THE Ardrossan to Arran ferry service has hit crisis again after it was revealed that one of CalMac's oldest ships will remain out of action until at least the end of this month.

The 38-year-old MV Hebridean Isles was removed from service on February 16, having been providing freight-only cover between Arran and Troon.

The ship hasn't returned to service since - and is believed to be holed up in Ayr with a pitch propeller issue. 

The technical troubles have led CalMac to review their plans for the high summer service on the Ardrossan-Brodick route. 

A two-vessel service on the Arran run had been due to start on May 28, but it's thought that this may no longer be possible while MV Hebridean Isles remains out of service.

The ship usually serves on the Islay run, but while it's confined to port, the even older MV Isle of Arran - normally the second summer ferry between Ardrossan and Brodick - is operating on the Islay route.

The development came as CalMac announced changes to its vessel deployments across the Clyde and Hebrides routes, due to continued issues with the return of ferries to service and the delayed annual maintenance of the ageing fleet.

In a statement, CalMac said: "We are currently reviewing our deployment options after a further delay to the annual overhaul programme. We will provide an update when these are finalised. 

"Whilst we update our reservation system to reflect these changes, some sailings may be unavailable. 

"All customers with bookings affected will be contacted by us in due course. 

"Disrupting a sailing is a decision we do not take lightly because we know it will inconvenience our customers and the communities we serve. We apologise for any inconvenience caused."

Meanwhile, no date has yet been set for the entry into service of a £1m-a-month 'emergency' ferry being chartered to CalMac to try and ease the effect of the woes plaguing the state-owned firm's fleet.

MV Alfred's owners, Pentland Ferries, have said that issues found after berthing trials mean the vessel cannot yet enter service off the west coast.

Some sources suggested that the MV Alfred would be used primarily on the Ardrossan to Arran route.