This is from the current Route Status Page for the route- https://www.calmac.co.uk/service-status?route=11
(This notice seems to have been posted at 1006 this morning, as I don't believe it was there yesterday, but the South Uist service service page says that the same thing happened last Wednesday- yet the South Uist timetable page has no service at all shown before 12 May. The fact that this happened last Wednesday was why I would have hoped that CalMac would have notified you by e-mail).
Furthermore the app should have notified you.
This is all to provide a once a week service to Lochboisdale, SouthUist, when it should be daily, and relieve pressure on the via Castlebay/Eriskay and the Lochmaddy routes. At the moment the whole situation with the big ships seems to be chaotic due to winter dry dock over-runs and the delayed entry into service of the MV Alfred as relief vessel. The Alfred now herself seems to have an unspecified technical issue and has now been found not to fit at least one link span on the first route she was meant to serve (Islay).
So timetables are being constantly rewritten and the reservation system constantly tweaked. The system is simply failing to keep pace with events.
Until they can get all the big ships all back into service, plus the MV Alfred, in early June (everyone hopes) the situation across the fleet will not ease. It could get worse next January when the MV Alfred goes off charter, if the new Glen Sannox is not yet in service.
I have never seen things so bad.
What on earth happens now if a big ship goes technical in the next 3 weeks is anyone's guess.
On the Highland Council Corran narrows service the army were asked to step in to resolve that situation, but they can't spirit a vehicle ferry from out of thin air, so two emergency passenger services, and an emergency bus service are substituting.
Wednesday 10 May- In order to provide a service to South Uist during the period of cancellations the following sailings will be cancelled: Depart Oban – 07:25, 09:55, 12:15, 15:55, 18:15. Depart Craignure – 08:45, 11:05, 13:55, 17:05, 19:25. Please be advised that due to these cancellations, some connections with other transport operators will not be met. Please note that all booking affected will be contacted in due course.
Anyway whatever the situation and narrative all that matters now is that you have secured passage for Wednesday, and that there are no weather or technical issues affecting your onward passage to Skye next weekend.