=== Constant Velocity ===
In a constant-velocity (CV) anti-vibration system such as the AquaDrive®,<ref>AquaDrive, http://www.aquadriveusa.com/advantage/advantage.htm</ref> there is a propeller shaft and a separate drive shaft, coupled with a CV joint. The propeller shaft ends in a [[ThrustBearing|thrust bearing ]] mounted to the hull.
This bearing takes the end-thrust from the propeller and transmits it to the hull to move it through the water. The drive shaft has a CV joint at both ends, and is splined inside so that its length is adjustable. This allows the engine to be mounted on flexible rubber mounts.