From the World War I Centennial News Podcast

Remembering Veterans:
Dr. Alexis Catsambis on the Mystery of the USS San Diego 

In April 19th's edition of the World War I Centennial News Podcast, Episode 119, Dr. Alexis Catsambis of the US Naval Heritage and History Command spoke with host Theo Mayer about the sinking of the USS San Diego, and the process of unraveling the mystery behind what went wrong. The following is a transcript of the interview, edited for clarity:

Theo Mayer: Next, for Remembering Veterans, we're going to explore the story of a ship that sank on the eastern seaboard in July of 1918. Now, first commissioned in 1907 as the USS California, the cruiser was rechristened the USS San Diego on September 1st, 1914. Now, she spent most of her career as part of the Pacific fleet, before being reassigned to the Atlantic fleet on July 18th, 1917, where she escorted convoys on the first part of their journey to Europe. Although other ships like The USS Tampa were also lost in World War I, this event was shrouded in mystery and there were many theories about why and how the San Diego went down. That is until last year. With us to talk about this is Dr. Alexis Catsambis, a maritime archaeologist with the Underwater Archaeology Branch of the U.S. Naval History and Heritage Command in Washington D.C. Since 2008, Dr. Catsambis has provided for the stewardship, research, conservation and curation of submerge the US Navy heritage sites, including the San Diego. Dr Catsambis, thank you for joining us.

Dr. Alexis C.: A pleasure. Thank you for having me.

Dr. Alexis Catsambis is a maritime archaeologist with the US Naval History and Heritage CommandTheo Mayer: Let me start with underwater archaeology in general. How would you define the field and its challenges?

Dr. Alexis C.: Underwater archaeology uses scientific methods in an underwater environment, to study and interpret the remains of the human past.

Theo Mayer: Now, about the San Diego, herself. What was the news at the time? What was she doing when she went down?

Dr. Alexis C.: Well, many Americans, when they think of the Great War, they envision the carnage of trench warfare in lands across the ocean. The sea itself actually played a defining role in the outcome of the war. The Germans were able to sink, through their U-boats, several hundred merchant vessels, and laid close to 45,000 mines or so. They got very close to choking Britain off from critical supplies. That is until the United States entered the war in April 1917. Within a month or so, the first 14,000 troops had landed in France. A year later in the summer of 1918, that number was closer to 10,000 troops a day. What made this incredible transfer of up to 2 million or so soldiers to France, combined with the British Royal Navy and the US Navy, was the convoy system. The USS San Diego, having served in the Pacific Fleet, during the course of the war was placed in the convoy system. And in fact, she was making her way from New Hampshire, where she had just been resupplied with coal to make the crossing of the Atlantic, to New York. Then on a tragic day, on the 19th of July 1918 a single explosion rocked her hall, and just over 20 minutes later she had capsized on the surface and sunk.

The USS San Diego, c. 1916Theo Mayer: Okay, there were lives lost, but the loss of life was really limited, wasn't it?

Dr. Alexis C.: There were over 1100 men aboard San Diego. We've been able to find that the captain delayed issuing the abandon ship order for about 10 or 11 minutes, in order to not to make his ship an easy target for any German submarine that surfaced. Then, within the span of three or four minutes, the ship had turned on it's beams, essentially. The captain jumped off one side, as the last man, and had just been proceeded by his executive officer who jumped off the other side. Six men lost their lives in the attack, and the abandoning ship maneuvers that followed. That is a tremendous testament to the response, as well as the preparations of the crew of San Diego, for the eventuality that they would receive an enemy attack.

Theo Mayer: It really is. Now, when the archaeology project to study her was initiated, how was it conducted? How did it come about?

Dr. Alexis C.: Naval History and Heritage Command is responsible for the management of the Navy's sunken military craft. That includes ships and aircraft, from the American Revolution onto the current day and the Underwater Archaeology Branch is specifically responsible for researching, interpreting, and protecting these sites. The project with San Diego aimed to both document and assess the condition of the ship, with the 100th anniversary of its sinking in view, to determine if we could the identify the cause and the circumstances of the vessel sinking. We wanted the project to serve as a training mission, and they used advanced data collection and analysis. And we wanted to commemorate through this project the Navy's role in World War I, and of course the loss of the six men on San Diego.

Theo Mayer: Now, you actually concluded some stuff. What led to the evidence that the ship had actually been sunk by enemy action?

