How does Odysseus survive Charybdis a second time?
Referring to the Scylla and Charydis section
In the twelfth book of Homer's Odyssey, the title character actually encounters Scylla twice. The first is when he sails past the monster in his only remaining ship. In that situation, he loses six of his crew.
The second occurs near the end of Book 12. After Odysseus and his crew leave the island of Thrinacia, Zeus strikes their ship with a terrible storm. The ship is smashed to pieces, Odysseus' men are drowned, and Odysseus manages to survive by hanging on to a piece of the ship.
Unfortunately, Odysseus drifts back toward the Scylla and Charybdis. The whirlpool sucks down the parts of the ship to which Odysseus was clinging. Odysseus himself manages to leap up and grab on to a branch that was hanging over the water. After hanging there for some time, Charybdis spits back up the pieces of his ship. Odysseus drops back down into the water, climbs on to the wreckage, and then paddles away. Thanks to Zeus, Scylla did not see Odysseus:
The Father of men and gods prevented Scylla noticing me, or I would never have escaped utter disaster. (A.S. Kline translation)
Charybdis was portrayed as a whirlpool that took water down the depths three times a day and brought it back up the same number of times. As seen when Odysseus was being advised on how to survive the two sea monsters Scylla and Charybdis. He was advised that it was best to avoid Charybdis at all costs since it meant complete wreckage of their ship. However on surviving the first time his crew arrived at an island (Thrinacia) where they fed on cattle belonging to Helios the sun god. While trying to escape they were pushed back to Scylla and Charybdis by Zeus avenging their misdemeanor on behalf of Helios. Their ship was wrecked by Charybdis and all but Odysseus survived by hanging on to a fig tree along Scylla as he waited for pieces of the wreckage to be brought back up again from the depths of Charybdis. When the pieces of wreckage were brought back up he released the fig tree and landed in the water then got on to one of the pieces and rowed using his hands through the strait and to safety.