Scotland's publicly funded £1m-a-month emergency ferry has been left holed up in Ayr for nearly a week as safety issues have meant it cannot use one of the nation's ports while question marks exist on its suitability on others.

The Herald can reveal that new trials are being conducted on MV Alfred's suitability to be used in the port of Troon - following problems over operating from Ardrossan to serve one of Scotland's busiest routes to Arran.

In October it was discovered it could not provide lifeline services on another of ferry operator CalMac's busiest routes - as it was unable to fit in the port of Stornoway on the Isle of Lewis.

MV Alfred had been providing support on services to and from Arran till last Thursday when the harbour authority ordered all users to cease operations from the Irish Berth. It was expected to be out of action until at least January 24.

But the berth remains out of action with no definitive date over when or if it will be back in service. It remains out of action as inspection results are not yet available.

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MV Alfred, as it is unable to use the alternative Ardrossan berth, had ended up sent to Ayr.

Peel Ports, which owns the harbour, says they expect results over the Irish Berth to be available by the end of this month at which time a decision will be taken over the continued operation of the berth.

It has emerged that since Thursday, MV Alfred has had to lay up in Ayr.

And yesterday, trials were taking place to see if the vessel could operate services from Troon.

But CalMac have warned user groups that any service that might be run may have to be "restricted to certain vehicle types and will not be possible until ramp modifications have been carried out".

On top of that, user groups were told that Troon is not yet available for full passenger and vehicle service due to what is described by CalMac as "fire compliance issues".

The Scottish Government-owned ferry operator said that they were exploring "temporary solutions to overcome this issue".

In the meantime, Arran has to rely on a one-ferry service provided by ageing 40-year-old MV Isle of Arran - which itself had been out of action since Monday due to engine problems and returned on Wednesday after sea trials.

It comes as CalMac warned earlier this week of weeks of disruption as some of it ageing fleet have been sidelined due to a new wave of technical problems.

MV Caledonian Isles, MV Coruisk and MV Isle of Mull are set to be held up in overhaul for longer than planned for essential repairs. CalMac said it was working with partners to finalise a timetable of repairs for each vessel.

The Herald: Stricken vessels: MV Isle of Mull with (inset) MV Coruisk and MV Caledonian Isles

User groups have been told that that MV Isle of Mull has been hit with a new wave of rust.  And MV Caledonian Isles is also needing steelwork.

One ferry user group official said it was further proof that there was not enough knowledge of how the emergency ferry could be used in advance of the charter.

"It should be said that we have desperately needed extra support while we wait for new ferries to be built and put into service but to bring in a ferry without a clear view on whether it is suitable for some of our ports is bewildering.

"The chickens are coming home to roost now as we have a number of vessels that are sidelined as faults are found in dry dock while the ferry merry-go-round is in full swing."

It comes after the Herald revealed that moves to upgrade Ardrossan to allow it to take much delayed and over-budget ferries are in limbo and will not be ready when they set sail with costs expected to have doubled.

CalMac has already been planning to use Troon rather than Ardrossan for the two ferries that will serve Arran. That was when it was hoped that the first of the vessels would be ready for passengers in the Spring of last year.

There are understood to have been issues over how the cost – which in 2022 was estimated at £40m – would be divided between the Scottish Government quango Transport Scotland, the harbour owner Peel Ports and North Ayrshire Council.

And the Ardrossan Steering Group was told by Transport Scotland officials that as of May, the estimated cost is thought to have doubled which it is said was "reflective of the market conditions within the construction industry".

The Herald: Ardrossan ferry terminal

However, there have since been further discussions amongst funding partners over the required project scope – which could set the costs even higher.

The improvement works, as of November, did not include the replacement or strengthening of the Winton Pier and stricken Irish Berth which in certain wind conditions ferries use to manoeuvre out of the harbour.

According to one letter from the Scottish Government to the Ardrossan Harbour Task Force, made up of the potential funding partners and co-ordinated by the Scottish Government's Transport Scotland agency, concerns about the integrity of the quay walls have been heightened following recent structural failures to parts.

The walls were expected to provide support to an LNG tank, which would be used to help fuel the vessels.

The cost of MV Alfred to operate for 15 months as CalMac's ageing fleet creeks is estimated to be at £15m.

MV Alfred was initially brought in by the Scottish Government at a cost of £9m for nine months to help support the CalMac network after a series of breakdowns of the ageing fleet.

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A further agreement was reached on similar terms to operate throughout the Clyde and Hebrides Ferry Services network for an additional six months up to the end of July 2024.

It was due to join the fleet from April 18 last year but was delayed because of Pentland Ferries had issues with another vessel in its fleet - meaning it had to hold the vessel back.

Pentland Ferries staff, who operate services on behalf of Scottish Government-owned CalMac, bought MV Alfred for £14m in 2019 to operate between Caithness and Orkney.

It was built in Vietnam and can accommodate 430 passengers and 98 cars, or 54 cars and 12 articulated vehicles/coaches.

At the time it was described as the "most environmentally-friendly ferry in Scotland".

Under charter, all crew is provided by Pentland Ferries who will be responsible for delivery of service and the operational, technical and safety management of the vessel, including maintenance, repair, overhaul and provision of crew throughout the charter period.

Three years ago a deal to buy a vessel similar in design to MV Alfred for £9m collapsed after the Scottish Government-owned procuring and ferry owning company Caledonian Maritime Assets Ltd (CMAL) demanded a foreign firm pay up to £100,000 to pay for modifications that would allow it to gain UK maritime approval for it.

A Transport Scotland spokesman said: “The extended charter of the MV Alfred to the CalMac fleet has been welcomed and has provided important and valuable resilience during annual overhaul and service disruptions on a number of routes on different occasions.

“We have always been clear that the MV Alfred can only operate in certain harbours, but it has also allowed other vessels to be moved around the network to provide vital connectivity during disruption. For example, she provided coverage in the fleet during the outage of the MV Hebridean Isles last year and has also supported Sound of Harris routes with an alternative service between Tarbert and Lochmaddy.

“We understand the frustration from stakeholders and communities in Ardrossan, Arran and Campbeltown around delays to upgrading Ardrossan Harbour, but it is essential we have a refreshed business case to support this project in light of significant changes to the original plans, which look to improve the resilience of the service and better accommodate new vessels that are due to enter service in the future. This includes work on the Irish Berth which has seen corrosion identified in recent days, and we are in contact with Peel Ports as owners and harbour authority at Ardrossan about that issue and the impact it has."

A Peel Ports Group spokesman said: “As part of routine maintenance, a temporary pause to service has been put in place at Ardrossan Harbour’s Irish berth to allow further dive inspections to take place. We expect the outcome of these inspections to be available by the end of the month, at which time we will take a decision on the continued operation of the berth.

“The main Arran berth is fully operational, however recent extreme weather conditions have further impacted services. We apologise for any inconvenience caused to users of the ferry service at this time, however safety must always be our priority.”