Temporary 'Yokohama' fenders were delivered to Rothesay pier on Tuesday morning, with installation due to take place on Wednesday and berthing trials at the old linkspan berth, using one of the two Rothesay vessels, pencilled in for later in the week.

But CalMac's regional manager for Bute, Brian Fulton, told us that before those trials can take place Balfour Beatty, the contractor for the pier work, has to install bollards to hold the ferries'ropes in place - and it's likely to be the end of the week before these bollards are ready.

Since January 14, building work to reinstate the berth, where the old side-loading vehicle linkspan was formerly located, has forced one of the two Rothesay ferries to berth overnight in Gourock, with the loss of one evening crossing from Wemyss Bay every day as a result.

From Monday to Friday the 1815 sailing from Rothesay has been diverted to Gourock as a result of the work; on Fridays the 1945 from Rothesay is also cancelled, and on Saturday and Sunday the 1900 from Rothesay sails to Gourock.

In the other direction, the 1900 sailing from Wemyss Bay is cancelled on Mondays to Fridays, along with the 2040 departure on Fridays and the 1945 on Saturdays and Sundays.

The disruption caused by the work at the pier has been partly responsible for a sharp drop in CalMac's performance statistics for the year so far, which Mr Fulton reported at a meeting this week of the cross-community Bute Beyond 2000 steering group.

Until last week there had been 295 cancelled sailings on the Rothesay route during 2008, though most of those occurred on the five days in February when there was no service at all because of the strike action by Argyll and Bute Council pier hands in their dispute with the authority over the proposed Single Status settlement.

The pier building work, Mr Fulton said, was responsible for 48 cancelled sailings and for most of the 55 diversions so far this year.

The Isle of Bute Jazz festival begins on Thursday evening and runs throughout the holiday weekend until Monday afternoon.