Firing trials against in 1907 revealed this system's vulnerability to gunfire, as its spotting top was hit twice and a large splinter severed the voice pipe and all wiring running along the mast. To guard against this possibility, "Dreadnought"s fire-control system was comprehensively upgraded during her refits in 1912–13. The rangefinder in the foretop was given a gyro-stabilized Argo mount and 'A' and 'Y' turrets were upgraded to serve as secondary control positions for any portion or all of the main armament. An additional 9-foot rangefinder was installed on the compass platform. In addition, 'A' turret was fitted with another 9-foot rangefinder at the rear of the turret roof and a Mark I Dreyer Fire Control Table was installed in the main Transmitting Station. It combined the functions of the Dumaresq and the range clock.