CalMacs latest ferry Chieftain,seen here berthed at Gourock ferry terminal.
She serves the Gourock to Kicreggan route.
Belfast Coastguard Operations Centre sent Helensburgh Coastguard Rescue Team and Helensburgh's RNLI lifeboat, along with the Coastguard rescue helicopter based at Prestwick Airport. A police boat also attended as well as Scottish Ambulance Service crews.
Four people were recovered from the water by the lifeboat and the police boat, with three of the casualties taken to Gourock where they were met by Greenock Coastguard Rescue Team and assessed by paramedics before it was decided they did not require further treatment.
A fourth casualty was airlifted from the police boat and transferred to hospital by the Coastguard rescue helicopter.