Historical instances of plank walking
In 1769, mutineer George Wood confessed to his chaplain at Newgate Prison that he and his fellow mutineers had sent their officers to walk the plank.
In July 1822, William Smith, captain of the British sloop Blessing, was forced to walk the plank by the Spanish pirate crew of the schooner Emanuel in the West Indies.
The Times reported on February 14, 1829 that the packet Redpole (Bullock, master) was captured by the pirate schooner President and sunk. The commander was shot and the crew were made to walk the plank.
In 1829, pirates intercepted the Dutch brig Vhan Fredericka in the Leeward Passage between the Virgin Islands, and murdered most of the crew by making them walk the plank with cannonballs tied to their feet.
It was said that forcing loyal seamen to walk the plank was supposed, by the perpetrators, to "avoid the penalty for murder" (by not actually killing the victims), but this would hardly have worked. Not only would most legal authorities not have hesitated to prosecute any person who forced another to his death, but piracy and mutiny were also capital crimes. Given the occasions on which it was known to have been employed, it appears more likely to have been an elaborate and unusual form of sadistic entertainment rather than a regular method of murdering unwanted captives.
Although walking the plank plays a large role in contemporary pirate lore, in reality walking the plank was a very rare phenomenon, most pirates and mutineers having little reason to undertake elaborate psychological torture on their prisoners if they intended to kill them anyway.