While both gun turrets were rotated by steam power, the new forward guns were loaded by hydraulic power, unlike the original guns which were hand worked. "Thunderer" was the first ship to have hydraulic loading gear. From 1874, the forward turret alone was converted to hydraulic power operation for training (turret traverse), elevation and ramming. This allowed the turret crew to be reduced from 48 to 28; the aft turret remaining hand-worked as a comparison. Power operation was considered successful, although it was later implicated in the 1879 explosion.