Eugene Daley, from Athlone, Co Westmeath, was in third-class accommodation on his way to New York on the first voyage of the Titanic in April 1912.
He was below decks when the supposedly unsinkable ship, built in Belfast, hit an iceberg and began to go down with the loss of more than 1,500 lives.
But Daley survived and told his story to Dr Frank Blackmarr, a Chicago physician who treated passengers picked up from the freezing water. The doctor kept a scrapbook of the tragedy, which is being sold at Christie's East in New York on February 17th. Daley boarded the ship at Queenstown and his detailed three-page account "is the most moving description I have seen of all the survivors' stories because it shows the difference between the social classes on the Titanic", Ms Marie Kotsonis, a specialist at Christie's, said.
"It tells of being held below decks for what seemed a lifetime and a final rush of men up the stairways with weapons. He describes how two `dagos' were shot and others punished by the officers.
"Mr Daley finally got to the third-class promenade deck with a set of Irish bagpipes, saluted his homeland with a rendition of Erin's Lament, and then jumped over the side."
She said: "Daley describes his good fortune at climbing aboard a collapsible lifeboat, of people being sucked down the Titanic's funnels like flies, and having to keep people off the lifeboats in order to save themselves.
"He tells of one man who, when asked not to board, said simply, `God bless you, goodbye,' and just disappeared into the night. It is phenomenal stuff."
Blackmarr was a passenger on board the Carpathia, a liner which went to the aid of the Titanic. After being rescued, Daley was found collapsed outside the doctor's cabin and was treated.
His story then emerged, but he was too cold to write it down. The account was dictated and then signed by Daley afterwards on Blackmarr's stationery.
It is one of several graphic accounts by passengers, who describe jumping over the side to try to escape drowning. Water was up to the knees of those in Daley's lifeboat and two men died of exposure before the Carpathia arrived.
Blackmarr also took photographs at the time and kept them with the archive, which passed down in his family.
Ms Kotsonis said: "At one stage the scrapbook was almost thrown out with the trash, but the owner had second thoughts and took it to a local saleroom just outside Chicago.
"It was bought for very little there by the current owner, who brought it in here. We expect it to do very well."