THE lightweight foot passenger-only boats which replaced robust car ferries on CalMac's Gourock-Dunoon route have racked up more than 11,000 cancelled sailings since coming into service.

Weather-related abandonments on the crossing accounted for as much as 94 per cent of total cancellations in one year and more than 90 per cent in another, according to official figures held by Scotland's national ferries operator.

Meanwhile, there is still no date fixed for when promised new vessels to supersede the second-hand MVs Argyll Flyer and Ali Cat — whose total cancellations equate to 100-a-month during their nine-plus years of operation — will materialise.

At 172 and 73 gross tons respectively, Argyll Flyer and Ali Cat are up to 776 tons lighter than the 849-tonner MVs Juno, Jupiter and Saturn car ferries which plied the route until June 2011.

A Freedom of Information request by the Telegraph has revealed that the current vessels have suffered 11,128 cancellations from June 29 that year until October 30 this year — currently the latest date for audited figures for the service.

Abandoned sailings due to weather account for 73.3 per cent of all cancelled sailings during the full nine years and four months period — or 8,157 crossings.

CalMac has had to resort to a replacement bus service which relies on the Western Ferries service between McInroy's Point and Hunters Quay — adding to passenger journey times — during periods of weather disruption.

A total of 20 per cent of cancellations have been down to technical breakdowns and 6.6 per cent have been listed by CalMac as for 'other' reasons.

It is understood that concept designs are to be drawn up for new passenger-only ferries to replace Flyer and Ali Cat, with a naval architect to be announced shortly, according to Transport Scotland.

But there is no indication when the vessels — costing £6m each — will be built or enter service.

Caledonian Maritime Assets Ltd (CMAL), the Scottish Government quango responsible for vessel procurement, is still wrestling with the costly backlog caused by the ferries fiasco at Ferguson's shipyard in Port Glasgow.

In a recent interview, CMAL boss Kevin Hobbs said the delays in delivering two new dual-fuel ferries for CalMac — which were the subject of a Holyrood inquiry — have had an 'enormous and crushing' impact on the organisation.

Meanwhile, beleaguered passengers who have had to endure the many thousands of cancellations on the Gourock-Dunoon service will have to wait for improvements.

CMAL are looking to build a total of 19 new ships for the operator's fleet at a cost of £550m, but Mr Hobbs says the programme has been set back by two years because of the Ferguson's situation.

CalMac managing director Robbie Drummond said: "Since the Gourock-Dunoon route became passenger-only we have delivered 165,488 sailings successfully.

"6.3 per cent of scheduled sailings have been cancelled during this time.

"While we continue to invest in the existing two vessels to maintain the service, the replacement of the current vessels is a matter for Transport Scotland and CMAL to advise on."

A Transport Scotland spokesman said: "We are acutely aware of local concerns of the suitability of the vessels currently in use.

"As part of the Clyde & Hebrides Ferry Services contract, we recently invested over £2m for improvements to the existing vessels which is currently under way and which will help maintain a reliable ferry service on the route.

"In addition, we are currently taking forward the Gourock-Dunoon Vessels and Infrastructure Project.

"This major investment includes a replacement linkspan at Gourock, two new vessels for the Gourock to Dunoon ferry service and associated harbour infrastructure improvements."