Monty Phillips had planned to take the last ferry to travel home to Dunoon from Paisley after visiting an ill friend in hospital.
But the 49-year-old found the passage had been cancelled due to bad weather after arriving at the Gourock ferry terminal to catch the 10:40pm journey on 11 April.
The ferry service is run by Argyll Ferries.
The final bus service had left from the location an hour earlier.
Mrs Phillips claimed a member of staff at the ferry terminal refused to unlock the waiting room for her to stay in.
With no money for a hotel or taxi, she decided to take shelter in a nearby grit bin full of rock salt where she slept for the night.
Mrs Phillips cares for her 89-year-old mother and said she had arrived in plenty of time for the final ferry service on the night.
“When I got to the ferry terminal I was met with a sign saying the final replacement bus had been at 9:45pm and nothing was in place for the last sailing,” she told The Sunday Post.
“The waiting room was locked and in darkness and the staff member said he couldn’t unlock it as it was alarmed.
“When he realised I was there for the evening after he locked up he said he could phone me a taxi, but if I could have paid for a taxi I wouldn’t have been sitting outside.
“And I didn’t have the money to put myself up anywhere for the night. He asked me ‘is there nowhere local you can go?’ But there wasn’t.
“When he offered me a jacket, I just gave him a look of incredulity. I couldn’t believe that was the extent of the help being offered.”
Mrs Phillips chose not to call her 23-year-old daughter, whose had been experiencing problems with her car, for help.
She said she didn’t want her daughter attempting the four-hour round trip by road from Dunoon to Gourock.
“I was starting to get really cold,” she said.
“There was nowhere I could sit that was keeping the wind off me. It was a case of finding somewhere to rest, out of the wind.”
Mrs Phillips added: “It was a long and uncomfortable night until 6am the next morning. I didn’t get any sleep at all. I was too scared and too cold to sleep.”
Argyll Ferries said customers had been told through their website and text message service that sailings would be cancelled due to adverse weather conditions.
A statement issued by the ferry service said: “A replacement bus service was offered up to the last possible Western Ferries return sailing.
“Staff tried to assist the customer concerned as much as they could, offering to call a taxi and even to drive her somewhere local if that would help.
“All offers of assistance were refused. We are sorry for any inconvenience the passenger experienced, but in the circumstances there was nothing else we could do to help.”