The Royal Hellenic Navy, led by Rear Admiral Pavlos Kountouriotis on board the flagship Averof, defeated the Ottoman Navy, just outside the entrance to the Dardanelles (Hellespont). During the battle, Kountouriotis, frustrated by the slow speed of the three older Greek battleships Hydra, Spetsai and Psara, hoisted the Flag Signal for the letter Z which stood for "Independent Action", and sailed forward alone at a speed of 20 knots, against the Ottoman fleet. Taking full advantage in her superior speed, guns and armour, Averof succeeded in crossing the Ottoman fleet's "T" and concentrated her fire against the Ottoman flagship Barbaros Hayreddin, thus forcing the Ottoman fleet to retreat in disorder. The Greek fleet, including the destroyers Aetos, Ierax and Panthir continued to pursue the Ottoman fleet off-and-on between the dates of December 13 and December 26, 1912.
The Ottomans suffered 7 killed and 14 wounded on the Barbaros Hayreddin, 8 killed and 20 wounded on the Turgut Reis, and 3 dead and 7 wounded on the Mesudiye.
This victory was quite significant in that the Ottoman navy retreated within the Straits and left the Aegean Sea to the Greeks who were now free to occupy the islands of Lesbos, Chios, Lemnos and Samos. It also prevented any transfer of Ottoman troop reinforcements by sea and effectively secured Ottoman defeat on land.