"Walking the Plank" is a largely Hollywood invention, as a matter of fact. There is only one mention of the practice from the period, and that is in Francis Grose's Dictionary of the Vulgar Tongue, which itself was not published until 1785, long after the Golden Age of Piracy.

More common was keelhauling. Originally devised by Dutch sailors, the offender was tied with a weighted line to the ship while it was in motion, and then tossed under the hull where they would be dragged across the keel of the ship, which was covered in sharp barnacles. This could result in serious injuries, including losing limbs and decapitation.

Invented as a literary device by Robert Lewis Stevenson, long after the golden age of Caribbean piracy. The standard death penalty for pirates, per the articles (ship constitutions) that we have copies of, was marooning: the convicted was put ashore on a tiny piece of land in the middle of the ocean with one skin of fresh water, a pistol, and a couple of rounds of ammunition so that he could end his own suffering short of dying of dehydration if he so chose.

For lesser offenses, fines were usually levied against their eventual share of the loot. If it was just a question of not getting along, they could be put ashore at the next pirate haven or pirate-friendly town to catch a different ship.

Some ships' articles allowed the crew to vote for lesser punishments than marooning, such as whipping, but not very many ships: too many pirate sailors associated the lash with the kinds of cruel captains they signed the articles to escape.

tl;dr: The plank, never. Actual punishments ranged from fines, to (in some rare cases) beatings, to being "fired" and made to find another ship to work on, to a sentence of death by the convicted's choice of suicide or dehydration.

Selected sources: Karraker, Piracy Was a Business; Burgess, The Pirates' Pact, Cordingly, Under the Black Flag