Enhanced performance parallel loop blade propellers may include a propeller hub having a fore hub end and an aft hub end. A plurality of looped blade pairs may extend from the propeller hub in spaced-apart relationship to each other. Each of the looped blade pairs may include a fore blade which extends from the propeller hub proximate the fore hub end. An aft blade may extend from the propeller hub proximate the aft hub end. The aft blade may be disposed generally within a common blade pitch plane as the fore blade in an adjacent one of the looped blade pairs. Accordingly, the fore blade and the aft blade of each corresponding looped blade pair may be disposed in generally parallel relationship to each other. A blade bridge may extend from the fore blade to the aft blade in each looped blade pair.

A marine controllable-pitch propeller is mounted on a drive shaft. The marine controllable-pitch propeller has a propeller blade comprising an offset pitch interface, a pitch adjusting member that is adapted to be linearly movably mounted on the drive shaft and connected to the offset pitch interface, such that a linear motion of the pitch adjusting member along the drive shaft results in a pitch adjustment of the propeller blade, a rotary actuator, a linear actuator operationally arranged between the rotary actuator and the pitch adjusting member, and translation means for translating a rotary motion of the rotary actuator about the drive shaft into a linear motion of the linear actuator along the drive shaft. The pitch adjusting member is rotationally fixed to the propeller blade.