Islands Unlimited has now cancelled all inter-islands sailings until 10 September because of a mechanical problem.
The San Pawl broke down before the Bank Holiday weekend.
Passengers travelling to Jersey on Friday evening (28 August) had to be transferred to the Manches Iles Express.
The ferry company originally cancelled sailings to 6 September.
In an update yesterday, it said it has extended the suspension of services to 10 September.
"Every affected booking will receive a full refund, processed automatically back to the original payment method.
"Passengers do not need to take any action.
Islands Unlimited has apologised and says it will give an update on other future sailings before the end of this week.
"At that point, we will confirm whether those future sailings can operate or whether additional cancellations will be required.
"We sincerely apologise for the disruption and uncertainty this situation is causing. Our team is working continuously to resolve the issue and restore services safely and reliably.
"Thank you for your patience and understanding."
There was further disruption for ferry passengers over the long weekend, with DFDS and Brittany Ferries fast ferry sailings from the UK and France cancelled due to strong winds and high seas.
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