An assessment is ongoing over whether military help is the solution for Highland Council’s Corran Ferry.
There has not been a car ferry on the five-minute crossing of Loch Linnhe in Lochaber for three weeks due to issues with the main vessel and a relief boat.
It is the busiest single-vessel ferry route in Scotland and carries more than 270,000 cars each year.
The Ministry of Defence (MoD) has agreed to look at what assistance it might be able to offer.
A military team has visited the area, but Highland Council said discussions with the MoD remained ongoing.
Ardgour Community Council, which represents residents in an area affected by the disruption, said the situation was having a significant impact on businesses.
Currently passenger-only services are available.
Highland Council said it had received an interim report from the MoD after its request for an assessment of the MoD’s capability to assist with vehicle transportation.
A spokeswoman said: “The council and MoD are engaging on a number of points arising from the report in order to determine whether requesting a Maca (Military Aid to Civil Authorities) would deliver the assistance that’s needed.
“A further update will follow as soon as information is available.”
The Scottish government said it was ready to assist Highland Council with a Maca request when needed.
A spokesman said: “We understand that Highland Council are currently working with the Ministry of Defence to explore options for military support.
“Once those discussions are complete, it will be for Highland Council to decide whether to proceed with a request for military aid, at which point they would request support from the Scottish government.”
The MoD declined to comment.
Two weeks’ ago, SNP MP Ian Blackford said an “agreement in principle” had been reached for military help on the route.
At the time he said he hoped a replacement service could be in place “in coming days”.
Ardgour Community Council said the passenger-only service and improvements to the area’s A861 road were welcome.
But a spokesperson added: “We are frustrated about the ongoing lack of information about the return of MV Corran or an alternative vehicle service for the narrows.
“Ardgour Community Council urges every Highland Councillor and MSP to put themselves in the shoes of our community where everyday they need to figure out the complicated logistics of how they get to their place of work and back, how they attend medical appointments, pick up prescriptions, do their shopping, or how to minimise the losses to their business.”
Electric ferries
People living in Fort William, Ardgour, Sunart, Ardnamurchan, Moidart, Morar, Morvern and the Isle of Mull, as well as tourists, are among those who regularly use the ferry.
When the service is unavailable due to bad weather or breakdowns it is a 42-mile detour to get from Corran to Ardgour, but diversions can involve journeys of up to 86 miles, depending on where people are headed for.
In February, council officials told Holyrood’s transport committee the service was at breaking point.
MSPs heard the Corran Ferry’s two aging vessels need to be replaced within the next three to four years.
The boats – the 23-year-old MV Corran and 47-year-old Maid of Glencoul – are also too small to cope with demand from locals and visitors.
Highland Council plans to run two new electric ferries on its service in Lochaber, but needs to find £62m to pay for them.