 Fire control technology advanced quickly during the years immediately preceding World War I and the development of the Dreyer Fire Control Table was one such advance . It combined the functions of the Dumaresq and the range clock and a simplified version , the Mk I , was fitted to the Indefatigables during refits in 1915 – 16 . The more important development was the director firing system . This consisted of a fire @-@ control director mounted high in the ship which electrically transmitted training and elevation angles to the gun turrets via pointers , which the turret crewmen had only to follow . The director layer 's trigger fired the guns simultaneously which aided in spotting the shell splashes and minimized the effects of the roll on the dispersion of the shells . A gun within the ' Y ' turret was also equipped with transmitters so that , as a backup , it could function as a " directing gun " , but there was no provision for the gun battery to be split between the main director and this directing gun . The Indefatigables received their director equipment between mid @-@ 1915 and May 1916 . 
