stern, you eventually come to the huge Pagoda mast. The end of the mast broke away as it hit the seabed and now lies out to the right hand side of the vessel and divers can still see the various upper levels, which included spotting points, rangefinders, and gun directors. Look more closely you can see voice tubes and remains of the lift than ran up inside the mast.

Forward of the Pagoda mast you come to the bow guns. Depending on your dive plan, you might not have much time to explore the bow area, as it’s a 200 m/656 ft swim back to the mooring line. One option is to be dropped on the mid-ships mooring by skiff or do a free descent on the bow—that said, most divers still choose to swim from the stern as there is lots to see on the way and lots of nooks and crannies to explore.

Another option is to take a scooter; needless to say, scootering around the Nagato is a fantastic way to experience the wreck. If decompression starts to build up, one can come onto the top of the upturned hull, which stretches for as far as the eye can see, becoming an artificial seabed. 

Nagoto’s current crew mates. Photo by Jesper Kjoller.

Turtles are often seen on the Nagato as well, and will often swim alongside divers. Due to the lack of human interaction in Bikini, they are far less skittish than turtles found elsewhere. For those who desire it, there are options for penetration both at the stern and bow as well as in the mid-ship sections of the ship. 

Care needs to be taken, however, if one does decide to enter the wreck, as there are many old and discarded lines—some which lead into areas that have since collapsed. Any serious penetrations should be planned properly and with the appropriate temporary lines laid. For most divers, there is enough to see on the outside of the wreck and the Nagato is an often requested repeat dive in Bikini.

Inside one of the cabins. Photo by Martin Cridge.
Aron Arngrimsson old rice cookers deep inside the vessel. Photo by Martin Cridge.

On the way back, observant divers will notice sharks and other sea life coming into the cleaning station halfway back to the mooring. In fact, the Nagato is a good place to see sharks in general. Normally, there are many grey reef and black tip sharks, and occasionally silver tips—and don’t be surprised to be sharing your deco time with a tiger shark or two swimming around you. 

View of the bridge as it sits today. Photo by Aron Arngrimsson.

Additional Resources:


Without Martin Cridge, The Dirty Dozen Expeditions wouldn’t exist. A few years back, Aron and Martin spent a full year diving together in Truk Lagoon. One evening, after a day of demanding dives, they sat, had a beer, and came up with their ideal CCR wreck dive itinerary.

The first-ever Dirty Dozen trip was the result of that beer, and the rest is history. Martin has lived in Truk for eight years with his family and works as the skipper of our expedition vessel in Truk and Bikini.

Martin Cridge. Photo by Aron Arngrimsson.


A Conservator’s Reflections on the Andrea Doria

This month marks the 65th anniversary of the sinking of the SS Andrea Doria, once described as the “Mt. Everest of wreck diving.” Here veteran wreck diver/collector John Moyer, who was granted an “Admiralty Arrest” over the Doria in 1993, in order to recover its famed Guido Gambone ceramic art panels, recounts the key milestones of the deteriorating wreck, and his efforts to display her historical artifacts.




By John Moyer
Header image of the sinking of the Andrea Doria July 27, 1956
, and other photographs courtesy of John Moyer unless noted.

This year marks the 65th anniversary of the sinking of the Italian liner SS Andrea Doria. During the four years the ship sailed between Italy and New York, she was known as a “Floating Art Gallery.” The aftermath of the collision with the Swedish vessel, Stockholm, 80 km/50 miles south of Nantucket Island off the coast of Massachusetts, was described as the greatest sea rescue in history.

The statue of Genoese Admiral Andrea Doria.

Peter Gimbel was the first diver on the wreck on July 27, 1956—the day after it sank—and he returned the following year to photograph it again for Life Magazine. Capt. Dan Turner took a team of divers to the wreck aboard his ship the Top Cat in 1964. Turner blew a hole in the Promenade Deck and recovered the life-sized bronze statue of Admiral Andrea Doria from the First Class Lounge. Unable to free the statue’s base from the deck, they cut it off at the ankles with hacksaws. Four years later, Italian film producer Bruno Vailati led an expedition to survey the wreck and determine if it could be refloated. The Fate of the Andrea Doria(English title) was comprised of footage taken throughout the expedition team’s 21 dives, and the journey inspired Stefano Carletti’s classic book, Andrea Doria-74. 

