Emergency services were called to the scene at Brodick Pier at around 5.28pm on Thursday.
It is believed that 213 passengers and 26 crew were on board at the time of the collision.
A total of 17 people have reported injuries, and a number have been taken to hospital.
The Marine Accident Investigation Branch (MAIB) has been informed.
Eyewitnesses described ‘lots of injuries’ after the ship struck the pier.
Onlooker Gavin Saxby took to Twitter with a photo showing the vessel’s bow badly damaged.
He wrote: "Just on PS Waverley as they crashed it into the pier at Brodick, what a mess on board, lots of injuries, hope everyone recovers."
Mr Saxby told the Ardrossan and Saltcoats Herald: “I was up on deck, we were approaching the jetty and didn't seem to be slowing down and all of a sudden most people on the deck were knocked off their feet and there was a bang.
"The crew were on the ball, dealing with the first aid, keeping everything in order and once the ambulance crew had arrived and presumably all triage work done the uninjured passengers were allowed off."
A search and rescue helicopter rescue, based at Prestwick Airport, was tasked to attend the incident.
It is understood the force of the crash pushed passengers forward.
Eyewitness Dea Summer told the Largs and Millport News how she was due to board the ferry to travel back home to Largs when the boat struck the pier.
She said: “It was very windy and the boat was too fast, it was a very loud crash, it just sailed straight into the pier.”
Nobody from the ship's Glasgow-based operators, Waverley Excursions Ltd, was available for comment when contacted by The Scotsman.
The incident comes less than a month after the boat returned to service plying the Clyde following recent repairs.
The steamer has been recently undergoing a refit on her main boilers and had not been in service for two seasons.
Today's £37 excursion was scheduled to leave the Broomielaw in Greenock at 11:15am cruising down the Clyde viewing the islands of Bute and Cumbrae before crossing to Arran.
The boat had been expected to return at 8pm.
Karen Mulligan, 34, was on a birthday cruise with her husband and was on the top deck of the vessel when it struck the pier.
She said: "At first i didn't quite realise what was going on but the jolt made me slip down a few steps and so did my husband behind me and people in front of me fell off their feet and off their seats.
"I don't want to say there was bodies everywhere but there kind of was, to be honest. Everyone who wasn't hurt was checking everybody else and helping out. There was one guy with a broken arm and a doctor who was on board got him in a sling, and there was another guy who could not be moved because he had a slipped disc or something."
She said passengers were kept on the ship for about 30 minutes as paramedics arrived.
The Waverley, built in 1946, did not operate last year as it needed to raise money for urgent repairs.
Money was raised by more than 8,000 members of the public and £1 million was given to help the 70-year-old ship and its crew by the Scottish Government.
The Waverley, named after the debut novel of Sir Walter Scott, embarked on her first trip in June 1947, when she went from Loch Long to Arrochar, Argyll.
Before the pandemic, the vessel operated between May and October each year and carried around 130,000 passengers.
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