Scientific rehearsals were held on 12 and 13 September. This was followed by an operational rehearsal on 19 September, which included fully assembling the bomb, since the radioactive components had arrived the day before on a Sunderland. Penney arrived by air on 22 September. Everything was ready by 30 September, and the only remaining factor was the weather. This was unfavourable on 1 October but improved the following day, when Penney designated 3 October as the date for the test. The final countdown commenced at 07:45 local time on 3 October 1952. "Plym" was moored a few hundred meters west of T2 (approx 20°24'16"S, 115°34"E). The bomb was successfully detonated at 07:59:24 on 3 October 1952 local time, which was 23:59:24 on 2 October 1952 UTC, 00:59:24 on 3 October in London, and 07:59:24 on 3 October in Perth. The explosion occurred below the water line, and left a saucer-shaped crater on the seabed deep and across. The yield was estimated at . All that was left of "Plym" was a "gluey black substance" that washed up on the shore of Trimouille Island. Derek Hickman, a Royal Engineer observing the blast aboard "Zeebrugge", later said of "Plym", "all that was left of her were a few fist-sized pieces of metal that fell like rain, and the shape of the frigate scorched on the sea bed." The bomb had performed exactly as expected.