What is it like to experience a nuclear explosion from inside a submarine? An officer whose boat was used as a target vessel in 1958 tells the tale.
I was none too pleased to be assigned to the USS Bonita (SSK-3). The SSK class had a bad reputation in the U.S. Submarine Force. Even worse, the Bonita was not a front-line submarine, a fact I was disappointed to discover soon after reporting aboard as third officer in January 1958. During my 11 months in the boat, her officers and crew would be challenged with numerous unique problems—most related to the Bonita’s participation in two Operation Hardtack I nuclear tests—that required a maximum of flexibility and innovation.
The submarine’s hard-charging skipper was Lieutenant Commander Bob Newbern. While an instructor in the Weapons Department at the Naval Submarine School, he was known as “Tubes Newbs.” Captain Newbern was the main reason the Bonita returned from the nuclear tests at Eniwetok Atoll in one piece rather than ending up on the bottom, thousands of miles from home. Under his leadership, Hardtack became the crown on the submarine’s otherwise tarnished reputation.
An Unsatisfactory Design
After World War II as small, inexpensive hunter-killer submarines, built to sink enemy submarines. Her keel was laid in March 1950 at Mare Island Naval Shipyard, California, and she was launched in June 1951 and commissioned as the USS K-3 in February 1952. Nearly four years later, her name was changed to Bonita, the K-1 became the Barracuda (SSK-1), and the K-2 the Bass (SSK-2).
The Barracudas had rather bulbous bows, which contained the passive BQR-4 sonar. The BQR-4 had become obsolete by the time I came aboard. It was highly effective at slow speeds, but its bearing accuracy was poor. The class was supposed to have a passive sonar with higher bearing accuracy—the BQR-2, carried on a chin mount under the bow—but, as a cost-saving measure, that sonar was never installed. Instead the World War II–era JT sonar, a T-shaped device on the forward deck, was added to give bearing accuracy, but it had very limited range. Atop the bow was an active searchlight sonar used for taking a single ping range just before firing a torpedo. Its range was also very limited.
Each K boat had three General Motors 8-268A diesels, known as “dinkies.” World War II fleet boats had one of these for use as an auxiliary engine, but they were removed from most submarines after the war because the engines were hard to maintain, fairly inaccessible, and only marginally reliable. Those in the K-class boats proved equally painful to maintain. Rarely were all three in commission, and on one occasion at sea all three of the Bonita’s engines broke down. Copper or steel fuel and lube oil pipes were constantly breaking, spewing oil and causing the engine to shut down, with a fire usually breaking out. We counted on at least one such occurrence each day, sometimes once a watch.
The unreliable distilling plants were another of the class’ bad features. Even when on the line they did not make enough water to keep a crew happy. When the Bass was being transferred from Pearl Harbor to San Diego, a submarine rescue vessel had to go out and provide water lest the boat lose propulsion from lack of water to her diesels. Often when short of water, crews resorted to brushing their teeth with canned orange juice.
Finally, the two DC to AC motor generators, affectionately known as 75 KVAs, were also unreliable and nearly impossible to parallel. They were supposed to be shifted daily, but usually one was run until it tripped off the line.
In the minds of those who ran the Submarine Force, the class’ biggest drawback was that the boats were too slow. Senior submariners at that time had all served during the war in fleet boats that could make 21 knots on the surface, end-around most convoys, and get to a firing position in a hurry. According to Jane’s Fighting Ships, the Barracuda class could make 13 knots on the surface, but the best speed of advance that could be counted on was about 6 knots, maybe 6.5, and much less in rough seas. Six knots doesn’t sound so bad for a sailboat, but fiery Rear Admiral Elton W. “Jumpin’ Joe” Grenfell, Commander, Submarine Forces Pacific, thought it was completely unsatisfactory.
Admiral Grenfell decided the class needed to put up or shut up. As a test of operational endurance, he would send the Bass and Bonita on extended arctic patrols. Setting out in August 1956, the Bonita had to stop at Adak, Alaska, both going and returning to take on fresh water and lube oil, this despite carrying multiple extra five-gallon cans of the oil in the sail. In addition, the forward escape trunk was filled with freshwater for showers and washing.