Dr. Alexis C.: There was generally an understanding, that the ship had been sunk by the enemy. But it was unclear whether that had transpired through an act of sabotage, a torpedo, or a mine. The single explosion was very effective, and we've concluded that that's actually because of the circumstances of the sinking itself, rather than the size of the explosive. But it did not lead to a clear conclusion at the time, as to what sank the ship. Over the decades that followed, a number of theories were posited, and ultimately through this project we've been able to conclude that an internal explosion, in the form sabotage for example, would have been highly unlikely. This is based on historical record, and modeling of the explosion itself. We have engaged a number of partners in this effort, including the Naval Surface Warfare Center at Carter Rock, and they specialize in such modeling of impacts. They also contributed to the modeling of the flooding of the ship. Which has given us further insight, and really suggested that there's no evidence to support a torpedo attack either. That's due to the size of the charge of a German torpedo at the time versus the size of the mine. Then to complement that, the historical record provides us with the types of mines that the German submarines would have used at the time. One, as potentially having been on board U-156, the particular German submarine we've come to conclude struck San Diego.

Theo Mayer: That's really interesting. It's not just physical observation, but it's forensic record evidence, that tells the story. How has all this sleuthing allowed you to conclude, specifically what happened? Are you satisfied, or are there open questions?

Dr. Alexis C.: We are satisfied with the conclusion, that a mine sank San Diego. Following the war, the U.S. Navy was able to identify which German submarines were operating off the Atlantic seaboard. In fact, the Navy sent a number of ships following the sinking, to assess both what transpired, and see whether there were other mines and threats to other vessels in the area. We have eyewitness accounts of floating debris, that we now can identify as a particular type of mine that was just newly introduced, and not familiar yet to the American sailors.

US Navy divers prepare to enter the water during the wreath laying ceremony for the San DiegoTheo Mayer: This is so interesting, unraveling a mystery. Now, for you personally, when you think back about this project, what are you going to remember the most?

Dr. Alexis C.: This is a project, that developed over a period of years. We were able to visit the site of San Diego, four different occasions. Three of them were in partnership with Mobile Diving and Salvage Unit. These are the Navy divers who have to perform qualification training for their diving credentials, and we offered them a particular objective which was to assess the site of San Diego. One of those projects in September 2017 was a partnership with the University of Delaware, which collected advanced remote sensing data on the site. Then, the final project in July 1918, on the day of the sinking 100 years earlier, we were able to lay a wreath on the site of San Diego, and commemorate the loss of those sailors. I think personally that moment brought everything together, and signified to the intent behind the whole project.

Theo Mayer: The technology for this kind of research, must be evolving a lot. How much of a role does new tech play, in being able to forensically unravel these mysteries?

Dr. Alexis C.: That's a great question. We've seen in the last decade or two, a tremendous advancement in mapping capabilities under water. For our purposes, that's wonderful, because we're able to capture more data at a higher resolution and interpret these sites. There's an act called the Sunken Military Craft Act, it puts in place some protections for Navy ships and aircraft wrecks, that had been lost. As we are able to access these sites more, it becomes even more important for us to be able to educate the public, through the application of technology, about the importance of respecting them. Many are war graves, many carry oil or ordinance. Many are historically very important, and we want to document them as long as we can, and to the best abilities we can.

Theo Mayer: Okay, in summary, what should our listeners take away from this story?

Dr. Alexis C.: I think what stuck in my mind from everything we've learned is, just how incredibly these men prepared for and responded to this event.

Theo Mayer: Great story. Thank you for joining us.

Dr. Alexis C.: My pleasure.

Theo Mayer: Dr. Alexis Catsambis, a maritime archaeologist with the Underwater Archaeology Branch of the U.S. Naval History and Heritage Command in Washington D.C. We have links in the podcast notes to learn more about the San Diego, her demise and the study that revealed what happened.

Links:

https://www.public.navy.mil/surfor/lpd22/Pages/Navy-Commemorates-100th-Anniversary.aspx
https://www.smithsonianmag.com/smart-news/we-finally-know-what-sank-uss-san-diego-during-world-war-i-180971035/ 
https://www.archaeological.org/lecturer/alexiscatsambis 
https://nautiluslive.org/people/alexis-catsambis 
https://www.amazon.com/gp/product/0199336008/ref=dbs_a_def_rwt_bibl_vppi_i0