The introduction of centralized fire control for warships gave a significant improvement to the accuracy of gunnery. The increasing range of naval guns led by several years the necessary advances to control their fire. Over a ten-year period techniques such as centralised spotting of fall of shot, mechanical computation of rate of change of range (rate), mechanical clocks to calculate range over time for any given "rate" and long baselength optical rangefinders were introduced. In order to make sense of such data, manual plotting of rangefinder ranges, from single or multiple rangefinders as well as other data began to find favour. The Royal Navy sponsored research into these techniques, and two groups emerged, a commercial group led by Arthur Pollen, and a Naval group led by Dreyer. Both camps aimed to produce a combined mechanical computer and automatic plot of ranges and rates for use in centralised fire control. Both systems were ordered for new and existing ships of the Royal Navy, although the Dreyer Table, as the Dreyer system was called eventually found most favour with the Navy in its definitive Mark IV* form.