Operation Castle

I served aboard the USS Curtiss AV-4 from the summer of 1953 to December 1955. I was a Damage Control 2nd and worked out of the carpenter shop. The ship operated out of San Diego, Calif. and was moored at North Island Naval Base. 

When we went to the Marshall Islands in January 1954 on Operation Castle, the ship anchored near a very small island that for all appearances was completely barren except for some palm trees. Later on, we would find out why we were at this particular island. At that time, our mission was classified top secret since as we were carrying nuclear scientists and the actual Hydrogen bomb. We had Marines aboard for security reasons to keep unqualified personnel from going near restricted areas on the Curtiss.  

For recreation, they sent the Ships Company on picnics to this island periodically by rotating the port side one day and starboard another. The ship had brought several cases of beer and liquor to be consumed at these picnics; needless to say, we had quite a few drunken sailors. 
 
I and a couple of other shipmates had taken a senior life-saving course before we went on Operation Castle, so we had to play lifeguard at a few of these picnics. They gave us a little dingy boat to patrol the beach with.  

We were about to find out why we had anchored at this island. On "shot day" we got underway and moved off from the island, I guess a good 25 to 30 miles, and on the morning of the detonation, we lost our picnic island. That is where they had placed the bomb. When the smoke cleared, there was nothing but ocean. I don't remember the actual size of the island. Just guessing, I would say at least three-quarters of a mile wide and a mile long. 

During the Operation Castle tests in the Marshalls, I had the duty assignment of Radiation Monitor. We had to wear protective gear and RBA (Rescue Breathing Apparatus) and carry a Geiger counter to monitor the radiation levels outside the ship after a detonation. After an explosion, they would energize the washdown system for a period of time and then send us out to check levels of radiation. At the time, the scuttlebutt going around was that some of the other ships in our task force got caught in the fallout, and many ship's personnel received high levels of radiation. We heard they shipped some out to hospitals for treatment. 

I do remember on one of the tests; I think the first, we were all above decks to observe the blast, 15 Megatons. The only ones who could face the detonation were the ones with infrared goggles. The rest of us had to turn our backs and cover our eyes for so many seconds until the fireball dissipated. 

Even though we were about 30 miles from ground zero, I remember the heat on the back of my neck was like it feels with a severe sunburn, and the flash was brighter than the daylight, and the sun was out. We received the shock wave several seconds after the blast, and I think every sailor that was wearing hats, lost them. It sure is an experience you never forget.

The operation was really a disaster, as we would find out years later.

Editor: Operation Castle was a US series of high-yield (high-energy) nuclear tests by Joint Task Force 7 (JTF-7) at Bikini Atoll, Marshall Islands, beginning in March 1954. Operation Castle was organized into seven experiments. 

Castle Bravo, the code name given as the first test of Operation Castle, was detonated on March 1, 1954.  Due to miscalculations, it was the most powerful nuclear device ever detonated by the US with a yield of 15 megatons of TNT. That yield, far exceeding the expected yield of 4 to 8 megatons combined with other factors, led to the most significant accidental radioactive contamination ever caused by the United States. 

Because Castle Bravo greatly exceeded its expected yield, JTF-7 was caught unprepared. Much of the permanent infrastructure on Bikini Atoll was heavily damaged. The intense thermal flash ignited a fire at a distance of 20 nautical miles (37 km) on the island of Eneu (base island of Bikini Atoll). 

The fallout from the detonation - intended to be a secret test -contaminated all of the atolls, so much so, that it could not be approached by JTF-7 for 24 hours after the test, and even then exposure times were limited. The islanders were not evacuated until three days later and suffered radiation sickness. They were returned to the islands three years later but were removed again when their island was found to be unsafe. The 23-man crew of the Japanese fishing vessel Daigo Fukury - Maru ("Lucky Dragon No. 5"), was also contaminated by fallout, killing one crew member. Twenty-eight Americans stationed on the Rongerik Atoll were also exposed.

The blast created an international reaction about atmospheric thermonuclear testing, and an awareness of the long-range effects of nuclear fallout has been attributed as being part of the motivation for the Partial Test Ban Treaty of 1963.