It’s safe to say that the seven main advantages of having a dual prop drive on a boat are as follows:
- Increased blade area
- Reduced steering torque
- More precise maneuverability
- No “prop walk”
- Less cavitation
- Faster acceleration
- Better fuel efficiency
In return, the disadvantages of a dual prop drive system are as follows:
- Higher initial costs
- Fewer aftermarket props and parts
- Complexity
- Corrosion
- Faster idle speed
- Slower top speed
- Heavier weight
If you want to find out more about the pros and cons of a dual prop system, you’ve come to the right place.
We at PowerSportsGuide have compiled them all under one roof!
What Does a Dual Prop Drive Mean on a Boat?
As the name suggests, a dual prop drive features two propellers mounted directly behind each other. The rear prop has a smaller diameter and rotates in the opposite direction as the larger front prop.
This setup is often referred to as a twin prop, or duo prop drive as well.
Standard dual prop drives feature two 3-blade props, but some special models have four blades on the front prop and three blades on the rear.
Dual prop systems are typically available on larger boats with inboard engines and on outboards from 300 HP and up. (However, Yamaha manufactured some 2-stroke dual prop outboards with 150-200 HP engines.)
Let’s get down to the nitty-gritty and talk about the pros and cons of this system in detail!
7 Main Advantages of a Dual Prop Boat
1. Increased Blade Area
One of the key advantages of a dual prop drive is the increased blade area, which has many advantages, including:
- Less drag (compared to a larger diameter single prop)
- Better initial bite
- Increased stern lift
- Can handle the high torque of big-block engines
2. Reduced Steering Torque
Boaters agree that the other main advantage of dual props is their reduced steering torque.
This setup offers smoother and easier steering, which is a game-changer especially if the boat features a larger, 300-600 HP outboard.
3. Better Maneuverability
A dual prop drive system ensures much better maneuverability as well.
The props hard bite in the water translates to more responsive handling.
When it comes to slow-speed maneuvering, this system offers more precise speed control and steering, especially in reverse.
At higher speeds, the dual props ensure straighter tracking and tighter turns, along with fewer prop blowouts.
On top of that, they also help the boat stop faster, making your boat safer.
4. No Prop Walk
Prop walk is a common issue on boats powered by stern drives and outboard motors.
Since the two propellers are rotating in the opposite direction, it helps to significantly reduce or even eliminate prop walk.
5. Less Cavitation
Unlike their single-prop counterparts, dual prop drives are less prone to cavitating.
This is a key advantage since cavitation can have many negative effects on a boat.
But contrary to popular belief, dual prop dive systems can’t totally eliminate these issues.
Irresponsible handling or a prop misalignment can still cause cavitation on a dual prop boat.
6. Faster Acceleration
The two propellers can eliminate the lateral forces existing in standard single-prop drives.
This concentrated power means a harder initial bite and a lack of cavitation, which translates to greater thrust and a better hole shot.
This means the boat accelerates faster and needs less time to reach its planning speed.
7. Better Fuel Economy
Dual props also cause less drag and can offer lower planing speed.
They also help the boat to get on plane faster and hold on plane longer when decelerating.
All of these ensure less fuel consumption which means better gas mileage.
7 Disadvantages of a Dual Prop Drive
1. Costs
It’s safe to say that the biggest disadvantage of a dual prop drive systems is their significantly higher initial costs.
Two props cost more than one, while the special propulsion system of the props also means higher R&D and manufacturing costs.
All of these convert to higher purchase prices, which may discourage many buyers.
2. Fewer Aftermarket Props and Parts
Since dual prop drives and outboards are much less common, finding aftermarket parts for them can be a challenge.
Keep in mind that aftermarket props are not available for all dual prop systems!
3. Complexity
Complexity is another big flaw.
The more complex architecture of these systems not only means lower reliability but also converts to higher repair bills.
What’s more, if you damage the props you will have to buy two instead of one.
4. Corrosion
We also have to mention corrosion issues.
Due to their more complex design, certain dual prop drives are much more prone to rusting than their single-prop equivalents.
Because of this, if you want to keep your boat for the long run or if you are considering buying a used boat/outboard, you may want to stick to a single-prop model.
5. Slower Top Speed
The smaller diameter props of a dual prop system ensure faster acceleration but a slightly slower top speed.
The difference is not significant, but it’s also another factor you have to take into account.
6. Faster Idle Speed
While a dual prop boat is slower at top speed, it is typically faster at idle speed due to the better prop bite.
This doesn’t seem like a big issue until you have to slowly maneuver around docks and tight places.
The faster the boat moves at idle speed, and faster you will bump into the docks or other objects if something goes wrong.
7. Weight
Although this is not the biggest consideration on a 300+ HP boat, the second prop and its driving system add some extra weight to the propulsion.
Takeaways – FAQs About a Dual Prop Drive
As a takeaway, we’ve answered the most common questions on the topic!
Why do Some Outboards Have 2 Props?
Boat drive systems (typically for 300 HP engine power and up) are sometimes available with both single and dual prop configurations.
The latter makes sense, especially on larger (350-600 HP) outboards where the extra power could negatively affect handling.
The most common issues on high-power, single-prop outboards are the high steering torque, cavitation, and prop walk at lower speeds.
How Does a Dual Prop Drive Work?
Simply put, a dual prop drive system features two counter-rotating propellers.
The front prop is usually larger in diameter and features 3 or 4 blades depending on the model. In contrast, the rear prop is smaller and typically features 3 blades.
Is a Dual Prop Better Than a Single?
We cannot say that dual prop drive systems are better than their single-prop siblings, since each design has its pros and cons.
What are the Benefits of a Dual Prop Outboard?
In a nutshell, the key benefits of dual prop outboards and stern drives are as follows:
- Increased blade area
- Reduced steering torque
- More precise maneuverability
- No “prop walk”
- Less cavitation
- Faster acceleration
- Better fuel efficiency
What are the Disadvantages of a Dual Prop Outboard?
In return, the biggest flaws of dual prop outboards and stern drives are as follows:
- Higher initial costs
- Fewer aftermarket props and parts
- Complexity
- Corrosion
- Faster idle speed
- Slower top speed
- Heavier weight
When Was the First Dual Prop Introduced?
The fist dual prop drive was introduced in 1982 when Volvo Penta released its Duoprop system.
Mercury also entered the market in 1993 with the MerCuriser Bravo Three drive once the patent protection expired on Volvo’s Duoprop.
Regarding outboards, Yamaha tasted the market with its TRP (Twin Rotating Prop) outboards, which never became commercially successful.
Suzuki also released its first dual prop outboard, the dual prop DF300 in late 2017, followed by the DF350 model.
