The MV Loch Riddon had just left the port for the 10-minute trip to Cumbrae when a problem was detected with the hydraulic ramp.
It was decided to return to the port in an attempt to repair the problem.
A CalMac spokesman said 57 people and six cars were on board the 11.45am sailing.
He added: "The vessel had only just left Largs when the crew noticed a problem with the hydraulic ramp."
The Loch Riddon tied up at the port but it was decided passengers could not disembark safely so they were kept on board and were given hot drinks and water.
A temporary fix was carried out and all the passengers and cars were eventually allowed off the vessel at 1.30pm.
One woman who was on board said: "We were right next to the land but nobody could get off because the on-off ramp got stuck mid way.
"They disrupted passengers' holidays.
"Staff handed out water and cups of tea but there were restless children and angry passengers."
The CalMac spokesman said: "A temporary fix was done which got them off at 1.30pm and the boat went back into service at 4pm.
"Passengers were given drinks while they were waiting so we looked after them."
The company also operates the MV Loch Shira, which also sails between Largs and Cumbrae.
In summer, vessels sail between the two ports every 15 minutes for most of the day.
Cumbrae is one of the smallest islands on the Firth of Clyde and is popular with cyclists.