Page 11 - BNVTA CAMPAIGN Summer 2020

Mosaic 1 and 2, known as G1 and G2. Training started immediately; they covered the fin with polythene designed by the scientists onboard, and rigged a canvas covering all over the ship.
The ship’s company and the scientists rigged up and streamed various equipment over the side to measure the depth the fallout reached!
The basis of the tests, which had been planned since 1953 by the Chiefs of Staff, was to see what effect an atomic explosion would have on ships, their equipment, contents, and men! HMS Diana and her crew were made available to provide the answers. The tests were planned for May and June, which was the Australia winter, and the winds should blow from the west.
Now there's a lot more to this story, but I don't have the space within the page to include all the info on, so, I’ll skip some. On 16th May 1956, the device exploded. Action stations were called at 1220, and shelter stations at 1325 - this was the expected time of 95% of fallout.
No real effect was felt until 1915, as Diana was in the fallout, and fallout ceased at 2100. At this point, monitoring staff went out to take readings.
Mosaic 2 very nearly didn't happen due to adverse weather conditions. Also, the crew didn't know that G2 was going to be considerably bigger than G1, which was 15kt; G2 was to be 60kt. On June 19th, the flash was observed at 1014 from a distance of 97 miles, with the fireball twice the size of G1. The double crack sound was colossal, and was heard over 200 miles away in Australia.
HMS Diana was signalled that fallout was to be at 1330, shelter stations at 1220, and the first traces of fallout were detected at 1325.
At 1440 the crew had detected radiation in excess of 10 milliroentgens, by 1845 it had dropped to 0.4, then all the work started again, wash down at 2245, and finished at 0020.
There is a lot more to this story to be told, I have an amazing 6-page document, written by Captain John Gower that my Father gave to me to read, and, yes, Dad was on HMS Diana, at Montebello in 1956, for both G1 and G2. He told me a lovely, but funny story about a little dog, called Simba.
parts of which had been unacceptably radioactive! The MOD's attitude remains the same, probably as it is today,
“ If you think you have a case, prove it!! ”
It went on to say that no individual can do this, one must accept it is a battle lost! Captain Gower wrote these words in 1994, 38 years after Mosaic, and passed away in 2007, aged 95. After Montebello, Diana went back to Singapore, and then was called to the Suez Crisis. On 31st October, she sank the Egyptian frigate Domiat, which was engaged in a one-sided gun dual with the cruiser, HMS Newfoundland. This was the last time a ship was sunk by another in a conflict using gunfire alone. There is more to the story, but I have found conflicts, and we know the then Prime Minister
of the UK, Anthony Eden, gave mis-information to Robert Menzies PM of Australia regarding the yield of G2. It was actually 98kt. Some research states that the yield wasn’t known until 1984, and that the weapon was fusion based, hence the bigger yield. Even William Penney thought it was only going to be between 50-60kt - how wrong he was!
To all the Diana, Veterans and descendants, though I prefer to call you family, I hope the information I've written is as close to the truth as I can find out, with the notes I have, If anybody has any information reference Montebello 1956, please contact Andi Jones, BNTVA.
a.jones@bntva.com 0208 144 3080
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Postscript
There was an interesting paragraph in Captain Gower's notes. It wasn't known for some considerable time that the G2 weapon was supposed to have been 60kt (the British Government scientists told the Australian government that it was 62.5kt, yet the Australians proved it was in fact 98kt). The following orders were given, ''They were required to steam through the fallout from two nuclear explosions, to deliberately contaminate our ship and to continue to serve in a ship'',
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