The Isle of Man's main ferry will be out of action for longer than anticipated while "essential works" are carried out.
The island's ferry operator said "further necessary repairs" were needed after the Manxman entered drydock last week for scheduled maintenance.
The vessel has been replaced on the Douglas-Heysham route by former flagship ferry Ben-my-Chree, the Isle of Man Steam Packet Company said.
Back-up freight vessel MV Arrow is also set to return to the island while the Manxman is out of action. The operator said it was "reviewing its operational plans to minimise disruption" to passengers wherever possible.
The Ben-my-Chree had been due to take over as sole operator on the firm's Larne route from Friday.
That sailing will now be carried out by the fast craft Manannan.
The back-up passenger vessel itself has suffered "technical issues" in recent days, leading to cancellations on the Heysham route on Sunday and Tuesday.
The Manxman had been due to return to service on Wednesday but no revised date has yet been confirmed by the Steam Packet.
Managing director Brian Thomson said while it was recognised it would be "frustrating" for passengers, extending the ferry's period in drydock was "necessary for safety and operational reliability".
He added: "Completing these additional works now will ensure the vessel can continue to provide a reliable and dependable service in the years ahead."
The government-owned ferry firm runs daily sailings between the island and Lancashire and Liverpool, along with regular sailings to Larne in Northern Ireland.
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