A LITTLE KNOWN ATOMIC BOMB TEST

The scandalous story of poor submarine torpedo performance during the early years of WWII is well known among the trade. The primary cause of the delay in identifying the various torpedo design failures was the lack of warshot all-up testing against realistic targets. Consequently, during the post war period, steps were taken to ensure that operational testing of stockpiled warshot torpedoes against realistic targets was accomplished.

I served a tour of duty in the Bureau of Ordnance in the Underwater Missile Division (Torpedo), during this period and was party to several innovations that proved very helpful in improving the new test programs. One procedure I introduced which proved to be very effective, was to request the Director of the organization which had design control of the particular weapon, to ride the firing vessel along with me during the all-up warshot tests. Most of the Directors were very much in favor of this procedure, and joined in with great enthusiasm.

One such firing exercise involved the nuclear warhead of the Mk 45 torpedo. The exercise was conducted in the Eniwetok Atoll lagoon in the Pacific. The test was an underwater static test of the atomic warhead, which was the same warhead to be used in a nuclear mine. The warhead was suspended at about 100 feet below the surface in the middle of the lagoon. Various ships were stationed in concentric circles at various distances from ground zero. The nearest ship to ground zero was a manned SSK, one of the three smaller submarines built from the keel up. Initially, the SSK was to take station between two barges that supported wire cables under the SSK to enable quick salvage in case of a catastrophe. This concept was quickly changed, as it was believed that the submarine would probably be more vulnerable to damage from the cable barge assembly than from the blast effort.

Accompanying me on board the SSK was Dr. Joseph Henderson, Director of the Applied Physics Laboratory (APL) at the University of Washington. At that time the Lab had design cognizance of the Mic: 45. The Laboratory was basically supported by the Navy similar to the status of the APL at Johns Hopkins University, which was engaged in the missile programs. Several fortuitous circumstances arose in conjunction with the test that may have prevented a catastrophe from occurring.

Dr. Henderson and I flew out to Eniwetok and took up residence in a Quonset hut where we met a friend of Dr. Henderson’s, Dr. Art Foch, the director of a nuclear effects laboratory, and senior scientist of the test. We all socialized at the small Quonset Hut club adjacent to our own hut. The first important event to occur was a delay of a day in the firing schedule, due to instrumental problems in the target area. This delay permitted another social evening with the good doctors. During this session at the bar, I noticed Dr. Foch doing what I thought was some doodling on a bar napkin. As he pointed to the napkin, he said that he thought we may have a problem related to the parabolic curve of the shoreline of the atoll, and that the SSK position at 5000 yards is pretty close to the focal point of the parabola. which could focus the blast. He indicated that maybe the position of the SSK should be moved out to 10,000 yards. Dr. Joe and I thought that made good sense, and we all agreed to the change.

On the day of the shot. the SSK was at periscope depth at 10,000 yards from Ground Zero. Dr. Joe bad brought along a small pocket type battery operated tape recorder. We established ourselves in the small wardroom cheek-by-jowl next to the control room, where the CO, using the periscope, gave a running progress commentary that was keyed into the countdown on the PA system. Finally, the shot went off and all that could be heard was the roar of the blast. I heard many close aboard depth charge blasts during WWII, but this blast dwarfed them all. The SSK was moved bodily up and down. The saturated noise of the blast was gradually replaced by the saturated high frequency tone which lasted several seconds. These results really got our attention. All power and lights were lost, all circuit breakers were opened and an eerie silence prevailed in a pitch black environment. A short period followed during which all hands. including the two of us, were thinking about the Pearly Gates. However, emergency lights were brought on and the PA system came back. Orders to check for leaks were not really needed but resulted in establishing that, despite some controllable leaks, the SSK was still seaworthy but in danger of broaching rather than sinking. All of the test instruments had been knocked out. Dr. Joe’s small tape recorder made the only record of the blast, a copy of which I still have.

After surfacing and analyzing the condition of the SSK, we came to the conclusion that it was operational but not fit for combat. All the gyros, the radar, sonar equipment and fire control system were down. Also, there was a problem with the radio transmitter. It took several days to bring the equipment back on line, particularly the gyro. The magnetic compass was one of the few instruments that withstood the shock.

As an epilogue, Dr. Joe, Dr. Foch and I met at the bar after the test. We came to the conclusion that if there had not been a day’s delay that permitted a scientific analysis to take place on a bar napkin, Dr. Joe and I might well have heard the Pearly Gates clanging behind us.