MV lord of the Isles, which provides the lifeline service to Barra and South Uist, has been taken out of service for essential hull repairs.
Investigations into the cause of the hull damage are underway.
The MV Isle of Mull did a late service to Lochboisdale last night to pick up her traffic and is now back on the Oban Craignure service.
MV Hebridean Isles will pick up MV Lord of the Isles services from this afternoon until she returns to service which CalMac hope will be over the weekend.
MV Clansman is unaffected.
A CalMac Spokesman apologised for any inconvenience caused.