The woman, who could not swim, held on to the stricken vessel in the water off Hervey Bay for at least two hours until a rescue boat arrived after the man raised the alarm upon reaching the mainland.

Volunteer Marine Rescue Hervey Bay vice-commodore Jill Barclay said police notified the rescue base about 2pm after the man swam for about 45 minutes back to shore.

He used a bystander's mobile phone to call triple zero and was worried because he could no longer see the overturned 14-foot vessel from the shore, which was being blown further out to sea.

Ms Barclay said rescuers found the woman still holding to the catamaran about 3.15pm. The rescue boat plucked her from the water and towed the vessel back to the mainland.

Ms Barclay said the couple in their 50s were locals, but had only gone out on their vessel a few times.

"The lady was quite distressed when we found her and we got the ambulance service to check her out," Ms Barclay said.

"The man was fine apart from being in a worried state because he couldn’t see the boat from shore after calling triple zero.

"These things [catamarans] go over really quickly. If a bit of wind hits them on the wrong side of the sail, they flip quite quickly.

"It was blowing quite hard yesterday, with 20-25 knot winds and rough seas."

Ms Barclay said Marine Rescue Hervey Bay responded to about half a dozen overturned vessels annually, mostly when kitesurfers or small vessels were not able to right themselves.

On Christmas Day, a 25-year-old man was winched from Gold Coast waters by the Westpac Lifesaver Rescue Helicopter after his jet ski broke down and capsized in the Gold Coast Seaway.

In November, a Hawaiian tourist spent the night sitting on his boat after it capsized off Mackay.

The 29-year-old man was winched from his overturned catamaran by the RACQ CQ Rescue helicopter and rescuers say the emergency beacon he activated could well have saved his life.