Figures revealed by freedom of information requests from the Scottish Liberal Democrats revealed CalMac has spent more than £850,000 in customer rights claims since 2018 – with more than a quarter paid out in the financial year up to the end of July 2022.
The claims consist of money paid out to customers for meals and accommodation, transport and compensation as a result of cancelled sailings.
The figures from April to July are almost £50,000 less than the whole of the 2021/22 financial year, where a total of £261,000 was paid out in compensation, the figures show.
And figures have increased each year – except at the height of the Covid-19 pandemic in 2020/21 – with £159,000 paid out in 2018, and £177,000 in 2019/20.
Some £51,000 was paid out in the 2020/21 financial year, according to the figure breakdown.
It comes as the extent of ferry cancellations was revealed, with figures showing a total of 7,431 cancelled sailing between January and July 2022.
The cancellations follow intense scrutiny over the construction of the MV Glen Sannox and the unnamed Hull 802 which are due next year – five years behind schedule and two-and-a-half times over-budget.
CalMac has previously said the vast majority of cancellations are a result of poor weather, however, efforts to tackle maintenance faults are underway.
Further scrutiny has emerged as Deputy First Minister John Swinney admitted to “concerns” over possible preferential treatment in awarding the delayed ferry contracts to the Ferguson Marine shipyard.
Mr Rennie said: “The bill for cancellations and compensation is soaring because the Scottish ferry network is in such a state.
“The last year has seen new levels of havoc. Aging boats are breaking down and it is having a huge impact on islanders, tourists and travellers.
“Delays in the construction of two new ferries by Ferguson Marine mean that island communities are still being put on hold by the Scottish Government.”
“We would also introduce a wider economic strategy that ensures Government projects, such as Ferguson Marine, represent value for money.”
A Transport Scotland spokesperson said: “The vast majority of CalMac ferries run on time and to schedule but breakdowns and delays are not acceptable.
“That’s why we’ve invested to provide additional capacity on the Clyde and Hebrides routes. We are also continuing to work on procuring more vessels, while the four new ferries we have ordered are being built.”
The Scottish Government has also provided more than £2 billion of support to the network since 2007 and has approved additional funding to support weather monitoring equipment.
A spokeswoman for CalMac said: “Our customers have been affected by higher than usual levels of disruption in recent years, including significant upheaval due to the Covid pandemic. This has led to an increase in the number of claims.
“Our customers are at the very heart of what we do and we aim to provide the best service we possibly can. When sailings are disrupted or cancelled, we make sure that passengers are fully aware of their rights to claim back costs they incur.”