According to BAE HMS Queen Elizabeth has a maximum speed of 25 knots but typically in projects like this, the maximums are understated.
The 70,600 tonne vessel reached speeds of 27.1 and also 29 knots on separate occasions, according to AIS.
The automatic identification system (AIS) is a tracking system used for collision avoidance on ships and by vessel traffic services. Information provided by AIS equipment, such as unique identification, position, course, and speed, can be displayed on a screen or in a simpler format on many websites.
Each ship features two power MT30 Gas turbines, that according to Rolls Royce are part of their efforts pioneering the use of aero-derivative gas turbines:
“Rolls-Royce pioneered the use of aero-derivative gas turbines in marine propulsion, primarily for naval vessels. The MT30 Gas turbines that power the Queen Elizabeth class aircraft carriers are the most powerful in-service gas turbines in the world.
Designed for the 21st century navies, the MT30 integrates the very latest in gas turbine technology to give efficiency and reliability with a market leading power to weight ratio. It has been designed to minimise maintenance costs and first entered service in 2008 powering the US Navy’s first littoral combat ship – USS Freedom.
Produced in Bristol, the MT30 Gas turbine and alternator sets are each located under one of the ships islands.”
Navies rarely give accurate estimations of speed, preferring to keep potential opponents guessing, but HMS Queen Elizabeth has comfortably exceeded her original maximum and it’s estimated by some that the design is capable of 32 knots however that can not be publicly verified.