The Steam Packet has announced that the Manannan will have to operate on just three engines during the forthcoming Festival of Motorcycling.
It was hoped that repairs to a damaged crankshaft on the fastcraft could be completed before the busy period, but the company says that's not now going to be possible.
The Manannan was removed from service for one round trip earlier this week and a report from repair engineers has revealed more damage than first thought.
Steam Packet Company Chief Executive Mark Woodward says specialist machining of the engine block is required a difficult repair which can only be carried out by a small number of specialist firms. The Packet now has to wait until they are available.
To minimise inconvenience to passengers during the busy Festival period, the Steam Packet Company will be announcing details of a slightly revised schedule, on some peak days, shortly. There will also be schedule changes for afternoon and evening sailings for the post Festival of Motorcycling period.
All passengers affected by any schedule changes are being contacted and customers should always give up-to-date contact details, for both home and while away, when making a booking.