The two CalMac ferries being built at Ferguson Marine shipyard in Port Glasgow are "obsolete" and will spew out "poisonous gases", according to the former owner of the site.
Jim McColl took aim at the Scottish Government over its handling of the ferries fiasco during an evidence session of the Public Audit Committee at Holyrood.
McColl and the Scottish National Party administration have clashed since an Audit Scotland report published earlier this year revealing that two new vessels built at the yard will now cost around £250m - more than double their original price - and be around four years late.
Both sides have blamed one another, with McColl saying contracts were given "for political purposes", while First Minister Nicola Sturgeon and her ministers refuting suggestions that there was a rush to get things ready for a party conference at the time.
During the committee hearing, McColl was asked about the vessels that are currently being built at the yard.
He told MSPs that they are "not green vehicles", adding: "They shouldn't have LNG (liquefied natural gas) vessels there, CalMac didn't want them, Luke van Beek [a former adviser to the Scottish Government on shipbuilding] gave evidence about speaking to the chief executive at the time of CalMac.
"There are no bunkering arrangements in place for LNG, and it's going to cost a lot of money to put that in place; they'd have to ship tankers up from the Isle of Grain.
"They can't do that, and they are now obsolete technology," McColl continued. "There are a couple of papers recently, one from a Norwegian minister, saying that they wouldn't be buying any more LNG fuel vessels, and an industry report saying that the emissions from LNG vessels are 80% more toxic than diesel fumes and they all have to be eliminated.
"The government had been advised by the Ferry Advisory Committee, which was wound up, but before it was wound up, the two experts on it wrote a final report - they'll tell you that they are wrongly spec'd."
During the session, McColl said that it was "absolutely nonsense" for the government to suggest that anything negative would have happened to the yard had the contract for the ferries not been awarded.
He also criticised the Scottish Government’s turnaround director Tim Hair for removing senior officials and changing specifications in a way that contributed to cost overruns, adding that he was given assurances that his alternative to a full builder's guarantee was acceptable by the then Transport Minister Derek Mackay.
Elsewhere, McColl said that a mistake that added £8.7m to the cost of the ferries was the fault of government-appointed management.
In February, it emerged that hundreds of cables already installed on Glen Sannox were too short to reach control panels, but he told MSPs that the problem arose because the position of equipment was changed.
McColl, who rescued the shipyard from administration in 2014, blamed the government's ferries procurement agency Caledonian Maritime Assets Limited (CMAL) for most of the problems with the building of the ships, and stated that the yard's nationalisation of in 2019 had been a "catastrophe".
Public Audit Committee convener Richard Leonard said that the session provided useful context for the next meeting with the chief executive of CMAL, scheduled for 30 June.
"In the meantime, the committee has agreed to write to the Scottish Government and administrators involved in the sale of Ferguson Marine to gain further information about the records.
"We also await receipt of written evidence from the former chief executive of Transport Scotland, David Middleton; the former director general for enterprise, environment and innovation at the Scottish Government, Graeme Dickson; and the former transport minister Derek Mackay."
Following the committee, Conservative shadow transport minister Graham Simpson said: "Jim McColl’s testimony completely undermines the SNP’s sole defence for the entire ferries fiasco, namely that Ferguson Marine would have folded and hundreds of jobs would have been lost had they failed to award the yard the contract.
"He was adamant that this was not the case, and that he now wishes the yard had never landed the fateful Scottish Government contract because it would have prospered without it and, ultimately, been spared ‘catastrophic’ nationalisation.
"His evidence was a damning indictment of the SNP’s role in a scandal that has betrayed both our island communities and taxpayers."
Meanwhile, Scottish Liberal Democrat economy spokesperson Willie Rennie said: "This evidence suggests that the government’s own turnaround guru Tim Hair gutted senior staff and allowed specifications to change in ways that racked up huge bills.
"We need to see NDAs waived so that staff who are in the know can speak out, unless we get to the bottom of this sorry saga, businesses will begin to think twice before getting into bed with the Scottish Government.
"We also need a full public inquiry and a commitment from ministers to offer their resignation if there are more delays and cost overruns."
The Scottish Government has been contacted for comment.
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