A fourth of ferry operator CalMac's lifeline vessels has become sidelined to passengers due to problems with a gearbox.

According to an official schedule, the overhaul to 20-year-old MV Loch Portain was supposed to finish on Tuesday.

But it has been confirmed the vessel which was operating services linking the island of Berneray with Leverburgh on the Isle of Harris will be out of action until March 1.

It comes as three other vessels remain out of action to passengers having been sidelined for weeks.

The state-owned ferry operator has confirmed that delays in MV Loch Portain's appearance have come to allow a gearbox to be overhauled and redelivered to the vessel. It said weather conditions also contributed to the delay.

So the far smaller relief vessel 27-year-old MV Loch Bhrusda, which itself was delayed from its annual overhaul by over two weeks is now remaining on the Berneray to Leverburgh route. Delays in MV Loch Bhrusda's arrival had meant that a passenger only charter vessel had to be brought in for the service.

Users have been told that the MV Loch Bhrusda - which can carry only half the number of vehicles that MV Loch Portain can take - will now operate sailings on the service from next Saturday (February 25) to March 1. 

 MV Loch Portain’s had been late going in for its schedule overhaul and CalMac indicated there was a four day delay in its return from the overhaul due to the gearbox issue.  Weather conditions also contributed to the delay, a spokesman said.

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Harris residents raised concerns last summer when MV Loch Portain broke down with problems with its propulsion system leaving services on the route to Leverburgh on Harris and the island of Berneray - an important link in the Hebridean island chain - cancelled for days.

Meanwhile an overhaul to 25-year-old MV Clansman which identified newly steelwork corrosion which must be replaced, has continued to delay her return to service.

CalMac said last Friday that it was to have an impact across the network, with Arran, Mull, Islay, Coll, Tiree, Colonsay and Hebrides communities affected due to necessary changes in vessel deployment.

The Herald: Tha am MV Clansman ga càradh an-dràsta

The vessel has been due to be back in service on that Friday after moving for its annual maintenance overhaul on January 20.

CalMac then said that Clansman's return had been delayed by "a few days" to cover the emergent steel work.

But it has been confirmed that Clansman has still not returned a week later.

CalMac has told users that the veteran 34-year-old MV Lord of the Isles would be operating on services to Coll and Tiree till March 12 because of delays to the overhaul programme.

Users have already been told that there will be no services to and from Colonsay on Saturday, as well as on February 24 and March 4. And a single vessel timetable is operating to Craignure on the Isle of Mull.

Meanwhile, MV Caledonian Isles remains sidelined till at least March 1 following concerns with its main engines.

The vessel was originally withdrawn from the Ardrossan-Brodick route for annual maintenance.

According to state-owned CalMac the overhaul was due to conclude at the end of January after being in dry dock for nearly a month with more than £1m of scheduled work being done to the vessel, including engine servicing.

But the inspections uncovered further issues including damage to both engines.

The vessel, which carries 1000 passengers and 110 cars, was out for weeks just last Easter due to an engine failure.

CalMac said that routine inspections of 30-year-old MV Caledonian Isles' main engines identified concerns with crankshaft and turbocharger components that must be resolved prior to completing the overhaul, to reduce the risk of failure in service and "ensure the safety of our colleagues and customers".

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One ferry user official said: "It is enough to make you weep, really. You just cannot rely on the vessels coming out of dry dock at all because it seems that the more they look at the ferries, the more nasties they find. What I am furious about is there appears to be complete inertia about resolving this and it can be by simply bringing in other ferries from outside to support our fleet which has been criminally allowed to be run into the ground.

"This situation never appears to get resolved in the short term."

Meanwhile the lifeline service to Arran, one of the busiest on the west coast of Scotland, remains a one-vessel service with 38-year-old MV Hebridean Isles unavailable for passengers and concentrating on providing freight services.

Video: Berneray to Leverburgh on MV Loch Portain

MV Hebridean Isles first hit problems on Boxing Day and has been on and off service with bow issues while passengers to Arran were being switched to a one-boat rather than a two-boat service with the 40-year-old veteran MV Isle of Arran in operation.

MV Hebridean Isles ended up providing a freight-only service to the island four weeks ago. It is unclear when it will return to providing normal passenger services.

Concerns have previously been raised about disruption being felt across the network as the depleted ageing fleet was redeployed to try and cope with the loss of both 38-year-old MV Hebridean Isles and Caledonian Isles to passengers.

It had been expected to support services to and from Islay with the MV Isle of Arran for an overhaul for two months from February 5 as part of the rejigging of the network through the state-owned service's programme to improve fleet sustainability through its overhaul programme.

But neither vessel was able to make it.

CalMac have have already cut the Islay service to a single vessel and drafted in MV Finlaggan until February 16. Now it has emerged that due to the overhaul issues it will now remain till March 5.

It was supposed to provide services for a month from February 6 to and from North Uist through a temporary timetable brought in by the closure of Skye's Uig harbour for essential repairs.

MV Isle of Arran has been serving Arran for weeks on its own because of the issues with Hebridean Isles, cutting the number of available vehicle spaces to about half. It was  expected to remain solo till at least February 16. That has now been extended to February 28.

The Herald:

Before the new year a third of the 14 major vessels 35-year-old MV Isle of Mull was found to have suffered hull rust issues and subsequently engine issues and was sidelined for weeks.

It was to emerge from its month-long annual overhaul on December 23 but remained out of action nearly three weeks later.

Some 18 of of CalMac's 35 working ferries deployed across Scotland are now over 25 years old.

Two new lifeline ferries Glen Sannox and Hull 802 were due online in the first half of 2018 when Ferguson Marine was under the control of tycoon Jim McColl, with one intitially to serve Arran and the other to serve the Skye triangle routes to North Uist and Harris, but they are at least five years late. The last estimates suggested the costs of delivery were due to soaring from £97m.

A Transport Scotland spokesman said: “As well as weather related challenges there have been ongoing technical issues with vessels resulting in cancellation of sailings and delays to scheduled annual overhaul plans. Ferry operators prioritise food and essential supplies during disruption and, as part of the local resilience partnership, they remain in contact with local communities and hauliers.

“In 2022 there were over 170,000 scheduled sailings across the CHFS network and 11,301, around 6.6%, of these were cancelled.  Over half of the cancelled sailings were due to weather related issues. Around 16% of the cancelled sailings (1.1% of the total scheduled sailings) were due to technical issues with vessels.

“We recognise that every cancelled sailing can have a significant impact and continue to work with operators and CMAL to improve reliability and resilience across our networks. Regrettably there are communities who have been more greatly impacted than these average figures show and we fully recognise the need to improve reliability and confidence in services. Should there be cancellations to CalMac services due to weather or technical issues then a full refund will be provided to the customer.

“We share the desires of island communities for sustainable and effective ferry services and look forward to continuing our constructive engagement with them on future services and vessel replacements.

“As part of the forthcoming Islands Connectivity Plan, we are setting out our draft Long-Term Plan for Vessels and Ports which the Project Neptune report called for and islanders need to see.”