During the trials of H.M.S. Daring (length 185 feet, beam 19 feet; draught 7 feet) run over the Admiralty measured mile on the Maplin Sands H.M.S. Daring reached the unprecedented speed of 29.3 knots, and achieved an average speed of 28.6 knots during three runs over the measured mile. It was noted that there was a complete absence of engine vibration. This was attributed to the Thornycroft system of engine balancing in which the cylinders were arranged in pairs, and 180-degree cranks, so that the inertia stresses were balanced. Each engine had two such pairs, making a total of eight cylinders. H.M.S. Daring was the first of five torpedo boats built by Messrs. J.I. Thornycroft and Co. that formed part of the admiralty's new destroyer flotilla. They were armed with six quick-firing guns of different calibre, and provision was made for fitting them out as torpedo vessels if required.