Buses are being brought in to support lifeline services on one of Scotland's busiest ferry routes which is suffering a new wave of disruption after a fourth day of safety issues at a port.

After disruption on Tuesday which meant the cancellation of six services caused by what is thought be a sinkhole at an Ardrossan pier, CalMac used a different berth awaiting a safety assurance from the harbour owner Peel Ports. All foot passengers were told they were required to board and disembark via a car deck.

On Friday morning seven more services on the Ardrossan to Arran and the Ardrossan to Campbeltown routes have had to be cancelled as investigations continue with decisions yet to be made about afternoon sailings.

At least two other services to and from Arran are having to be diverted to Gourock because of the Ardrossan issues.

Buses were arranged to allow foot passengers to connect between Ardrossan & Gourock on Friday morning.

Because of the issues with the Ardrossan berth, one ferry has had to berth overnight in Brodick, meaning the 7am service from Ardrossan was cancelled.

As weather conditions were not allowing a service to a different Ardrossan berth, the 8.20am from Brodick was diverting to Gourock.

And the 9.45am service from Ardrossan has been delayed to 11.10am and was to leave Gourock instead.

The 11:05am and 12.30pm service from Brodick and the 11.05am,  12:30pm and 1.50pm service from Ardrossan are cancelled.

Further information is expected over afternoon Arran sailings.

HeraldScotland:

The 7.35am service from Campbeltown to Ardrossan was also cancelled because of the safety problems with a decision yet to be made about the return journey at 6.40pm.

Users have been advised there will be no standby option for vehicle traffic at Gourock as space was said to be "very limited". CalMac advised people to only travel by vehicle if there is a confirmed booking and that there is no issues with foot passenger capacity.

Users have been told: "Due to a safety issue with the Arran berth at Ardrossan, we are currently unable to use it. While we await assurances from harbour owner Peel Ports that the Arran berth is safe to use, sailings are operating to the Irish berth in Ardrossan.

"As a result, all foot passengers will be required to board and disembark via the car deck.

"As we are unable to use the Irish berth at Ardrossan in certain weather conditions, some sailings may be required to divert to Gourock."

A separate update for users travelling between Ardrossan and Campbeltown said: "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."

Peel Ports Clydeport have been approached for comment.

It said on Tuesday that they had launched a probe into the issues at Winton Pier and that access has been restricted.

In a brief statement the firm said: “Peel Ports staff and specialist engineers have examined the unused Winton Pier and a decision has been taken to secure it, while further investigations are ongoing.”

Two long-awaited lifeline ferries to serve Scotland's island communities have been delayed by at least five years, while the costs are expected to rise by at least two-and-a-half times the contract price of £97m.

One of the ferries, MV Glenn Sannox - which is destined for the Arran-Ardrossan route was due to enter service in the summer of 2018.