Why Tribal-class destroyers suffered turbine blade rubbing

What caused turbine blade rubbing in Tribal-class destroyers?

The Tribals routinely operated much faster than their designed cruising profile, producing turbine vibration and blade rubbing across engines from different makers.

Royal Navy machinery was designed around ships spending much of their service at cruising speed, but the heavily demanded Tribals frequently dashed between tasks at much higher speeds. Their turbines began to wobble and suffer blade rubbing because the machinery was repeatedly used outside that expected operating pattern. Ships with different engine makers showed the same trouble, so investigators compared employment profiles and found that the class's average service speed was far above its nominal cruising speed. The approximate figures given are a 16-knot design cruising speed and 22 to 24 knots in average service, with a warning that the exact class-wide figure was not remembered. This experience influenced changes to the turbine installations of the later Battle and Daring classes.