An MSP is calling for reassurances after summer figures showed that one in 10 ferry journeys between Armadale and Mallaig were cancelled.
The problems started after the MV Coruisk was taken off the route and redeployed on the Oban to Mull run.
She was replaced by MV Lochinvar and MV Loch Bhrusda, which are unable to operate at low tide.
Kate Forbes MSP for Skye Lochaber and Badenoch said she was alarmed that tourist attractions in the region reported that their takings were down by tens of thousands of pounds in light of the disruption during the peak season.
She wants reassurances from CalMac and Transport Scotland that something will be done in time for next summer.
Details around the summer 2017 timetable have yet to be unveiled, but Transport Minister Humza Yousaf previously stated that the debacle must not be repeated.
Ms Forbes said: “It is no secret that the plagued Mallaig to Armadale route has been a long running saga.
“For the March to October summer season, the statistics tell the story.
“One in 10 sailings were cancelled, and only 85 per cent of scheduled sailings actually arrived on time.
“Despite an increased timetable with 660 more sailings than the previous year, only 87 more passengers travelled on the route compared to 2015.
“There were 10 per cent more cars, but a drop of 15 per cent in coaches – 350 less to be precise.”
She continued: “I firmly believe that all communities, however remote they may be, are entitled to a reliable and robust service for ferry crossings.
“To me, the only sensible solutions appear to be returning the MV Coruisk to the route it was purpose-built to serve, or recruit another vessel from elsewhere.
“Time is running out, and I believe the people of Skye and Lochaber deserve answers as soon as possible.”
A CalMac spokesman said: “We have looked exhaustively at all options to address reliability issues experienced on the Mallaig Armadale route last year taking into account the fleet resources we have available while balancing the needs of all the communities we support across the west coast. The trialling of the MV Loch Fyne is simply part of this process.”
A Transport Scotland spokesman added: “In deploying vessels, CalMac Ferries Ltd need to best balance the needs of all communities. Due consideration is given to this by the operator during timetable planning.
“Discussions between Transport Scotland and CalMac Ferries Ltd on this issue are underway.”