26/08/2026
Rightโฆ
Iโm sure some of you have seen one of these things hanging off the back of a boat before.
You walk past the transomโฆ
Look downโฆ
And immediately think:
โ๐ฆ๐ต๐ถ๐, ๐๐ต๐ ๐ต๐ฎ๐ ๐๐ต๐ถ๐ ๐ผ๐ธ๐ฒ ๐ด๐ผ๐ ๐ง๐ช๐ข ๐ฝ๐ฟ๐ผ๐ฝ๐ฒ๐น๐น๐ฒ๐ฟ๐ ๐ผ๐ป ๐ผ๐ป๐ฒ ๐บ๐ผ๐๐ผ๐ฟ?โ
Because letโs be honest.
Before you know what it does, it already looks windgat.
One Suzuki 350.
One leg.
Two shiny stainless props sitting one behind the other like the motor has arrived at the dam wearing two Rolexes.
But they arenโt there because some engineer thought:
โ๐ฌ๐ผ๐ ๐ธ๐ป๐ผ๐ ๐๐ต๐ฎ๐ ๐๐ผ๐๐น๐ฑ ๐น๐ผ๐ผ๐ธ ๐น๐ฒ๐ธ๐ธ๐ฒ๐ฟ ๐ผ๐ป ๐๐ป๐๐๐ฎ๐ด๐ฟ๐ฎ๐บ?โ
Thereโs actually some very clever engineering happening underneath that gearbox.
And once you understand what those two props are doingโฆ
You start realising why heavy boats absolutely love them.
๐๐ถ๐ฟ๐๐๐น๐โฆ ๐๐โ๐ ๐ก๐ผ๐ ๐ง๐๐ผ ๐๐ป๐ด๐ถ๐ป๐ฒ๐
Letโs clear that up.
A dual-prop outboard is still:
One motor.
One gearbox.
One throttle.
One leg.
But on the prop shaft youโve got ๐๐๐ผ ๐ฝ๐ฟ๐ผ๐ฝ๐ฒ๐น๐น๐ฒ๐ฟ๐ ๐๐ถ๐๐๐ถ๐ป๐ด ๐ผ๐ป๐ฒ ๐ฏ๐ฒ๐ต๐ถ๐ป๐ฑ ๐๐ต๐ฒ ๐ผ๐๐ต๐ฒ๐ฟ, ๐ฟ๐ผ๐๐ฎ๐๐ถ๐ป๐ด ๐ถ๐ป ๐ผ๐ฝ๐ฝ๐ผ๐๐ถ๐๐ฒ ๐ฑ๐ถ๐ฟ๐ฒ๐ฐ๐๐ถ๐ผ๐ป๐.
Technically, the correct word is ๐ฐ๐ผ๐ป๐๐ฟ๐ฎ-๐ฟ๐ผ๐๐ฎ๐๐ถ๐ป๐ด.
Counter-rotating usually refers to two separate propellers on two separate shafts, like twin engines spinning opposite directions.
Contra-rotating means both props share the same axis.
Nowโฆ
Will I correct every oke at the slipway who says counter-rotating?
Absolutely not.
Life is too short.
We all know what Frikkie means.
๐ฆ๐ผ ๐ช๐ต๐ ๐ง๐ต๐ฒ ๐๐ฒ๐น๐น ๐๐ผ ๐ฌ๐ผ๐ ๐ก๐ฒ๐ฒ๐ฑ ๐ง๐๐ผ?
Because a normal propeller is actually wasting some of your expensive petrol.
Ja.
Sorry.
Every time your single propeller spins, it doesn't only throw water backwards.
It also spins the water.
Think of the wake behind the prop like a corkscrew.
Some of the engineโs energy is being used to create that swirling water instead of simply pushing the boat forward.
Thatโs lovely if your goal is to make the Vaal Dam rotate slightly faster.
Not particularly useful if youโre trying to move the boat.
So engineers had a clever idea:
๐ฆ๐๐ถ๐ฐ๐ธ ๐ฎ๐ป๐ผ๐๐ต๐ฒ๐ฟ ๐ฝ๐ฟ๐ผ๐ฝ ๐ฏ๐ฒ๐ต๐ถ๐ป๐ฑ ๐๐ต๐ฒ ๐ณ๐ถ๐ฟ๐๐ ๐ผ๐ป๐ฒ ๐ฎ๐ป๐ฑ ๐บ๐ฎ๐ธ๐ฒ ๐ถ๐ ๐๐ฝ๐ถ๐ป ๐๐ต๐ฒ ๐ผ๐๐ต๐ฒ๐ฟ ๐๐ฎ๐.
The first prop creates the swirl.
