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. 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.