CMI Offshore told Scotland on Sunday that the yard – which is building two massively late and over-budget CalMac ferries – had “extremely low productivity and quality control” and said much of the work on the barge had to be redone.
One maritime source said: "If they can't build a steel box [the barge], they can't build a ferry."
It is understood that CMI was so frustrated with the Port Glasgow yard that it set up a mini shipyard at a dock in Glasgow to continue work on the late-running barge, and found half the bottom welds were defective.
Scottish Labour descried the news as “utterly shocking”.
Construction of the 55m-long barge Argymak, built for the Caspian Sea, started in 2018, two years after work began on Glen Sannox and unnamed sister ferry (hull 802), ordered for CalMac, which are now due to be completed five years late in 2023, at a cost of some £240m, two and a half times the original price.
When the barge left Port Glasgow in June 2020, nearly a year after the yard was rescued from administration by a Scottish Government takeover, turnaround director Tim Hair said the launch represented “a key milestone in the recovery of Ferguson Marine”.
However, Richard Keisner, managing director of Mangistau ACV Solutions, part of CMI, said: “Our experience at the Ferguson shipyard was affected by a shortage of direct labour throughout, which seemed to move from one vessel under construction to another, which was combined with extremely low productivity and quality control.
“Much of the work had to be redone or completed at other shipyards following Ferguson’s bankruptcy, particularly given that the new state-owned enterprise and its management were unwilling to commit to a certain time or cost to complete their contract.
“In retrospect, we would say that any confidence that we placed in the ability of the yard, its management or workforce to build vessels was totally misplaced.”
A maritime source said two fish farm work boats for Mull, built at the yard at the same time, did not have “any major deficiencies”.
However, they were also finished late and the three vessels lost the yard nearly £8m.
Scottish Labour said the revelation was “just another example of the SNP’s continuing Ferguson fiasco”, which would do nothing to attract new customers.
Transport spokesperson Colin Smyth said: “The Scottish Government claims its actions have always been about safeguarding jobs.
"But reports of firms having to tow their barges away from the yard to be completed elsewhere are utterly shocking and show that things have gone from bad to worse at Ferguson.
"Instead of ducking responsibility for decisions, ministers, in particular Nicola Sturgeon, need to get a grip and put in place a proper strategy to turn the yard around so we don't keep getting examples like this.
"Firms need to have confidence that when they place an order, it is delivered on time, on budget and is fit for purpose.
"Workers at the yard, communities waiting for their ferries, businesses who are losing faith in placing orders and Scottish taxpayers deserve better than this SNP shambles."
Scottish Conservatives transport spokesperson Graham Simpson said: “This firm has clearly had a rotten experience at the yard, both prior to and since nationalisation.
“The yard can't afford to get a reputation for poor work, so I hope the new management can turn things around.
“They are going to have to win new orders before the ill-fated ferries are complete so they can have a steady pipeline of work.”
A spokesperson for Ferguson Marine (Port Glasgow) said: “It is important to recognise the majority of the experience described by this customer was under the previous management, before administration and public ownership.
“There is acknowledgement of the challenges experienced by the shipyard in the post-administration period, exacerbated by the Covid pandemic.
"While significant operational improvements have been made in the past two years, we know further changes are needed and are being implemented.
"Our new chief executive, who joined in February, has already made changes to project management, and the new programmes for the dual fuel ferries are making a difference.
"The approach to completing hull 802 will be more reflective of Ferguson Marine’s historical reputation for quality shipbuilding.”