ONE of Scotland's lifeline ferries is expected to be out of action for at least ten days after suffering engine problems for the second time in three months.

CalMac services were cancelled between the mainland and the Isle of Bute while the route has been cut to a single rather than a dual ferry service, after new engine problems with 16-year-old MV Bute surfaced at the weekend.

The state-controlled ferry operator has advised passengers to avoid using cars on the service and suggested a 28 mile detour to use another route The vessel, which can carry 450 passengers and 60 cars had only just returned to action last week after an annual overhaul was delayed.

In August, another engine problem led to cancellations of sailings between Wemyss Bay and Rothesay with the possiblility of further disruption while repairs were attempted.

READ MORE: 'Scandal': Ministers 'ignored' 11-year-old CalMac warning about perilous state of Scotland's lifeline ferries

Passengers have been advised to travel if possible "by foot" as the smaller MV Coruisk, which can carry 250 passengers and 40 cars has been brought in as a relief vessel.

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But it is due to go over its annual overhaul on Monday. It is expected that MV Argyle, which like Bute can carry 450 passengers, 60 cars is due to take MV Coruisk's place after she comes out of her overhaul. The vessel is due out on Friday.

One Argyll and Bute councillor Liz McCabe said she had had contact over the weekend from CalMac to say they have not been able to get to the root cause of damage to the engine on MV Bute and that there will have to have a one vehicle service for "some time".

She said she was told it will be out of service until December 3 at the earliest.

MV Argyle was currently in dry dock at Gourock until November 30, however when she comes out of dry dock and MV Coruisk will go in.

"It looks like we will have one vehicle for some time which is absolutely shocking and just not good enough," she said.

Services were cancelled on Friday morning when problems with one of the main engines of Bute first emerged on Thursday night.

READ MORE: Revealed: Execs extended working life of Scotland's beleaguered ferry fleet by 15 years in 'ruse'

CalMac withdrew the vessel from Saturday because as the problems continued.

As a new one-vessel was put into operation, CalMac "strongly advised" passengers that as vehicle space would be "very limited" that "where possible to travel by foot".

The state-controlled ferry operator advised that if travel with a vehicle is necessary passengers should "please consider" travelling through an alternative Bute route from Colintraive to Rhubodach.

That would involve a 28 mile detour from Wemyss Bay. Rhubodach is eight miles away from Rothesay.

It is the latest in a summer of issues with breakdowns and Covid issues involving Scotland's ageing ferry fleet.

Transport minister Graeme Dey has said attempts were being made to ease the ferry crisis by purchasing another ferry.

The breakdown in April of Scotland's biggest publicly-run ferry MV Loch Seaforth, which operates on the Stornoway to Ullapool route, caused disruption across the islands network for seven weeks.

Islanders from Arran to Islay have lodged complaints to ministers about disruption and cancellations to services as the ageing Scottish ferry fleet falters.

While industry experts agree the working life of the ferries is 25 years, 14 of the 33-strong ferry fleet run is older than that, with eight, including Hebridean Isles, past their 30th birthday.

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Glen Sannox in dock last year.

The delivery of new island ferries MV Glen Sannox and Hull 802, still languishing in Ferguson Marine shipyard, which were due online in the first half of 2018, was found to be over four years late with costs doubling to over £200m.

Tommy Gore, Clyde area operations manager for CalMac, said: “MV Bute has been taken off service for further investigation into the cause of an engine fault, and we have been advised that this work may take up to 10 days. A single vessel will operate between Rothesay and Wemyss Bay in the meantime. We apologise for any inconvenience that this is causing to passengers.”