Warship Speeds - back in the very late 1930s the RN found a need for some fast minelayers - these ships were called the Abdiel Class, and six were built, coming into commission beginning in 1941.
Basically, they were oversized destroyer-sized hulls fitted up with cruiser propulsion systems of around 72,000 hp.
The specs were for a maximum speed of 40 knots, but the engineers could 'Pull the Foot' on the steam plants and increase the output to the point where both Apollo and Manxman were reputed to have exceeded 43 knots! Pretty good for a 400 ft, 3,400 ton displacement warship!
These ships were used for all sorts of high-speed tasks (eg - keeping Malta supplied at the height of the blitz, sneaking into Axis Mediterranean ports at night and placing mines in the shipping channels, then being hundreds of miles away by breakfast time). Three were sunk by enemy action during the war, but I think it was Manxman that remained in service until 1972.
Numerous stories involving her speed, racing other ships, etc, can be found on-line.