When Volvo Penta introduced the DuoProp in 1982, a modern, superior boating experience was born. This innovative drive system, with twin propellers sharing the same drive shaft but rotating in opposite directions, has delivered families enjoyable experiences on the water for years to come.
Dual-prop technology first came to the attention of Volvo Penta engineers through an unlikely source, the Swedish navy, who used the design to enhance the stability of torpedoes. By bringing the concept to the recreational market, the company proved that boaters could also benefit from improved thrust, better tracking and faster acceleration, especially on larger and heavier models.
Let’s take a closer look at the revolutionary Volvo Penta DuoProp.
Innovative Design
Although often referred to as “counter-rotating,” Volvo Penta’s DuoProp actually features two contra-rotating propellers, meaning the props are mounted to the same singular driveshaft. The design offers boaters many of the same advantages of twin engines with counter-rotating props, but in a single, more compact drive unit. The result is significantly less cost up front for one engine instead of two, lower fuel bills over the course of a boating season, and reduced maintenance concerns long term.
More Blade Surface
One obvious advantage of dual props is the significant increase in blade surface they offer, accompanied by a reduction in prop slippage. Practical benefits include more lift at the stern resulting in quicker planing times, lower planing speeds, less bow rise while running at speed, even up to 30 percent faster acceleration and 10-to-12 percent lower fuel consumption. Top speeds can also increase as much as 5 percent. These advantages over a single prop are even more obvious when a boat is heavily loaded with passengers and gear. And all without the increased drag that would come with running a comparable larger diameter, single prop.
Superior Maneuverability
DuoProp is also renowned for its positive impact on both straight-line tracking and maneuverability. Twin, contra-rotating props effectively offer a better “bite” on the water, providing enhanced traction and allowing a DuoProp-equipped boat to respond quicker to input at the wheel. This increased maneuverability is even more pronounced at low speeds when maneuvering a tight dock, marina or launch area. A captain will find they are able to better compensate for current and wind and the boat’s turning radius will be tighter.
Improved Reverse
DuoProp also offers superior maneuverability in reverse. Propellers naturally lose bite due to exhaust gases passing over the blades and causing slippage. Single-prop boats also effectively steer away from the natural bite of the propeller’s one-directional blades, often causing a boat to pull in one direction or the other. Contra-rotating props counteract this steering torque and give boaters complete confidence to handle even the tightest — or trickiest — confines.
Enhanced Ride Experience
Rounding out the advantages, precise balancing minimizes vibration, preserves drivetrain life and results in a quieter, virtually cavitation-free ride. DuoProp is also poised to play a critical role in new technologies including hybrid-electric, pure electric and other alternative power solutions.
