Moray Council has insisted its Selkie dredger continues to be fit for purpose despite its excavator needing a new engine less than five years after launch.
The vessel has only recently returned to sea after months berthed in Buckie following the breakdown.
Senior officials have suggested corrosion from the salty sea air was to blame – while stressing they had learned lessons to stop it happening again.
Concerns Selkie dredger can’t handle marine environment on Moray coast
However, concerns have been raised about why the Selkie dredger’s engine has broken down so soon after launching into the Moray Firth.
A £59,000 repair job was needed to allow the vessel to return to sea.
Keith and Cullen councillor Donald Gatt said: “It’s kind of surprising from the outside because you would expect it to be designed for operation in the maritime environment.”
Moray Council transportation manager Nicola Moss explained steps had been taken to ensure the excavator was covered as much as possible to prevent exposure to sea spray.
She added: “There has been a little bit of talk that potentially more modern plants are less suited to the marine environment than more old fashioned machinery.”
Priorities for the Selkie now it has returned to sea following its engine replacement include dredging a sand bank near the entrance of Burghead harbour, the entrance channel at Buckie and operations at other Moray ports including Findochty, Hopeman and Cullen.