This paper argues that two successful corsair admirals, Hayreddin d. 1546 and Mezemorta d. 1701, endeavored to establish a naval vision in the Ottoman Empire by reorganizing the Ottoman navy in two challenging periods of naval defeat. Hayreddin Pasha, Ottoman grand admiral 1534-46, originally from Lesbos, engaged in naval activities with his brother, Uruc. After backing the wrong Ottoman prince, they transferred their activities to the vicinity of Algiers where Hayreddin carved out a state. Due to unrest, he submitted to Selim I, and Algiers became an Ottoman province. When serious naval defeats awakened Süleyman to the necessity of employing an experienced naval commander as the admiral, Hayreddin returned to the Ottoman heartlands with experienced corsair captains and proceeded to transform the Ottoman navy into an effect naval power. He defeated the combined Venetian and Habsburg fleets at the battle of Preveza in 1538. Under Hayreddin’s leadership the Ottoman fleet was a powerful tool of diplomacy and force in advancing Ottoman interests in the Mediterranean. After his death in 1546 when his clients guided the navy, it remained effective, but political appointees periodically led the navy to disaster. At the end of the 17th century, the Ottoman Empire faced serious defeats because of their weak navy which had led to the loss of the Morea (Peloponnesus) to Venice. Once again, the sultan and his advisers turned to a corsair naval professional from Algiers, although Mezemorta may have originally been from Majorca, not Ottoman territory. Mezemorta had also spent many years as a successful governor and naval leader in Algiers before he was promoted to admiral in 1695 with the task of winning naval battles and reforming the Ottoman fleet. While serving as admiral he issued a new set of naval regulations. This paper analyzes the Gazavat-i Hayreddin Pasha and Ottoman historians Katib Çelebi, Raşid and Silahdar in addition to Muhimme orders. These sources reveal how Hayreddin and Mezemorta transformed weak Ottoman naval forces into an effective fighting force through their thorough understanding of naval warfare gained by experience in North Africa. Although separated by 150 years the reforming activities of admirals with naval vision revitalized the Ottoman fleet by providing personnel and training to provide qualified seafarers to lead the navy.