Why are the Pequod's planks dented?

Pequod's planks are deformed because of Captain Ahab's constant pacing with his peg-legged on Pequod's deck. Captain Ahab was out for revenge after the big white whale had bitten his leg. After his leg had been bitten off, it was replaced with a peg that is made from whale bone.

This is question was drawn from the whale, a novel by American writer, Herman Melville. It is the story of Ahab, the captain of the ship called 'Whaler, who want to take revenge on a whale who bit off his leg. The planks are dented because, Ahab, the captain of the ship has an amputated leg, and the dents represent the frequency of his walking up and down the deck with his peg leg.