In 1946 a fleet of 242 ships, among them some of the most famous of World War II, assembled within the lagoon of Bikini Atoll, 4,500 miles from San Francisco. Known as 'Operation Crossroads', 42,000 scientists and US military personnel gathered to assess the atomic bomb's effect on warships in the world's first nuclear weapons tests. The first test, Able, on 1 July 1946, was an airdrop like those used at Hiroshima and Nagasaki. The second, Baker, on July 25, was an underwater detonation that resulted in a column of water a mile high. As a weapons test site, Bikini Atoll was eventually the site of a total of 23 atomic and hydrogen bomb explosions between 1946 and 1958. Today, its lagoon is a graveyard for some of the dozens of World War II ships that served as guinea pigs to test the effects of an atomic bomb on naval vessels. One of these vessels was the USS Saratoga.
Exercise Saratoga Crossroads set out to do many things during the 26 day expedition to Bikini Atoll, Kwajalein Atoll and Truk Lagoon, but the primary aim for the 13 man military team was always to dive the USS Saratoga aircraft carrier. Known affectionately, by those who know her, as 'Sara', she is the most famous and most mourned of all the ships sunk at Bikini. At 880' she is longer than the Titanic but has the considerable advantage of sitting upright and fully intact in a maximum depth of 57.5m on the sand floor of a tropical lagoon. Sara was commissioned in 1927, weighs 39,000 tons and carried fuel and ammunition loads during the test at 10% of capacity and 67% capacity respectively. She was reported sunk by the Japanese seven times during World War II and received seven battle stars. Sara was moored approximately 300 yards from the Baker Zeropoint. The blast unleashed one of the greatest waves ever known. Millions of tons of water were carried upward and the first blast wave lifted her stern 43' and her bow 29'. The second wave slammed her starboard side, cleared her decks and pushed her about 800 yards. The thousands of tons of water falling from the blast column caused her flight deck to collapse and breached her 1000 watertight compartments. She took less than eight hours to sink - 'As if striving for immortality', wrote Hanson Baldwin, military affairs correspondent of the New York Times, 'the 'Sara' lifted her white numeral '3' - third carrier of our Navy - high into the sun before her bow slipped slowly under.'
Fifty-three years later, we left Bikini Atoll on board the dive boat Bravo and headed out to dive Sara. After 15 months of planning and 4 days of travelling we had finally arrived. Today, Sara is marked by 3 large cylindrical buoys one at the bow, one at the stern and one on the bridge. You are immediately in no doubt as to her size - it is a long way between the buoys! The first diver in saw a shark before he had even left the surface and we were joined by two more as we made our descent onto the massive wreck. Swimming down past the bridge and along the starboard side of the flight deck you are immediately aware of the majesty of the ship. As we swam off the edge of the flight deck we found a 5" gun position. It was at one of these positions that a marine gun crew had been burned alive in February 1945 as they attempted to keep kamikazes at bay. In stark contrast a turtle now occupied the position; further adding to our impression that she was in some way a 'friendly' wreck.
Nevertheless, we were initially disappointed by the green colour of the water. We had waited so long to dive Sara and visualised this moment 'in blue' so many times that this was difficult to accept. Fortunately, the water was to become significantly bluer as the week progressed and, in any case, the underwater sights did not once fail to considerably outweigh the colour of the water.
That first dive was theoretically a no decompression dive. In practice that meant we only had a few minutes of decompression. Subsequent dives were to have far more as we found ourselves diving depths up to 50m for bottom times as long as 28 minutes twice a day. However, once bottom time exceeded 25 minutes on our Aladin Pro computers, the decompression penalty simply went through the roof! All dives were carried out using air computers but decompressing on Nitrox mixes of 55 - 80%. This air schedule often gave us decompression stops in excess of an hour. Nevertheless, we would always do a minimum of 5 additional minutes once the computer had cleared. Ascents were exceptionally slow with stops starting with one minute at 25m and getting progressively longer until the majority of the time was spent at just 3m. We carried twin 12 litre air cylinders and a choice of either a 7 litre side slung Nitrox cylinder or a 'whip' provided from the surface once back at the decompression bar. There was never any problem getting back to the bar but we had enough air and delayed SMB's just in case.