Gimbel returned to the Doria in 1975 to test his theories on exactly what caused the ship to sink; this research inspired his film, The Mystery of the Andrea Doria. He discovered that the Doria had sustained massive damage to it’s hull when the Stockholm hit. During his next expedition in 1981, Gimbel and his team salvaged the ship’s safe, which he opened later that year on live TV. Various other teams also investigated (or attempted to investigate) the wreck during this time period. Some just explored the sunken vessel, some returned home empty-handed, and some didn’t even make it to the wreck site.

I remember hearing about the Andrea Doria for the first time in 1975 at a shipwreck artifact show in Brielle, New Jersey; the Eastern Divers Association orchestrated the event. I met some divers there who told me about a wreck they described as the “Mt. Everest of Diving.” She was a massive 213 m/699 ft-long passenger liner lying on her starboard side, 74 m/241 ft in the cold, dark North Atlantic. That area of the ocean is known for frequent storms, rough seas, and strong currents. The divers said they often had to pull themselves hand-over-hand down the anchor line, fighting to reach the bottom. Visibility averages about 8 m/26 ft, so they had to be careful not to get hung up in the commercial fishing nets that had snagged the exterior of the wreck. Because she is on her side, it’s easy to become disoriented when penetrating the wreck. The interior is a confusing maze of ceilings that are now walls, walls that are now floors, and stairwells that run sideways. It is filled with silt; the water may be clear when you swim in, but picking up an artifact decimates the visibility, so divers often have to feel their way out. Steel cables and wires hang down, and divers can easily become entangled. When I left that show, I knew I wanted to see the Andrea Doria for myself.

My First Doria Dives 

Moyer’s first dive on the Doria in 1982. Photo by Chuck Zimmaro

In 1982, I dived the wreck for the first time with a small group of divers on a chartered boat. We anchored at the forward end of the Promenade Deck, and I made three dives exploring the area. My first finds were two silver jewelry boxes and a brass-framed window. The next year, we began diving into the ship’s first class dining room where we found piles of china dishes and glassware. In 1985, a dive team and I spent a week on the wreck and recovered the 68 kg/150 lb brass bell from the ship’s aft steering station.

After that 1985 trip, I began my serious research into the ship and collected everything I could find related to the Andrea Doria. I traveled to Italy to meet with the engineers at Ansaldo Shipyard—who had designed the ship—and the Italia Line officers who were onboard the night of the collision. I also corresponded with Bruno Vailati to get his insight into diving on the wreck. Between 1985 and 1991, we made many trips out to the site, exploring new areas of the wreck and recovering any artifacts we found.

In 1992, based on information I had received from Italy, Billy Deans and I began searching the bow of the wreck for the ship’s main bell. We entered through a hatch, swam along a corridor, then up a hallway to the room where I was told it was stored. When I pried opened the door, I found the room was filled with about 1 m/3 ft of silt and debris. Later that year, I took a team of 15 divers and crew aboard the R/V Wahoo and spent a week cleaning out the room with an airlift. Unfortunately, we did not find the bell.           

John Moyer and Capt. Billy Deans preparing to dive the Doria

During the winter of 1992-1993, Rinaldo Negri, who had helped design the Andrea Doria, sent me a book with a photo of the ship’s Wintergarden Lounge; the photo captured the lounge’s large wall panels inlaid with ceramic sculptures created by Italian artist Guido Gambone. I was able to match that photo with the ship’s plans and determine exactly where the works of art were on the ship. Billy Deans and I dove into the Wintergarden and found that two panels had fallen from their mountings and were lying deep inside the wreck. Later that summer, I returned on the R/V Wahoo, this time with a team of 20 divers and crew, to recover the panels. Over a period of four days, working in near zero visibility at a depth of 61 m/199 ft, the team rigged each 454 kg/1,000 lb panel  with inflatable lift bags and floated them to the surface.  

Recovering the Gambone ceramic panels. Photo by Bill Campbell
Moyer with the restored Gambone panels . Photo by Steve Gatto.