The worst problem during the patrol was self-inflicted.While submerged, the boat collided with a massive iceberg that sheared off the radar, VLF, and HF antennas and damaged a periscope. Radio communications only could be maintained through a not-very-efficient long antenna wire. Everyone on board was proud to make it home to Pearl Harbor in one piece, with no one hurt. But Admiral Grenfell was livid. As soon as the submarine base and Pearl Harbor Naval Shipyard could make repairs, he transferred the Bass and Bonita to San Diego.
So nine months later when a submarine target was requested for Operation Hardtack I’s two underwater nuclear tests at Eniwetok Atoll, Admiral Grenfell volunteered the Bonita, which he had decided to decommission.
Point Naval Shipyard, San Francisco. Four huge pad eyes were welded directly to the pressure hull protruding through the ballast tanks and seal welded to prevent the escape of air from the tanks. These were to moor the boat for the two blasts. Next, a means for venting and blowing ballast tanks from outside the pressure hull was devised. Several 1,000-frames-per-second movie cameras were installed, and an elaborate timing device was set up to actuate the cameras at the exact time of the explosions. Because the Bonita was unlikely to return from Eniwetok in serviceable condition, she was decommissioned and placed in a new category, In Service Special. The crew was also pared down to only those needed for the transit out and to maintain on-board equipment.
During a battery charge the last night before leaving the shipyard, one of the dinkies’ blower mechanisms froze, causing a brief fire. This in turn caused the engine to go hard down, which required a blower replacement. Because the blower was bigger than our 25-inch-diameter hatches, a hole in the pressure hull had to be cut to remove the old blower and install the new one. Most skippers would have stayed in the shipyard to get this done, but Captain Newbern said: “We’re leaving as scheduled. We’ll get it fixed in San Diego.”
This gave our engineer officer time in San Diego to convert one of the two auxiliary ballast tanks, which were used to help trim the boat, into a freshwater tank—backup in case the distilling plants failed. Also, a hydraulic oil tank was modified into a lube oil tank. This solved the lube oil problem, but unfortunately we would run short of hydraulic oil. On the subsequent trip to Pearl Harbor, numerous hydraulic leaks developed, and all hydraulic equipment except for the rudder was isolated from the system. When Captain Newbern asked what else on board could be used as a substitute for hydraulic oil, the engineer reported that Wesson cooking oil was the best available substitute. The cooks didn’t use any Wesson until we reached Pearl Harbor.
While in Pearl Harbor, Captain Newbern made a courtesy call on Admiral Grenfell, who told him in no uncertain terms not to return from Eniwetok with the Bonita, that he didn’t want to spend any more money on a piece of junk. And so, with that send-off the Bonita departed, with 50 five-gallon cans of hydraulic oil secured throughout her sail and superstructure.
Keep the Crew on Board
Arriving at Eniwetok was also quite an experience for a submarine used to operating alone. Hardtack I was a huge enterprise that comprised 35 tests, and the Bonita was a very small cog in a very large wheel. Forty-four ships were involved in one way or another in the series of blasts. Initially, finding the right people to talk with was hard. As someone said, 10,000 men in Bermuda shorts were on a very small island and no one seemed to be in charge. After the Bonita’s officers finally could examine the plans for the first underwater test, code-named Wahoo, they soon concluded the boat’s chances of surviving and not sinking to the bottom were minimal.
The plan for this deep-water test called for a nuclear device to be secured at a depth of 500 feet in 6,000 feet of water. The unmanned Bonita, suspended from large floats, would be 4,000 yards away with a bow-on aspect and an open outer torpedo door (simulating conditions if a wire-guided torpedo was the delivery weapon).
“Why don’t we do the shallow-water test first?” Captain Newbern asked officials.
“That’s not what the schedule calls for,” was the reply.
“Well, can the schedule be changed?”
