REMINISCENCES | Atomic bomb tests on Christmas Island (or how we had a little fun with the US Navy)

This episode started off with an atomic bang and ended in a whisper. But before the atomic explosion occurred, our fisheries research vessel Charles H. Gilbert had some unexpected fun with a US Navy destroyer escort.

In 1962, the US government conducted a series of 36 atomic bomb tests in the air around Christmas Island. They were part of Operation Dominic and we monitored one of them. Christmas Island is located 1,200 miles south of Honolulu and is the largest land area atoll in the world (about 300,000 acres). At the time of the atomic testing, it was a British Crown Colony but is now part of the sovereign nation of Kiribati (pronounced “Keery Baas”).

In 1960, the population of Christmas Island (Kirimati) was two or three hundred I-Kiribati (residents, pronounced “Eee Keery Baas”) and four Europeans. The population in 1962 was unknown to me.  It is believed Christmas Island was named by Captain James Cook RN, the great English navigator, who discovered it on December 24, 1777. The island was completely uninhabited, and he was there for only a few days, departing for Hawaii on January 2, 1778.

“As we kept our Christmas here,” Cook is quoted as saying, “I called this discovery Christmas Island.” Some historians dispute this naming, however.

The US Atomic Energy Commission (USAEC), which controlled US nuclear weapons testing, wanted to know the radiation level in fish found below the air burst of the bombs, which were detonated about 40 or 50 miles south of Christmas Island. Several hearsay reports cite the altitude of the air burst. One says 75,000 feet, another says 10,000 feet. The yield of the explosion we monitored was the equivalent of about 500,000 tons of dynamite, not a small bang (estimate derived from Operation Dominic website).

“For all practical purposes, our vessel looked just like a Japanese tuna longliner.”

To obtain the radiation level in the fish, the USAEC subcontracted the job to two agencies: The Radiation Laboratory of the University of Washington and the US Bureau of Commercial Fisheries (BCF), now known as the National Marine Fisheries Service. Under the direction of BCF Area Director John C. Marr, the fishing was assigned to Charles H. Gilbert, with me on board as Field Party Chief. Gilbert carried out three cruises (56, 57, 59) in the Line Islands area at the request of the Atomic Energy Commission. This episode describes what happened during cruise number 56.

Gilbert was 120 feet long, 21 feet wide with a draught of 11 feet, Its bridge and deckhouse were aft, and it was colored white. It was a multi-purpose fisheries research vessel specialising in longline fishing for deep swimming tuna, pole and pole and line fishing for surface schools of skipjack tuna, and side trawling for midwater animals. For all practical purposes, we looked just like a Japanese tuna longliner, the fishing vessels that can fish a thousand hooks in a line 30 or 40 miles long.

There were 12 in the crew, plus three scientists. The chief radiological scientist was Dr. Ralph Palumbo of the University of Washington’s Laboratory of Radiation Biology. Ralph was a short person but built like a professional wrestler. He used to amuse himself by climbing hand over hand up the halyard used to raise Gilbert’s sail when the sail was not in use. From the deck to the top of Gilbert’s mast, this was about 50 feet.

At a speed of seven or eight knots, it was expected that Gilbert would take about a week to reach Christmas Island from Honolulu. We were cautioned to be aware that the US military was conducting the testing. Gilbert did not have a c.w. radio (i.e., dot dash dot) capability, so we would have to rely on voice radio communications. The first four or five days were routine – getting the fishing gear ready, thawing out the frozen bait, and the normal sea routines of a small ship.

Things were about to change, however, because the military had established a “no go” zone as an area that was about 300 or 400 miles on each side of a square with the island in the middle. They were not kidding, for one morning at 4 a.m., I was awakened by a tremendous roar from a large aircraft flying just overhead. It turned out to be a military reconnaissance aircraft that had probably picked us up on its radar and then illuminated us with its huge bright searchlights. We assumed it told somebody else about the contact, but we did not know what to expect after that.

The basic problem was that we were an odd-looking civilian ship during a 100 per cent military operation. The military did not know quite what to do with us, especially since Gilbert normally did not fly the American flag. Why it did not do so, I don’t know.

“We got fists shaken at us, arms gesticulating, caps waving, and finally several of what can be called the politically correct ‘ethnic’ salute.”