Prior to the expedition, my attorney filed legal papers in the US District Court in Camden, New Jersey. Judge Joseph Rodriquez granted an Admiralty Arrest, asserting the court’s jurisdiction over the Doria, and appointed me custodian of the wreck. I was required to attach the signed arrest papers (inside a sealed container) to the wreck. Later that year, we again appeared before Judge Rodriquez. We argued that, although insured by an Italian consortium, the underwriters had made no attempt at salvage in nearly 40 years; therefore, they had abandoned the wreck. The court agreed and named me Salvor-in-Possession. This gave me exclusive salvage rights, clear title, and ownership of anything we recovered. I did not want to shut the wreck down from recreational divers and have allowed them to continue to dive it, to photograph, and to recover small artifacts. In his ruling, the Judge stated: “Moyer’s independent research and archeological documentation of salvage efforts indicate a respect for the Andrea Doria as something more than just a commercial salvage project.”  

Warrant of Arrest for the Doria.

Displaying The Doria

From the very beginning, my intention was to collect certain artifacts from the wreck and as many items related to the ship that I could find. I wanted to create an Andrea Doria exhibit to tell the story of what some call the most beautiful ship to ever sail. I have put on dozens of temporary exhibits and displays over the years and hope someday to have a large permanent exhibit. The general public has always been very interested and pleased to see what we have recovered. I am also working closely with Andrea Doria survivor Pierette Simpson. She is the author of Alive On The Andrea Doria and produced the award winning film Andrea Doria: Are the Passengers Saved?

We have held many events, participated in film screenings together, and have ridden in the New York City Columbus Day Parade (along with other survivors and Ted Hess, lead diver of Gimbel’s 1981 expedition). At the end of the parade, there was a ceremony where Pierette rang the Andrea Doria bell in memory of the souls who lost their lives in the sinking. We are currently working with The Noble Maritime Collection in Staten Island, New York on an exhibition which will open late spring 2022.

The inevitable decay of sunken ships is slow and most often unobserved.  The sinking of the Andrea Doria produced a wreck of very unusual characteristics. Due to newsreel camera planes circling overhead, it became world famous, and its final resting place is accessible to divers. When Peter Gimbel first visited the wreck in 1956, he saw no obvious damage to the ship. Since then, divers have been reporting major decay events on the wreck. The wheelhouse was still intact when the Italian dive team filmed it in 1968, but it was gone by 1973. The funnel, mast, and top three decks of the superstructure had fallen off by the time I first dove it in 1982. We used the port side bridge wing as a landmark until it fell off sometime in the early 1990s. The Wintergarden was completely intact when we recovered the Gambone sculptures in 1993, but it totally collapsed only two years later.

John Moyer and Gary Gentile recovered the statue base in 1996

Later in the 1990s, we noted cracks in the hull and the Boat Deck, Upper Deck, and Foyer Deck had started to slide downward to the sea floor. A recent multibeam sonar scan by the University of New Hampshire showed that the cracks have expanded and that the hull has entered its final stage of the flattening process.   

Someday the Andrea Doria will be an unrecognizable pile of debris on the bottom of the sea. Fortunately, we have been able to rescue many historically important artifacts and unique works of art before they were lost forever.

Additional resources

InDepth: Stefano Carletti: The Man Who Immortalized The Wreck of the Andrea Doria By Andrea Murdock Alpini

Alert Diver: Remembering the Andrea Doria by Michael menduno

Diver: Doria Tipped The Scales by Michael Menduno

John Moyer’s first dives were in 1970, and he began diving on shipwrecks in 1975.  He has made thousands of dives on wrecks in the US, Canada, Great Britain, Mexico, and the Caribbean. He has dived on the liner RMS Empress Of Ireland, Ironclad Monitor, Light Cruiser USS Wilkes-Barre, and was one of the first Americans to dive on the WW1 German fleet in Scapa Flow, Scotland.  

He has a degree in Biology from Stockton University, a USCG 100 Ton Master License, and worked as an Instructor at the Dive Shop of New Jersey and Key West Divers.  Moyer is a member of the Atlantic Wreck Divers Dive Club and is the recipient of the prestigious Pioneer of Northeast Diving Award. He has appeared on the History Channel, A&E Network, and Dateline NBC. He is co-author of “The Decay of the Andrea Doria,” published by the Society of Naval Architects and Marine Engineers, and he appears in the docufilm Andrea Doria: Are the Passengers Saved?

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