Denying he abandoned his post when the ship struck the island of Giglio in the Tyrrhenian Sea off the coast of Tuscany, he said the proposed book would "recount a completely different story and will show I am not Captain Coward."
"I will no longer accept being massacred with slanderous lies. I'm writing a book and I will reveal what people don't want to come to light," he said in an interview with the Italian newspaper Il Giornale.
Schettino said after reaching land in a lifeboat, he attempted to return to the ship in a dinghy to help with the chaotic night evacuation, but turned back when the dinghy took on water.
His account diverges from those of survivors and crew, who said he made no attempt to return to the ship after he reached the shore of Giglio, the British newspaper The Daily Telegraph reported Friday.
The shipwreck is still under investigation in Grosseto, Italy, and a decision to try Schettino on charges of abandoning ship, causing a maritime disaster and multiple counts of manslaughter has yet to be made, The Daily Telegraph said.