Characteristically, the captain would not accept this answer. After much discussion in a wardroom meeting, Captain Newbern, his officers, and a representative of the Bureau of Ships decided the only way for the boat to survive the Wahoo test was for her crew to remain on board. We then got out slide rules to come up with a safe distance and agreed on 9,000 yards with a beam aspect and all torpedo doors shut. The captain then volunteered all of us to be on board except the executive officer, who would remain in charge of crew members who stayed in a support ship, the USS Hooper Island (ARG-17). Captain Newbern ordered the officers to solicit a strong group of volunteers to remain in the submarine during the test and then went to see the chief of staff to the admiral in charge of Hardtack.
When the skipper proposed the modifications for the deep-water test, he was told, “No, do it as planned.” He replied, “Well, then, I’d like to send this message.” From a folder he pulled a typed sheet of paper addressed to the chain of command, including the Chief of Naval Operations, requesting that he be absolved of the loss of the Bonita. The chief of staff blinked, told him to hold the message, and said he’d see what he could do. Two days later word came back that the boat would be manned. The range of 4,000 yards from the blast was too risky, so the Bonita was moved out to 6,000 yards.
Wahoo Shakes Up the Sub
On the day of the Wahoo test, 16 May, the Bonita got under way early. A trim dive was made in deep water to ensure the water load in the submarine was perfectly balanced, and the submarine took station at periscope depth slowly circling the blast point at a range of 6,000 yards. Inside that circle were three old destroyers, a former Liberty ship, and a submarine mockup target, all unmanned and secured in place by deep-water mooring. The nuclear device was suspended from an anchored barge, which had antennas to receive the detonation signal. The long countdown came over the radio to all in the area.
In accordance with plans to secure the Bonita for survival, she was rigged for depth charge, which meant all watertight doors were dogged shut and bulkhead flappers in the boat’s ventilation system were closed. All seawater lines into the boat were secured during the countdown so that overpressure from shock waves would not cause any internal ruptures.
At 1330 Wahoo blew. Initially, to some the blast sounded like a freight train running over the boat. The Bonita shook violently, light bulbs broke, dust and debris flew everywhere, and all the lights went out as the 75 KVA tripped off the line. It looked just as it does in a Hollywood movie. The on-watch engineman, despite soiling himself, ran as fast as he could to get the KVA back on the line.
Three separate shock waves hit the boat. The first was the direct wave; the second, a bit milder, was the bottom reflection; and the third, milder still, the surface reflection. Later the engineer pointed out that there would have been serious trouble if the direct shock wave and bottom reflection had arrived much closer together. After surfacing to return to the Hooper Island, further inspection found seawater in both escape trunks. The reason would not be understood until after the second test.
A simple tape recorder had been rigged to record conversations in the control room and conning station. It was great fun listening to the tape, hearing voices rise in octave levels as the countdown neared detonation time. When the blast occurred, a brief roar was heard on the tape, then nothing; the follow-on shock waves had blown the power cord out of its socket.
Film from the 1,000-frames-per-second cameras showed a ripple effect as the shock waves hit the steel hull, wrenching it and all the mounted equipment in the control room. A new sophisticated fire-control system was damaged so badly it couldn’t be fixed. If in combat, the Bonita wouldn’t have been able to continue fighting.
The Second Big Blast
The boat got under way for a rehearsal of the second underwater test, code-named Umbrella, early in the morning on 4 June. The Submarine Force was more interested in the Umbrella test because a nuclear-tipped torpedo was in the design stage and the force wanted to know the stand-off range—the distance at which a submarine safely could fire the torpedo without sinking along with the target boat. The test would take place in Eniwetok’s lagoon, where the average water depth is 100 feet. The boat’s position would be bow on to the nuclear device at a range of 2,950 feet.
During a rehearsal, chains with heavy weights attached were secured to our four pad eyes. The diving officer trimmed the boat so she would be at periscope depth with positive buoyancy. The outer door to one torpedo tube was opened to simulate the firing of a wire-guided torpedo. When all was ready the crew departed on board a fleet tug. The engineer and Captain Newbern were the last ones off. They opened the vent valves topside; the Bonita took 23 minutes to submerge. Divers in scuba gear then went down and opened the blow valve topside. The boat surfaced nicely, though at a slight down angle, with a diver riding up on deck and securing the blow and vent valves. Now all was ready for the actual test. The crew reboarded to recheck everything and remained in the sub while she was moored.
