Actual casing from sea mine used by Ottoman Navy. Mines were laid perpendicular to the current, in the narrower parts of the Dardanelles (about 1 km at the narrowest). The Allied (British and French) ships started shelling the forts and the shore batteries protecting the mine fields in February, 1915 Sometime in early March, Ottoman officers noted that the Allied battleships turned in a particular wide spot of the strait after taking their turns shelling the Ottoman shore batteries...