How does duo prop work

Optimized torque distribution between front and rear propellers ensures that the drive works with the load it is designed for — essential in preserving the life of the drivetrain. Precise balancing of each propeller gives minimal vibrations, quiet and smooth operation.

It is also essential for efficiency and minimizes wear on the drivetrain. Shock-absorbing rubber bushings in the hub reduce vibration, turning and pulling forces and minimize stress on the drivetrain caused by gear-changes and propeller impact.

Galvanic isolation - the propeller bushing is designed to galvanically isolate the propeller from the drive. It will greatly reduce anode consumption and prevent galvanic corrosion that could be caused by the propeller. More information on propellers, including part numbers and propeller installation hardware can be found in the Volvo Penta Propeller Guide, see below. Designed to capture the tremendous torque from the latest generation D4 and D6 engines.

The patented blade geometry of the Type H propellers provides optimal interaction between front and rear propellers, for outstanding efficiency and smooth and comfortable operation. The large blade area provides maximum grip and maneuverability. Made of high-strength stainless steel alloy for excellent strength and durability. Complete with shock absorbing rubber bushing and galvanic isolation makes it perfectly matched for the DPI drive. The line cutter is included as standard. The patented blade geometry and large Active propeller diameter provide optimal performance and fuel efficiency over the entire speed range as well as smooth running, excellent grip and maneuverability.

Squeeze casting and special high-strength aluminium alloy render them stronger and more durable than traditional die-cast propellers. Four layers of paint ensure excellent anti-corrosion performance. Always use type F or FH stainless steel propellers in engines exceeding hp or capable of speeds above 38 knots 45 mph.

Previous type D propellers. Type I propeller sets replace previous type D propeller sets. However, type D propellers front and rear are sold individually as spare parts. This is the perfect upgrade for enhanced performance, strength and durability.

It provides better acceleration and higher top speed due to greater strength and thinner blades - versus a comparable aluminum propeller. The high-strength stainless steel adds excellent durability and corrosion resistance. Complete with a shock-absorbing rubber bushing and galvanic isolation, it is perfectly matched for the DPS-drive and the ultimate choice for demanding boaters. The patented blade geometry provides optimal interaction between front and rear propellers for outstanding efficiency and smooth and comfortable operation.

Complete with shock-absorbing rubber bushing and galvanic isolation makes it perfectly matched for the DPH-drive. With a total of six blades three blades on each prop the Dual Prop System provides more grip and propulsion to evenly distribute torque between each prop.

Coupled with the hydrodynamic gear case, the result is greater outboard efficiency and performance. This is achieved because the gear diameter can be reduced since the counter rotation propellers can disperse torque. It cuts down water resistance and increases speed. I think I can live with that and doesn't sound worth fretting about too much for the light use we are planning.

I get the point on two props - both would need to be maintained and potentially replaced Joined 25 Nov Messages 2, Location fareham hampshire. Joined 11 Jun Messages 1, If your drive destroys itself a duoprop will be more expensive to repair than a single prop, plus there are more seals with the potential to fail and let in water in a duoprop.

The positives to a duoprop are as per the posts above. Joined 16 Mar Messages 8, Location boat conwy. Have you thought how much maintenance budget will be with stern drives. Greg2 Well-known member. Joined 24 Jun Messages 3, Far more helpful than prop-walk on a single engine. I just didn't have any personal experience with them. I did, however, think "that's a great idea" when they first put it on the market. Methinks I made an error in my earlier message re the direction of prop walk; I've corrected it.

More on prop walk. All this is very scientific and it all make sense. All I know is that I ran a 35' trawler for several years with a single screw. All I had to learn was how to react to stern movement going forward or in reverse, especially when docking. I had it figured out to a science Without boat speed the rudder is useless.

It is one of the things that "true Sailors" have to learn. Never had an incident in "not" hitting the dock at the right place. Bow thrusters, twin screws were out of my vocabulary at the time. I was proud of every successful docking. Sometimes the human brain has an advantage..

Chien Hwa. Tom, your attention to detail and accuracy constantly amazes and delights me. I didn't catch your original reference to port thrust of the stern for the normal clockwise turning prop. I only remembered what my boat did. Stern to the right, bow to the left port , was what always happened to me.

Actually the condition was somewhat mitigated by the fact that the steering on my boats was done by the position of the outdrive rather than with a fixed prop and rudder steering.

Still, someone had to hold the wheel to prevent the tendency. I miss those days Like I always say, getting old was fun, being old sucks Carson, I've watched you "old salts" maneuver those big boats in tight places many times and marveled at your abilities. It's fun to watch the 50'ers, with dual engines, back down into their berths using nothing but the engines for steering.

The Captain will stand with his back to the console facing aft and play those throttles, behind his back, like a fine musical instrument. That boat settles in without a bump or a rub. It's the little things that make a lifetime of memories PancakeBill Well-known member.

West Yellowstone,MT. Yeah, but try it with just sails. Been there, done that.