Tiree ferry terminal is likely to close on February 28 for three weeks to allow the linkspan to be replaced.
It will mean no vehicle passengers can travel to the Argyll island, though a freight service will be operated during the work period.
The linkspan was originally due to be out of operation from Monday, February 24 until Tuesday, March 17.
However, Caledonian Maritime Assets Ltd (CMAL) and CalMac decided to delay the closure to allow the delivery of essential goods to the island.
Poor weather conditions in recent weeks had impacted deliveries.
Instead, the terminal will close on Friday, subject to weather conditions.
CalMac will continue to monitor the weather and the transportation of essential goods to ensure all lifeline supplies are delivered prior to the closure.
Those with a requirement to ship essential goods before the closure are being asked to call the Oban port office on 01631 700 506.
Ramsay Muirhead, director of port infrastructure and planning at CMAL, said: “Hopefully, with a more settled weather forecast, the project will get underway on Friday, with the same three-week completion timescale.”
A further update will be provided by CMAL every week, beginning on Monday.
Vehicles will be unable to travel to the island during the linkspan closure.
CalMac will operate a passenger only service, supplemented by a third-party freight vessel service.