On March 18, 1915, the Allies fleet consisting of 18 battleships and cruisers and numerous destroyers tried to force through the narrowest passage of the Dardanelles which was only 1500 meters wide.
Despite the threat of cannons, Ottoman minesweepers were ordered to participate in the assault. At 14 pm, a report of the Ottoman headquarters reported that “all the phone lines were cut off all communications with strong are broken, some guns were affected … therefore the artillery defences have was severely reduced”. Allied reconnaissance did not, however, identified all minefields setup by the Ottoman and the French battleship Bouvet sank in two minutes with over 600 sailors after hitting a sea mine.
The HMS Irresistible and HMS Inflexible also struck sea mines while the HMS Ocean, sent to rescue the first experienced the same fate and the two ships both sank. The French battleships Suffren and Gaulois were also damaged trying to cross through a line of sea mines which was planted discreetly ten days earlier by the Ottoman minelayer ship Nusret.
These heavy losses forced Admiral John de Robeck to order a retreat to save what was left of the fleet. Some officers like Commodore Roger Keyes of HMS Queen Elizabeth felt that victory was at hand because the Ottoman batteries had almost no ammunition but Robeck, John Fisher and other commanders thought that naval attempts to take control of the straits would require unacceptable losses. The Allied withdrawal strengthened the morale of the Ottomans and today March 18 is celebrated in Turkey as a great victory.