Dark skies, cold temperatures and a stiff breeze made it a chilling experience for most as the flotilla of small boats, led by the new "lady of the lake," the Ena De, spread out across the lake to give passengers a chance to see some of the landslide-stabilisation measures at close quarters.
Another 300 guests joined the voyagers for the official opening on the north-east wall of the powerhouse, while about 200 people lined the top of the dam to catch a glimpse of the action.
Security guards checked the bags of spectators and some protesters wanting to get on to the dam were relieved of placards and even apples, which guards apparently feared might be thrown down at the Prime Minister and the official party during the opening.
Some protesters were also seen with climbing equipment which could have been used to abseil down the dam to disrupt the opening. Before the ceremony police stopped a few people from descending the hillside below the lookout opposite the powerhouse, keeping them on top of the hill. However, the loudhailers and sirens brought along by the anti-dam contingent ensured they got their message across to the Prime Minister.
Mr Bolger said in his address the dam represented a "genuinely enormous achievement", despite the fact the project had been difficult and expensive. The Clyde dam was now an "extremely significant long-term strategic asset" for New Zealand, which offered the country security and the potential for further growth.
Harking back to the 1982 deal with Social Credit which enabled the then National government to keep the dam project alive, Mr Bolger said the process used then was about to become "part of the fabric of political life" under MMP.
He said there were no easy answers as New Zealand looked for new power schemes - hydro dams changed the landscape, coal or gas-fired thermal stations increased harmful emissions, nuclear power had been ruled out and wind and solar generation was still at the experimental stage, although wind generation "on a modest scale" looked increasingly possible.
The Electricity Corporation's chairman, Selwyn Cushing, said there had been a time when the corporation had had to consider whether the Clyde dam project should be scrapped, after the landslide problems were discovered.
The board decided it could only proceed if there was no compromise on public safety, which was why it appointed a panel of international experts to act as independent "geological auditors" to oversee the $400 million stabilisation project.
After Mr Bolger had unveiled a plaque on the wall of the powerhouse he and his wife Joan led the official guests on a tour of the station, including a trip into the bowels of the building.
Electricorp also mounted some displays which ranged from electrical games for children to electric cars and alternative energy sources.
As the official guests headed across to Clyde for lunch at Oliver's Restaurant, the dam was opened to the public for three hours.