Second officer Charles Lightoller's statement was taken in New York days after Titanic sank in the Atlantic waters in 1912.
According to his statement, he felt a "slight jar" when the luxury liner hit a "small and low-lying" iceberg.
The iceberg was actually up to 100ft high by 400ft wide, but the 46,000-tonne ship was speeding through an icefield at night and crew failed to spot it in time.
The statement is now set to fetch 12,000 pounds at auction in Devizes, Wilts, on April 26.
More From This Section
"The captain was on and off the bridge throughout the watch. A sharp lookout was kept from the crow's nest. The ship was on course South 86 degrees West true when the lookouts reported ice dead ahead," the statement reads.
"The first officer immediately starboarded the helm reversed the engines full speed and closed all watertight doors.
On April 10, 1912, Titanic set sail on its maiden voyage, travelling from Southampton, England to New York.
More than 1,500 of the ship's crew and passengers died when it hit an iceberg and sank, five days into its trip across the Atlantic.