He grabbed the branch of a fig tree that grew above the whirlpool and hung there until Charybdis began to spew water. Together with water came the mast of the ship, clinging to which Odysseus managed to swim further.
Detailed answer:
In ancient Greek mythology, Charybdis is a sea monster. In Homer’s Odyssey, Charybdis was represented in the form of a terrible whirlpool. He absorbed and spewed water in a narrow strait three times a day.
For the first time, Odysseus meets Scylla and Charybdis on his way to his home island of Ithaca. When he and his companions passed the narrow strait between two rocks, Charybdis greedily consumed the water. Death from Charybdis threatens everyone, while Scylla could grab only six people with its paws. At the request of Eurylochus, one of Odysseus’s comrades, they landed on Trinakia, the sun god Helios’ island. The storms held them there for a month. Despite Odysseus’s warning, his men killed the god’s flocks while Odysseus slept. Zeus decided to punish them with a storm at sea, during which only Odysseus was saved.
Later, Odysseus meets with Scylla and Charybdis again. The wreckage of the ship was already on its way into the whirlpool. However, Odysseus grabbed the branches of a fig tree, descended to the water, and hung in this position until Charybdis threw back some logs. Riding them, he managed to get out of the whirlpool.