The 64-year-old vessel was due to begin its summer season last Friday with a series of excursions on the Clyde but she instead spent what should have been a busy holiday period was at Garvel drydock in Greenock for repairs following "technical difficulties".
Operator Waverley Excursions said it was a serious setback to its campaign to raise £250,000 to ensure that this will not be the last year the elegant craft travels 'doon the watter' after rising fuel costs and a series of inclement summers have seen it struggle to survive.
Chairman of Waverley Excursions Graeme Hogg said the cancelled sailings had cost the group between £30,000 and £50,000 as berthing dues, crewing costs and advertising still had to be paid. All customers who had booked an excursion had been offered a refund or alternative sailing, he added.
"We needed to raise £350,000 to break even but we already have £100,000, which has given us a target of raising £250,000 this year.
"But this weekend's costs will hit us hard. We're looking at whether we can enlist more public sector support. We need something sooner rather than later," he said.
"We rely on good weather to boost our passenger numbers so if the sun shines from now to October people will come for a sail. But given the summers we have been having, there's obvious uncertainty."
The problems have been blamed on delays in repairs to the ship's steering mechanism, problems which were revealed during a routine five-year mechanical survey.
But as the company realised the ship would not be ready to sail only towards the end of last week, it had not been possible to tell everyone who booked tickets, resulting in some people having to be turned away from her Glasgow berth from where she was due to sail on Friday.
Further sailings on Saturday, Sunday and an excursion from Glasgow via Largs to Ireland yesterday also had to be cancelled, although the Waverley is scheduled to travel to the Bristol Channel for a series of excursions beginning on Saturday.
Kathleen O'Neill, general manager of the Waverley, said: "The poor weather over the weekend would have put some people off sailing but it still expected to have some busy sailings.
"The five-year survey for the steering mechanism was due this year.
"We took it out and sent it off to a machining shop in central Scotland but unfortunately it didn't come back in time."
"We found out between Wednesday and Thursday of last week that the stuff wasn't going to be put back into the boat in time.
"Obviously it's going to be a blow to us as we still have to pay all out costs."
It was reported last month that the Waverley needed £500,000 to see the season through and pay for repairs ahead of next year's sailings.
However, it is hoped half of that will be raised by fare revenue.
Waverley Excursions has struggled to raise enough to cover its fuel costs, which have risen to £400 an hour as global oil prices have risen, and the group has seen passenger numbers dwindle over the last three years as inclement weather has deterred passengers.
It receives £26,000 annual funding from Glasgow City Council but is trying to secure further public funding to ensure it stays in business.