The MV Loch Shira ferry service between Largs and Cumbrae is offline following a fire in the engine room this afternoon.
An emergency centre has been set up in Millport for stranded people.
In a letter to Cumbrae Ferry Users Group. CalMac Network Resilience manager Tommy Gore said: "Unfortunately MV Loch Shira has experienced a fire in her engine room and has had to return to Largs.
"The replacement ferry Mv Loch Riddon will be able to operate until approximately 10pm tonight so we will clear as much of the backlog as possible. "People are being told to travel as foot passengers if they absolutely have to get off the island tonight.
"The main priority is daytrippers as they obviously don't have accommodation for the night on the island.
"MV Loch Shira repairs are progressing well - current advice is that the Vessel should be available for service tomorrow morning, potentially even from start of service."
The Garrison cafe in Millport has been open with hot drinks and access to toilets for stranded passengers.
Millport based councillor Todd Ferguson said: "Riddon has been working to clear the backlogs in Largs and Cumbrae.
"The local response from residents and businesses has been first class as usual.
"A special wee island community that rallies together when these issues arise.
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