Many technical divers reading this will question the excessive amount of stops carried out but it must be remembered that the expedition could not afford to have an incident. Not only were we diving way beyond the remit normally allowed on military diving expeditions, but we were a long way from help. Effectively we were on a pedestal from which any fall could easily have become a very public affair subject to official investigation.
We did a total of 13 dives on Bikini Atoll, of which 5 were on Sara. Of these, it was the penetration of the hangar deck that was most memorable. The weight of water falling from one mile up as a result of the Baker explosion had somewhat dented the flight deck as if indeed 'Godzilla had stamped on it'. The effect of this was to somewhat reduce the height of the hangar deck in places which, coupled with a reasonable amount of silt, often total darkness and no line, kept the adrenalin running. Of course, as a rectangular space, navigation was, in theory at least, no problem. The first thing you see as you swim down the huge elevator shaft and enter the hangar deck is a rack of 500lb aerial bombs. There is some dispute as to whether these are live or not but we didn't touch them just in case! Looking up at the ceiling you notice that the light fittings are still intact. A little further in we came across 4 airplanes stowed, wings folded, on the hangar's starboard side. The first three are 'Helldiver' single engine aircraft and the fourth an 'Avenger' torpedo bomber. Every instrument remains mounted in the instrument panels except the clocks which were taken out because they were too attractive an item and might have been stolen! Next we come across Mark 13 torpedoes, many tumbled and loose on the deck. Weighing a ton each it was weapons like this that were responsible for the sinking of the Japanese battleship Yamato.
At this point the flight deck above hangs down close to the floor forcing us to have to swim carefully to avoid stirring up the silt as we swim in total darkness to the other side of the hangar deck. Here we came across a single 1000lb bomb sitting all on its own as if it were simply too powerful to be associated with the other weapons!
The single most impressive view of the wreck has to be the bow. Swimming down the shot you were able (if so inclined) to pretend that you were an airplane coming into land and swoop down onto the remains of the Teak flight deck! Then (unlike the planes) you dived off the blunt nose of the overhanging flight deck to see the wide hull, covered in whip corals, disappear below you complete with anchor chains drooping listlessly. These broke free from their 10 ton mooring blocks during the blast and serve as a poignant reminder of how she came to be there. From the bow it is a long swim over the flight deck to the bridge. However, on the way you come across a nine-foot high steel pipe blast gauge tower known during the tests as 'Christmas trees'. On these were mounted ruptured foil gauges for recording peak pressure in air. These consisted of quarter-inch-thick brass plates with round holes of various diameters bored through them. Tinfoil was sandwiched between the plates and mounted on an airtight steel box. The greater the pressure, the smaller the diameter the ruptured foil would be. They serve as yet another reminder of the scene here 53 years ago and double as a luxury home for small fish!Sara's bridge was on the way up from most of the dives we did on her and we got to know it well. Most of the instruments remain in place with radar and communications equipment readily identifiable. Nothing has been removed from the wreck and the US Navy did not intend her to sink so it is all there!
I was the last one to leave the wreck on our last wreck of the expedition. Momentarily, I was alone with my thoughts on the bridge - I did not want to go up but an impatient buddy and mounting decompression forced me to bid farewell.
During our week on Bikini Atoll we dived the USS Saratoga (aircraft carrier) five times, HIJMS Nagato (battleship) twice, USS Lamson (destroyer), USS Arkansas (battleship), USS Carlisle (attack transporter), USS Anderson (destroyer) and the USS Apogon (submarine) plus one dive on the reef. Bikini Atoll as a whole was an incredible and totally unforgettable experience. The diving operation is small but totally exceptional in terms of the quality of service it delivers. Fabio Amaral (divemaster) and his team do not treat you merely as customers but as fellow team members. The dive set up is purpose built from scratch and Oxygen is made on site. They can also provide Trimix. The wrecks are in a class of their own which left us disappointed by Truk Lagoon! I can only hope that one day I will get the chance to dive Sara again.

The Team would like to thank the following for their support: Major Sponsors: Headquarters British Forces Gibraltar; Joint Services Expeditions Trust Committee; Traser (UK) Ltd; Apeks

Minor Sponsors (commercial): OMS Drysuits; Otter Watersports; AP Valves; O'Three Wetsuits; Seven Tenths; Portland Dive Centre; Markat; Custom Divers; MGE Engineering; RED UK

By Major Andy Reid.