As the Buteman went to press earlier this week Clydefast was in the middle of a three-day trial 'service' between the SECC and Dunoon which it hoped would test the suitability of this striking mode of transport.

The move follows hard on the heels of similar tests in the Forth for Stagecoach last year.

While there is no guarantee that Clydefast's trial will lead to a permanent presence on the Clyde and local islands, the group behind the scheme has pledged to include Rothesay on the timetables of any future service if it does go ahead.

And if the Clydefast scheme wins over officials and the local authorities, the likelihood of a return of hovercrafts to Rothesay on passenger service for the first time since the 1960s could become a very real possibility.

Speaking at the launch of the trial Alistair Macleod, the chief executive of Clydefast said: "We are very excited about the test and are indebted to Glasgow City Council, Riverside Inverclyde and Strathclyde Partnership for Transport (SPT) for making the trial possible.

"It will hopefully demonstrate the potential for a permanent hovercraft operation to be brought to the Clyde.

"The service will be fast - for example a service from Dunoon to Glasgow will reach the city centre in 52 minutes, over 20 minutes quicker than the present journey time of an hour and a quarter (by train and ferry).

"Rothesay will be included in a permanent operation which would add a further 15 minutes to the journey," he added.

A permanent service would operate to and from Glasgow Broomielaw, Braehead, Greenock, Dunoon and Rothesay and would be able to carry up to 130 passengers.

The craft can also travel in open seas at speed of up to 40 knots, although the river speed would be reduced to a level acceptable to the Harbourmaster.

Bute councillor Len Scoullar is pleased with the news, and has spoken of his hope that it gets the greenlight by officials.

"This is an exciting development and I hope it is successful because any addition to our service, especially a high speed one, would be most welcome to people on Bute," he said.

The hovercraft carrying out this week's trial is a Griffon 2000TD. The trial wasn't open to fare paying passengers, unlike the Forth trials for Stagecoach.

Instead the trials were being held to allow the Clydeport Harbourmaster to assess the impact that a regular river operation would have on other river users. However, Clydefast are confident that the hovercraft would generate little wash at speed, while also offering a fast service.

The trial also offered the chance for interested investors and local authorities to experience the service.

"We're delighted to support this trial," said Ron Culey, chief executive of SPT. "Development of the Clyde as an additional transport channel helps the ongoing regeneration of the area.

"By encouraging varied and fun ways to travel along the river, we can continue to make Glasgow a vibrant location for people to visit," he added.