Legal framework and relation to piracy
The letter of marque of a privateer would typically limit activity to one particular ship, and specified officers. Typically, the owners or captain would be required to post a performance bond. In the United Kingdom, letters of marque were revoked for various offences.
Boarding of the Triton
(a British East Indiaman) by the French corsair Hasard
Some crews were treated as harshly as naval crews of the time, while others followed the comparatively relaxed rules of merchant ships. Some crews were made up of professional merchant seamen, others of pirates, debtors, and convicts. Some privateers ended up becoming pirates, not just in the eyes of their enemies but also of their own nations. William Kidd, for instance, began as a legitimate British privateer but was later hanged for piracy.
While privateers such as Kidd were commissioned to hunt pirates, privateering itself was often blamed for piracy. Privateering commissions were easy to obtain during wartime but when the war ended and privateers were recalled, many refused to give up the lucrative business and turned to piracy. Colonial officials exacerbated the problem by issuing commissions to known pirates, giving them legitimacy in exchange for a share of the profits or even open bribes. The French Governor of Petit-Goave gave buccaneer Francois Grogniet blank privateering commissions, which Grogniet traded to Edward Davis for a spare ship so the two could continue raiding Spanish cities under a guise of legitimacy. New York Governors Jacob Leisler and Benjamin Fletcher were removed from office in part for their dealings with pirates such as Thomas Tew, to whom Fletcher had granted commissions to sail against the French, but who ignored his commission to raid Mughal shipping in the Red Sea instead. Kidd himself committed piracy during his privateering voyage (though he maintained his innocence and blamed his unruly crew) and was tried and executed upon his return. Boston minister Cotton Mather lamented after the execution of pirate John Quelch: "Yea, Since the Privateering Stroke, so easily degenerates into the Piratical; and the Privateering Trade, is usually carried on with so Unchristian a Temper, and proves an inlet unto so much Debauchery, and Iniquity, and Confusion, I believe, I shall have Good men Concur with me, in wishing, That Privateering may no more be practised, except there may appear more hopeful Circumstances to Encourage it."