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MWL 251’s commanding officer, Lieutenant George Halley, described the blast,
“At 1145 all the hands mustered on the port side of the boat deck and the countdown commenced at 1148... At 1151, although we had our backs to Trimouille Island,
we experienced a blinding flash of intense magnitude, followed by a slight burning feeling across the back of the neck and at the back of the knees. This was only momentarily (sic) and the intensity of the heat resembled the warmth of the sun on a December day. At ‘H’ plus 5 seconds, the hands were permitted to face the direction
of Trimouille Island. On looking round we observed the last stages of the fireball. It resembled a huge oil fuel fire. As soon as it had Contracted a thick mass of dark grey cloud rose in a vertical direction at a terrific speed. The familiar mushroom cloud soon developed. Shortly afterwards at approximately H plus 60 seconds, the blast wave was felt, company turned towards Alpha Island and on this occasion the glare of the fireball seemed to last longer and was more intense in its magnitude.”
After detonation at 1150 on 16 May, HMS Narvik and Alert entered the Parting Pool; the Radiological Group wore full protective clothing and entered the lagoon in a cutter, conducting a survey and retrieving instruments. A decontamination tent with a pumped water supply allowed the group to wash themselves before returning to the HMS Narvik. The ship’s evaporators weren’t run due to fear of radioactive contamination.
A Varsity aircraft surveyed the Onslow to Broome coastline one day
The Cameron Society on the docks at Freemantle.
after G1’s detonation and reported there was no radiation. Maddock visited the crater on 25 May to take soil samples and collect film badges from Hermite Island.
The Canberra bombers were monitored and decontaminated on their return to RAAF Pearce.
The results of the test showed a yield between 15-20kt of TNT, which had been anticipated, however the cloud rose to 21,000ft rather than the predicted 14,000ft. Although the implosion system had performed perfectly, the boosting effect of lithium deuteride was negligible. The fallout moved out to sea, but then reversed direction across northern Australia. Radioactive contamination from G1 was found on aircraft at Onslow, indicating that fallout had indeed blown across mainland Australia.
If anyone could survive a holiday on the Montebello Islands, it was Mrs Taylor. She took fresh water with her, and described a typical meal as “turtle soup, oyster patties, turtle steak and eggs, together with crayfish and schnapper.”
What is striking from the article is her ecological description of these uninhabited islands,
“Far from being the dismal wastes you would imagine, the islands are picturesque, surrounded by clear water, lagoons and coral reefs. To drift over the reefs in a small boat and to look down into the water is a coral fairyland. The neighbouring sea abounds in huge schnapper, which is excellent eating. The reefs are encrusted with outsize oysters, while there are shoals of green back turtles – good for food – and hawksbill turtles – valuable for their shells... A great deal of pearling takes place off the coast of Trimouille, and during the hurricanes the luggers find perfectly secure anchorage in the lagoon of Hermite.”
On 19 June 1956, G2, the second atomic blast in less than a month, this time at Alpha Island, was detonated. This was recorded as a 98kt atomic bomb by the AWRE despite the UK government recording the blast
at 60kt. The colossal blast far outweighed what the UK had agreed with the Australian government, and Captain John Gower was ordered
CAMPAIGN SUMMER 2021