It is important to select the correct size pump as it directly influences the ability of the Autopilot to steer the vessel. An Autopilot Drive will need to give a nominal “Hard over time” of 10 to 12 seconds (Or as specified by the Autopilot manufacturer). The type of vessel to be steered must be considered. The “Hard over time” may be faster on lightweight Planing Craft/ Modern yachts and slower on displacement power boats/ long keel yachts. Note if the pump is too large, the vessel may over steer and will use more power; Too small and the Autopilot may struggle to maintain a course. “ Hard Over Time” Is the time that the pump takes to drive the rudder from port to starboard stops. “Dock side” (no flow over the rudder).