The second prop arrives behind it, grabs some of that rotational energy and straightens it back out into useful thrust.
Basicallyโฆ
The first prop makes a mess.
The second prop cleans up after it.
Like every marriage...
๐๐๐ ๐ง๐ต๐ฒ ๐ฅ๐๐๐ ๐๐ฑ๐๐ฎ๐ป๐๐ฎ๐ด๐ฒ ๐๐ ๐๐ฟ๐ถ๐ฝ
This is where dual props become properly interesting.
A single prop only has so much blade area available.
Eventually, as horsepower increases and boats get heavier, you reach a point where the poor propeller is being asked to transfer an enormous amount of power into the water through three or four blades.
And water isn't a road.
You can't just keep adding horsepower and expect the tyres to hook.
At some point the prop starts slipping, ventilating or struggling to put all that torque down.
So instead of making one enormous propeller and hanging a gearcase the size of a JoJo tank underneath the motorโฆ
You add another prop.
Now you've effectively got six or seven blades biting the water.
Much more blade area.
Much more grip.
And that is why dual-prop owners often describe the difference as going from ๐๐๐ผ-๐๐ต๐ฒ๐ฒ๐น ๐ฑ๐ฟ๐ถ๐๐ฒ ๐๐ผ ๐ณ๐ผ๐๐ฟ-๐๐ต๐ฒ๐ฒ๐น ๐ฑ๐ฟ๐ถ๐๐ฒ.
The boat doesn't suddenly have more horsepower.
It just becomes much better at using the horsepower it already has.
๐ง๐ต๐ฒ ๐ก๐๐บ๐ฏ๐ฒ๐ฟ๐ ๐๐
๐ฝ๐น๐ฎ๐ถ๐ป ๐ช๐ต๐ ๐๐ ๐๐ฒ๐ฒ๐น๐ ๐ฆ๐ผ ๐๐ถ๐ณ๐ณ๐ฒ๐ฟ๐ฒ๐ป๐
A normal single prop can typically operate with somewhere around ๐ดโ๐ญ๐ฎ% ๐๐น๐ถ๐ฝ.
A contra-rotating setup can bring that down closer to roughly ๐ฐโ๐ฒ% in the right application.
Which doesn't sound terribly excitingโฆ
Until you drive it.
Because suddenly:
The boat jumps onto plane.
It grips harder in a turn.
It can hold plane at lower speeds.
Load the boat with people, fuel, ice and fishing gear and it still gets its arse out of the water.
Punch it in ugly water and it doesn't immediately blow the prop loose.
That's where you understand the point.
It isn't necessarily:
โThis motor makes the boat 30km/h faster.โ
It's more:
โThis motor actually feels like it owns the water.โ
๐๐ป๐ฑ ๐ง๐ต๐ฒ๐ป ๐ง๐ต๐ฒ๐ฟ๐ฒโ๐ ๐ง๐ผ๐ฟ๐พ๐๐ฒ ๐ฆ๐๐ฒ๐ฒ๐ฟ
Anyone who's driven a powerful single-prop setup knows the feeling.
You accelerate hardโฆ
And the steering wheel suddenly develops political opinions.
The propeller is spinning one direction, and that creates a rotational force that can push or pull the boat slightly off line.
With two props spinning opposite directions, those forces largely cancel each other.
One says:
โLeft.โ
The other says:
โNee fok, right.โ
And the boat goes straight.
That becomes particularly nice on a big single-engine boat.
Less fighting with the steering.
Less torque reaction.
More of the thrust simply goes where you actually pointed the bow.
๐ช๐ต๐ผ ๐๐ฐ๐๐๐ฎ๐น๐น๐ ๐ ๐ฎ๐ธ๐ฒ๐ ๐ง๐ต๐ฒ๐บ?
Here's the surprising part.
In the current outboard market, according to the material we've pulled together, the proper factory dual-prop list is basically:
Suzuki.
Andโฆ
Mercury.
That's it.
Suzuki really brought the idea into mainstream modern outboards when it launched the DF350A in 2017.
Then Mercury walked into the room in 2021 and said:
โ๐๐๐๐ฒ.โ
And launched a ๐ณ.๐ฒ-๐น๐ถ๐๐ฟ๐ฒ ๐ฉ๐ญ๐ฎ ๐ฒ๐ฌ๐ฌ๐๐ฃ ๐ฉ๐ฒ๐ฟ๐ฎ๐ฑ๐ผ with contra-rotating props, a two-speed automatic gearbox and a gearcase that turns while the bloody powerhead stays facing forward.
Because apparently somewhere in America, a normal 600HP outboard wasn't complicated enough.