A day or so later, we were casually steaming towards Christmas Island at eight knots when somebody called out, “There is a ship on the horizon coming our way.” The weather was clear, and the time was mid-morning. We all watched as this ship became larger and larger and was really going fast, a lot faster than eight knots. We soon saw that it appeared to be a US Navy destroyer escort and was going so fast it “had a bone in its teeth,” meaning it generated a big wave by its bow.

Soon, the ship – which we concluded was in fact a destroyer escort (smaller than a destroyer) – was just astern and in another minute was just off Gilbert’s port side, perhaps only 100 feet away. We could see people gesturing at us, using binoculars (Our vessel’s name in English was visible, although not too big.), and making signs that said, “Who are you?”

Our crew was a chop suey mixture of various races. The captain was of Japanese descent (He was a US Army combat infantry veteran of World War II.), the navigator was Hawaiian, and the rest of the crew were either of Japanese, Hawaiian, or Filipino descent, except the assistant engineer, who was Caucasian.  The three Caucasians on board – myself, one radiological scientist, and the assistant engineer – stood under the bridge awning wearing broad-brimmed hats, thus hiding our ethnicity.

For some reason, our voice communications were not working – maybe we used the wrong frequency.  More hand waving, use of binoculars, etc. ensued – this took about 10 or 15 minutes. Finally, with a gleam in his eye, our captain took the ship’s American flag out of a drawer and gave it to one of the crew with instructions to go aft to the fantail and run it up the short flagpole, which he did.

The reaction from the destroyer escort was instantaneous. They were angry. We got fists shaken at us, arms gesticulating, caps waving, and finally several of what can be called the politically correct “ethnic” salute.  Formerly called something else, an ethnic salute is when a person extends his or her arm and with the hand of the other arm slaps it into the elbow crevice.

The destroyer escort finally determined we were not a Japanese longliner – which is exactly what we looked like – and waved us on, much to the merriment of our crew.

“There was absolutely no radiation detectable in the fish we caught.”

The next day found us at Christmas Island at anchor outside the atoll’s mini lagoon. I went ashore and consulted with the US Navy captain in charge of operations. He told us to head for a spot about 50 miles east of Christmas Island and wait for coded instructions by voice message.  The code words “The tuna are biting today”meant the shot was on the next day at 8 a.m. “Fishing is very bad” meant the shot has been cancelled, meaning we were to await further instructions.

We did as instructed and a day or so later, from a position 50 miles away, we watched a nuclear explosion.  We all wore dark glasses and after first watching the air burst, which obliterated the sun, we felt a small heat wave pass over Gilbert.

Nuclear explosions experienced from even 50 miles away are still very humbling.

The following day, we went longline fishing for deep swimming tuna right under the position of the air burst, sometimes called ground zero. After a fair catch, we cut the tuna up into pieces for Drs. Palumbo and Nakatani to check for radiation. They were mainly yellowfin tuna weighing over 100 pounds each.

Results: zero, nothing, zip, de nada – there was absolutely no radiation from the air burst detectable in the fish we caught. Dr. Palumbo, however, showed me a printout of the results of several other nuclear explosions that occurred years before and nowhere near Christmas Island. What happens is that the explosion residue somehow falls into the ocean, gets into the food chain, and eventually shows up in climax predators like tuna. On recounting this work after returning to Honolulu, several other biologists told me we were crazy to have done it. However, our film badges showed that no radiation from the bomb burst reached us.

The USAEC must have been very pleased that the shot did not contaminate any tuna in the neighbourhood, but on the other hand, we think the captain of the destroyer escort was mightily annoyed at our behaviour. We later were told that the in-air residue of the explosion was blown southwest by the winds to the general location of the Marshall Islands. Amata Kabua, later to become the first President of the Marshall Islands in 1979, was also said to be have been extremely annoyed at this.

The above article is an excerpt from Swimming with Fishes, Dr Bob Iversen’s memoir detailing his experiences as a fishery biologist. It is reposted here on Baird Maritime with the author’s permission.

Submissions wanted! Do you have an exciting, amusing, or downright dangerous anecdote from your time in the maritime world? Send your submissions to: [email protected].