"We did not expect any major radiation fallout, which has been proven wrong."
On arriving back in Auckland, the crew received a "hard lying" bonus for making the voyage. It amounted to $3.96 a man.
But the Labour Government was grateful to them and to the crew of HMNZS Otago, which they relieved at the test zone from the role of silent witness.
As a public relations exercise, it was an extraordinary success.
Each frigate saw an atmospheric test held at Mururoa Atoll in French Polynesia.
Mr Colman, the father of three young daughters, spent 46 days on board both frigates, which became the "go to" information centre for international media on what the French military was up to.
Defence Minister Arthur Faulkner said: "The world is watching, because we are here."
France had conducted atmospheric nuclear tests at Mururoa and Fangataufa Atolls since 1966, and New Zealand's Prime Minister, Norman Kirk, ordered the warships to passively patrol international waters to stimulate world opinion and attract wider support for the rights of Pacific nations.
At 8am on July 1, HMNZS Otago was idling 56km off Mururoa when the nuclear device, slung from a balloon, was detonated.
New Zealand Press Association correspondent David Barber was on board and reported a mushroom cloud forming and rising after "an orange-red fireball erupted through a layer of cirrocumulus cloud over Mururoa, spreading out about 1200 feet [365m] across and burning at an estimated 46 million degrees centigrade at its centre".
Those on HMNZS Canterbury saw a smaller detonation on July 29, which NZPA reported as a "fluffy white powder puff fragmented within 10 minutes by the wind".
The representative of the National Radiation Laboratory on board the warships said the yield of the blast the Otago crew saw was about 5 kilotons, or a quarter the size of the bomb that destroyed Hiroshima.
The explosion seen from Canterbury had a much lower yield and all radiation instruments registered zero fallout.
Rumours to the contrary have not stopped since.
In July 1974, the Herald said reports circulating in Auckland claimed sailors were suffering from cancer after sailing to Mururoa Atoll and that two had died.
Twelve sailors were said to be in the Devonport Navy base hospital.
A Navy spokesman said several men in the hospital had cancer. He refused to say how many, but said it was fewer than 12.
Only one man had been in one of the frigates that sailed to Mururoa Atoll. The type of malignancy he had was not a likely result of exposure to radiation, said the spokesman.
The number of men with cancer in the hospital was similar to any cross section of the population, the spokesman said.
Mururoa Veterans' Society president Peter Mitchell, who was on HMNZS Canterbury, is expecting about 60 veterans to be at this weekend's reunion.
"From the 500, 180 have died and quite a few have suffered some form of cancer," he said.
The frigates were equipped so that any radiation was washed off into the ocean, but he had the impression that no one had thought about preventing the men ingesting radioactive water.
"The frigates sucked in 25 tonnes of saltwater a day into desalination and filtration plants," he said.
"About 24 tonnes went into the boilers to make the ship go and create electricity and the other tonne was for us to drink, wash, cook, wipe down the tables and scrub the decks.
"There is no known filter for radiation in the water so it was coming inside the ship.
"No one thought of that great hazard - the water we were sailing in was affected."
The society knows of 42 Mururoa veterans receiving war disablement pensions.
"But we are wondering exactly what have we passed on to our children and to their children.
There is no follow-up on their health."
Veterans' Affairs Minister Michael Woodhouse was invited to comment on issues raised by the veterans but was unable to respond yesterday.
A spokeswoman for his office said the Government acknowledged the Mururoa veterans' service through a War Disablement Pension, which is available to veterans exposed to nuclear radiation. Mururoa veterans are also eligible for the NZ Special Service Medal
Mr Mitchell said the only real hope for veterans in a decade was the work of Dr Al Rowland, the now-retired lead researcher of Massey University's Institute of Molecular BioSciences.
This work was focused on 50 of the 551 New Zealand Navy men who witnessed nine British nuclear blasts during Operation Grapple at Christmas Island and in the Malden islands in Kiribati in 1957 and 1958.
Researchers also tested blood taken from 50 former servicemen of the same age who had not been exposed to elevated levels of radiation.
In April 2006, the Herald reported Dr Rowland saying a small but statistically significant level of genetic damage had been found.
"Taking all confounding factors [like smoking, alcohol and medical x-rays] into account, we are left with only one other interpretation of what it is about this group that's different to the control group: they went to Operation Grapple."
His work on chromosome damage - the first step in the formation of cancer - gave hope of compensation to thousands of men from Britain, Australia, Fiji and New Zealand.
The research was commissioned by Nuclear Test Veterans' Association chairman Roy Sefton, who sought Government acknowledgment that men were harmed in their teens and had no choice on whether they went to Mururoa.
Tony Cox, who was on HMNZS Otago and heads the Rimpac veterans' rights organisations, said an attempt was being made to convert Dr Rowland's findings to apply to the Mururoa veterans.
"Just because the Government did not accept the Rowland study does not mean that it can't come up for a review."
Mr Cox said he had cancer of a type that was contracted only through exposure to ionised radiation.
"Norm Kirk is not around so I can't say remember me?
"Kirk stood with me at the port waist of the ship, looked me in the face, and said 'you'll be all right son. If you or any of these guys have problems we will look after you'. Old age does play a part but it's brought on a hell of a lot more by being thrown into the things we have been."
Between 1966 and 1974 France conducted nuclear weapons tests in the atmosphere at the atolls, including 41 detonations and five safety trials in which weapons were destroyed with little or no release of nuclear energy.
After 1974, atmospheric testing was abandoned in favour of underground tests and between 1975 and 1996 a total of 137 tests took place.
The programme was stopped in 1996.
But associations for military veterans and Polynesians who worked on the test sites say cancer rates among their members are almost twice those of the general population.
This month, the Mururoa e Tatou - a Tahitian group - said newly declassified French military documents showed radioactive fallout from Mururoa testing was more widespread across French Polynesia than first thought.
Read more: Sick children and friends dead from cancer make vet think they got it wrong