"Complex repairs" needed for a ferry that hit the seabed off Guernsey mean it will be out of service until 26 August.
The Commodore Clipper was damaged while on a journey between Portsmouth and Guernsey on 14 July.
Its loss on the route between the UK and the Channel Islands has led to delays to post and freight deliveries, leaving some shops short of stock.
James Fulford, CEO of Condor Ferries, said a replacement was being worked on.
He said: "We are completely committed to keeping our islands connected and supplied via the lifeline service which we provide.
"Our staff are working around the clock both to minimise disruption for our customers and to put in place the most robust contingency arrangements as our top priority.
"Our fleet management team is working around the clock to secure the very best freight charter solution as early as we can. I hope to announce this imminently."
Passengers and vehicles are being transferred to the company's high speed ferries and extra services are being put on to deal with the increased number of passengers on these services.
The freight-only vessel the Commodore Goodwill is operating extra sailings and the ferry company said all food and priority items continued to be shipped on the day while other items were being delayed by two or three days.
Mr Fulford said it had not been possible to secure a direct replacement for the Commodore Clipper, which provided both passenger and freight services.
He said: "Operating ships from the Channel Islands presents particular challenges in terms of the sea conditions and the characteristics of the historic ports.
"This means there are very few ships which are compatible with our islands' needs."
How the damage was sustained is being investigated by the Marine Accident Investigation Branch.