Operation Sailor Hat

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"Sailor Hat" redirects here. For the piece of clothing, see sailor hat.
500 tons of TNT (20 x 40 feet) awaiting detonation at Operation Sailor Hat.
The blast; the shockwave is visible on the water and a condensation cloud is visible above the fireball.
The crater created by Operation Sailor Hat.

Operation Sailor Hat was a series of three tests of explosives effects, conducted by the United States Navy on the island of Kahoʻolawe, Hawaii in 1965.[1] They were not nuclear tests, instead employing conventional explosives (i.e. TNT) to simulate the effects of a nuclear weapon blast. The purpose of these tests was to study the effects of shock and blast of a nuclear explosion on naval vessels. In addition, seismological data, underwater acoustics, radio communications, cratering, air blast effects, cloud growth, fireball generation, and electromagnetic data were gathered. The former light cruiser USS Atlanta (CL-104), the guided-missile destroyer leaders USS England (DLG-22) and USS Dale (DLG-19), the guided-missile destroyers USS Cochrane (DDG-21), USS Benjamin Stoddert (DDG-22), and USS Towers (DDG-9), and the Canadian Navy's escort destroyer HMCS Fraser (DDH 233) all participated in the trial.

Each "Sailor Hat" test consisted of a dome stacked 500-ton (450 t) charge of TNT high explosive detonated on the shore of Kahoʻolawe close to the ships under test and each test saw the USS Atlanta move closer to the explosion. The first test, called Bravo, occurred on 6 February 1965, with the second test, called Charlie, on 16 April and the last, codenamed Delta, on 19 June.


Cameras recorded the blast effects inside the ships and have shown that the force of the blast was enough to buckle steel walls and tear off heavy radar equipment and send it flying.[2] Although severely damaged, the ships stayed afloat. In addition, two observation blimps were destroyed high above ground by the shock wave. USS England, which was farthest from the blast center, experienced the least damage, the most serious of which was only a dent where a boulder had hit the ship.

The crater left by the blast is called the "Sailor's Hat" crater, and holds an anchialine pool containing Halocaridina rubra shrimp, which have adapted to the conditions in the crater.[3]


  1. ^ "USS England official website". Cg22.ussengland.org. Retrieved 2013-07-01. 
  2. ^ Operation Sailorhat 1965. Retrieved 2014-12-16. 
  3. ^ Brock, R.; J. Bailey-Brock (1997). "An Unique Anchialine Pool in the Hawaiian Islands". International Review of Hydrobiology 83 (1): 65–75. Retrieved 2010-04-01. 

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Coordinates: 20°30′15.31″N 156°40′44.02″W / 20.5042528°N 156.6788944°W / 20.5042528; -156.6788944