On 9 June, it was for real. This time all escape trunk hatches were wired shut to keep them from lifting off their seats when the blast deformed the hull. It was hoped that no seawater would get in this time. The earlier sequence was repeated. After evacuating the boat, the crew waited out the test on board a fleet tug.
At 1115, Umbrella went off as scheduled, and it was quite a show. After a diver went down and opened the blow valve, almost everyone sighed with relief when the Bonita popped to the surface. She was checked for radiation, and when the all-clear signal was given, the tug returned the crew. The engineer was first aboard. He unwired the escape-trunk hatches and proceeded below with a carbon-dioxide sniffer to check each compartment. He again found water had entered the boat through the escape trunks. It was later learned that during both tests a very low-pressure wave followed the initial high-pressure shock wave. The low pressure lifted the hatches off their seats, allowing in seawater. When the air in the boat was determined to be okay, the crew embarked and prepared her to return to the Hooper Island as soon as the weighted chains could be removed from the pad eyes.
A Hero’s Welcome
The next day there was another new problem. The Hooper Island took radiation readings that revealed the Bonita’s sailors were all slightly radioactive. No one could come aboard the ship without first being checked with a radiation detector and then walking through a “shoe-washing” solution. The boat next had to be made ready to return to Pearl Harbor and San Diego.
When the boat had surfaced following the Umbrella blast, sand and coral wedged in exterior nooks and crannies measured two roentgens of radiation. (The operation’s maximum permissible exposure was five roentgens.) This level had to be reduced to ten milliroentgens—one-hundredth of one roentgen—prior to our arrival at Pearl Harbor. More than a week of hard work scrubbing and using fire hoses to wash down the Bonita’s topsides and superstructure fixed the problem. Just before leaving Eniwetok, the crew painted a new insignia on each side of the submarine’s sail: an atomic bomb blast with two hash marks underneath.
Upon her arrival in Pearl Harbor and later in San Diego, the much maligned Bonita was hailed—even by Admiral Grenfell. In his formal report of the two tests, Captain Newbern recommended that a submarine or surface ship never again serve as a target for such tests. He’d learned from some of the scientists on Eniwetok that the same kind of information the tests’ target vessels yielded could be obtained from shaped charges exploded at varying distances, which could be correlated to an atomic blast of any magnitude. The Submarine Force took these conclusions to heart, and no U.S. submarine ever again had to endure a nuclear test.
Liberty on Elmer Island
During Operation Hardtack I, the only place enlisted men could go for liberty was tiny Elmer Island, where a shark net protected a very small beach. Beverages were sold at an open-air pavilion. Beer and any kind of highball went for 10 cents each; soft drinks were 15 cents. Because of the number of ships present and the small size of the recreation area, only 10 percent of each ship’s crew was allowed on the island at any one time. The Bonita’s Captain Newbern quickly got that changed for our crew; afterward the boat could send up to half of her crew to Elmer.
The only way to get to the island was by “Mike Boats” (LCM-8s), which picked up liberty parties about noon and returned them in the early evening. The shore patrol assigned to this so-called recreation island comprised three or four petty officers and one officer. One can readily imagine what happened in the hot afternoon sun with alcohol cheaper than soft drinks. Sailors got very drunk.
One liberty party overpowered the shore patrol, stripped them buck naked, and sent them back to their ships with no clothes. A few of our sailors got in trouble after drinking too much, but for the most part the crew behaved themselves. After the Wahoo test, they defeated squads from larger ships to win a volleyball tournament, which perked up morale and kept it high for the Umbrella test.
Captain William C. Green, USN (Ret.)
Captain Green graduated from the University of Southern California’s NROTC program in 1952 and was immediately assigned to the cruiser USS Helena (CA-75) in Korean waters. Next came duty in various submarines, culminating in command of the USS Tunny (APSS-282), which was specially configured to conduct unconventional warfare in Vietnam. Later, he served in many intelligence assignments including assistant naval attaché in Moscow, defense attaché in Rome, and analyst at the National Security Agency. Captain Green retired from active duty in 1983.