Solas Amita 3 Stainless Rear Right Propeller 13x21 for Volvo Penta DuoProp

The Solas Amita 3 13x21 is a stainless steel rear propeller that represents the “high gear” in Solas’ duoprop lineup for Volvo Penta. Paired with a 15x21 front prop (required for the C6 set), it enables high-performance boats to fully leverage their powerful engines, converting torque into maximum speed.

The 21″ pitch is significantly greater, meaning with each revolution the propeller moves farther through the water. This is advantageous if the engine has sufficient power to turn the props up to the optimal RPM. For boats that with 19P props easily hit or exceed their max RPM, switching to 21P can bring the revs down into the recommended range while simultaneously increasing speed.

Performance: You can expect a higher top-end speed under ideal conditions – for example, with a 21P duoprop set, a boat may gain a few knots versus a 19P set, provided the engine can produce the needed power. At cruising ranges, the RPM will be lower, contributing to a more relaxed ride. It should be noted that holeshot acceleration with 21P may be slightly more gradual than with 17P or 19P, since the higher pitch loads the engine more on takeoff. However, the presence of twin counter-rotating props in the system helps maintain good thrust even with the higher pitch.

When to choose 21P? If your boat is relatively light for the engine’s power (for example, a 20–23 ft sport boat with a high-output V8 or a diesel with strong torque) and currently the engine easily hits or exceeds WOT RPM with 19P props, then 21P is the logical next step. It will “tame” the RPM by putting the engine back into its optimal range, and likely increase your top speed. Important: If with 19P you are barely reaching WOT or not at all, a 21P will overburden the engine – in that case, stick with a lower pitch to protect your motor.

Installation: The Solas Amita 3 8531-130-21 installs just like the other rear props in the series – onto the 19-spline shaft, after the matching 15x21 front prop is in place. Ensure you have the proper front 21P prop; Solas offers a corresponding model for the C6 set. Follow the manufacturer’s torque specs and instructions during installation, and always secure the prop with the correct cone and locking mechanism.

Max Performance Tip: To get the most out of a 21P duo-prop setup, operate the boat in lighter load conditions and trim the drive appropriately to reduce drag. Keep your boat’s bottom clean, as any fouling can negate the speed gains of a higher-pitch prop. With the Solas 15x21 + 13x21 combination properly matched to a capable engine, you’ll experience exhilarating top speeds and efficient cruise performance, all while maintaining the superior handling characteristics of the Duoprop system.