Caledonian Maritime Assets Ltd (Cmal), which previously told builders Ferguson Marine its completion estimate was nearly a year too optimistic, said it now had a “higher degree of confidence in the project than we’ve had a long time, if not ever”.
Chief executive Kevin Hobbs told Scotland on Sunday he also agreed with the yard’s decision to postpone some work on the ferry’s sister ship, still known only as hull 802, to minimise further delays to Glen Sannox.
He said it was “critical” to get the vessel, already five years late, into service as soon as possible.
Hobbs said the ferry, which is now due to be completed in April before entering service on the main Arran route later next year, was vital in providing CalMac with a spare vessel to cover breakdowns.
He said: “All efforts must be made to get Glen Sannox out, and if that means there is a marginal delay to 802, that is the logical thing to do."
Hobbs said he had “a lot of confidence” in new Ferguson chief executive David Tydeman and believed the ferries could be delivered “very close to” current estimates.
802, earmarked for the Skye-Uist-Harris triangle, has slipped a further three months to January-March 2024.
The ferries being built in Port Glasgow are expected to total around £300m – three times over budget.
Hobbs said: "My honest feeling is unless there is a complete and utter failure of a major piece of equipment during commissioning, it can still be achieved, but if it doesn’t, you’re talking about weeks’ worth of slippages, not years.
"The difficulty is that with any major, complex projects, when it comes to commissioning the machinery, some of which has been in the vessel for a long time, if something goes wrong that can throw the whole programme out.”
Hobbs it would involve key components such as engines, rudders and propellers: "You are talking about a hive of activity during November, December and January.
"What we have seen so far with the commissioning that they have done, albeit limited, is that it is going OK.
"Broadly, the vessel is coming on in leaps and bounds."
Scottish Conservatives transport spokesperson Graham Simpson said: "I have the same confidence in David Tydeman's ability to steady the ship at Fergusons and actually deliver a couple of ferries.
"However, there remain serious questions to answer over this whole fiasco, not least is the new revelation that the whole procurement process may have been rigged in favour of a yard that was the wrong choice to build these vessels.”
Colin Smyth, his Scottish Labour counterpart, said: “Few people have any faith in anything the Scottish Government or their agency Cmal have to say about this ferry fiasco.
“For the sake of the islanders without ferries for months at a time, the taxpayers footing the bill for this scandal and the workers at Fergusons whose warnings were ignored, we can only hope there aren’t any more delays, and crucially, we need to get to the bottom of exactly what went wrong in a process that increasingly looks as if it was rigged.”