The History behind the Operation Hailstone


It was not until 1941 that USA entered WWII because they saw it as a European War. However, there was one attack that finally drew them into the conflict: Pearl Harbor.

There was a series of events that occurred before the attack that led to the inevitable. Not only was Japan considered an ally of Germany and Italy, but there was already a confrontation between the USA and Japan due to commercial interests. Japan was asking for ‘living space’ to carry out trade in the Pacific Ocean as the United States had been blocking Japanese trade since 1940. They were prohibiting exports of steel, scrap iron and aviation fuel and by this, effectively freezing all of Japan’s assets and preventing them from buying oil.

In July 1941 Japan took over Northern French Indochina. The Americans published a public letter asking for the evacuation of the zone which Japan took as an affront and so started to plan an attack against the United States.


Shortly before 8 am on Sunday December 7th 1941, Japanese aircraft carried out a surprise attack on the American fleet based in Pearl Harbor on the Hawaiian Islands. In just 90 minutes the Japanese army managed to destroy seven battleships, around 90 support ships, and 250 aircraft, with a total of some 5,000 servicemen wounded or killed.

The next day the United States declared war to Japan, officially entering into World War II. The war against Japan was always going to be a difficult task because of the breadth and distances of the areas of combat, such as the Pacific Ocean, but the balance of WWII definitely changed. From here on, and over more than three years, a series of attacks were carried out by the United States against the bases of Japan in the Pacific, finally leading to its final attack to Japan.

As divers, we can still see the remnants of these battles today, with the most obvious of these being Operation Hailstone in Truk, but also the lesser known Operation Desecrate One in Palau.


Operation Hailstone – The Japanese Pearl Harbor



During World War II, Truk – occupied by the Japanese since World War I – was reinforced with several warships. After reconnaissance flights, the Americans realised that this tiny atoll was in fact the largest Japanese military base in the entire Pacific theatre. As such, the United States started planning an attack with the main aim to destroy all the ships of the area and cripple the Japanese Imperial fleet.


This task was entrusted to Task Force 58. This naval force had 5 heavy aircraft carriers and four light carriers, together providing the ability to launch more than 500 aircraft. They also knew from intelligence reports that the commander of the Japanese Combined Fleet had transferred most of his fleet to Palau and other Japanese bases. This meant that the atoll was almost undefended. In fact, there was no heavy ship in the area that could cope with the American fleet.

When the attack came it was in two major phases:

  • The first wave of bombers were tasked  with sinking any ships that were anchored in the lagoon with bombs and torpedoes.

  • The second wave was then ordered to destroy the most critical atoll facilities, such as fuel bunkers and munitions arsenals.

The intensive bombardment of Truk was a disaster for the Japanese: all the vessels moored in the lagoon were sunk and two-thirds of the Japanese aircraft were destroyed. Moreover, the airstrip was rendered totally unusable. For the surprise and magnitude of the attack, many historians describe Operation Hailstorm as the “Japanese Pearl Harbor “.


Operation Desecrate One –  Palau



As they had in Truk, Japan had made Palau a defensive military site and an important forward naval supply base. This was despite the Treaty of Versailles, after WWI, forbidding them to do so.

On the long road to Tokyo, the US had planned an attack on Hollandia in New Guinea. As they didn’t want the Japanese providing air support to their troops on the ground from their air bases in Palau, they planned to take them out of the equation. Aware of this, Japan went to great effort to protect the islands by bringing large numbers of fighters and bombers into Koror and Peleliu.

Operation Desecrate One

On March 30th and 31st, the United States navy attacked Palau from the air with one simple objectives: destroy all Japanese aircraft and navy support.

Desecrate One was a huge tactical success: A total of 36 Japanese ships were sunk or badly damaged which made Palau basically inoperable as a naval base. This meant that the US could successfully invade Hollandia (New Guinea) without the worry of Japanese Imperial support from outside.



Would you like to explore these amazing WWII wrecks and learn a little bit more of their history? Then dive with Worldwide Dive and Sail! Truk Master and Palau Siren* both offer itineraries to explore them to their fullest, with the technical and rebreather diving facilities available on board! You just have to choose your destination and we will look after the rest! Contact us for further information!

*With their Special Wreck trips





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