And now Mercury has even shown an ๐ด๐ฌ๐ด๐๐ฃ ๐ฉ๐ญ๐ฎ ๐ฐ๐ผ๐ป๐ฐ๐ฒ๐ฝ๐ using the same basic dual-prop philosophy.
At that point we're no longer discussing outboards.
We're discussing offshore power stations.
๐๐๐ ๐ฌ๐ฎ๐บ๐ฎ๐ต๐ฎ ๐๐ฐ๐๐๐ฎ๐น๐น๐ ๐๐ผ๐ ๐ง๐ต๐ฒ๐ฟ๐ฒ ๐๐ฎ๐ฟ๐น๐ถ๐ฒ๐ฟ
Here's a fun bit of boating history.
Yamaha had its ๐ง๐ฅ๐ฃ โ ๐ง๐๐ถ๐ป ๐ฅ๐ผ๐๐ฎ๐๐ถ๐ป๐ด ๐ฃ๐ฟ๐ผ๐ฝ๐ฒ๐น๐น๐ฒ๐ฟ setup years ago on 150HP two-strokes.
And the guys who used them absolutely loved them, particularly on shallow-water boats where hole shot mattered more than anything else.
Yamaha eventually moved away from offering it as a mainstream factory setupโฆ
But the idea never completely disappeared.
There are still people fitting TRP gearcases to certain Yamaha motors because apparently some fishermen refuse to let a good idea die.
Which, to be fairโฆ
Is basically how the entire boating industry works.
๐๐ป๐ฑ ๐ง๐ต๐ฒ ๐๐ฑ๐ฒ๐ฎ ๐๐ ๐ช๐๐ฌ ๐ข๐น๐ฑ๐ฒ๐ฟ ๐ง๐ต๐ฎ๐ป ๐ข๐๐๐ฏ๐ผ๐ฎ๐ฟ๐ฑ๐
Contra-rotating propellers aren't some new 2020s invention.
We're talking about an idea going back to the 1800s.
It later became common in aircraft and torpedoes.
Torpedoes especially benefit because if you put one big propeller on the back, the bloody thing wants to rotate itself in the opposite direction.
Two props spinning against each other cancel that torque.
Then Volvo Penta brought the concept properly into recreational boating with ๐๐๐ผ๐ฃ๐ฟ๐ผ๐ฝ ๐ถ๐ป ๐๐ต๐ฒ ๐ฒ๐ฎ๐ฟ๐น๐ ๐ญ๐ต๐ด๐ฌ๐.
Sterndrives have been using versions of the idea for decades.
So Suzuki didn't invent the physics.
What Suzuki did brilliantly was make it practical on a modern high-horsepower outboard.
๐ง๐ต๐ฒ๐ฟ๐ฒ ๐๐, ๐จ๐ป๐ณ๐ผ๐ฟ๐๐๐ป๐ฎ๐๐ฒ๐น๐, ๐ข๐ป๐ฒ ๐ฆ๐บ๐ฎ๐น๐น ๐ฃ๐ฟ๐ผ๐ฏ๐น๐ฒ๐บโฆ
Rocks.
Because rememberโฆ
You now have ๐๐๐ผ ๐ฒ๐
๐ฝ๐ฒ๐ป๐๐ถ๐๐ฒ ๐๐๐ฎ๐ถ๐ป๐น๐ฒ๐๐-๐๐๐ฒ๐ฒ๐น ๐ฝ๐ฟ๐ผ๐ฝ๐ฒ๐น๐น๐ฒ๐ฟ๐.
Hit something with a normal motor?
Congratulations.
You damaged a prop.
Hit something properly with a dual-prop setup?
Congratulations.
You may have damaged ๐๐ต๐ฒ ๐ฝ๐ฟ๐ผ๐ฝ๐ฒ๐น๐น๐ฒ๐ฟ๐.
Plural.
And they aren't identical.
Front prop.
Rear prop.
Different sizing.
Matched sets.
You don't just walk into the shop and say:
โ๐๐ถ๐๐ฒ ๐บ๐ฒ ๐ฎ๐ป๐ผ๐๐ต๐ฒ๐ฟ ๐ฎ๐ญ-๐ฝ๐ถ๐๐ฐ๐ต, ๐ฏ๐ฟ๐.โ
This can become a very expensive little conversation very quickly.
If you spend your weekends driving through shallow rocky water where propellers are basically considered consumablesโฆ
Dual prop might not be the relationship for you.
๐๐ป๐ฑ ๐ฌ๐ฒ๐โฆ ๐ง๐ต๐ฒ๐ฟ๐ฒโ๐ ๐ ๐ผ๐ฟ๐ฒ ๐๐ผ๐ถ๐ป๐ด ๐ข๐ป ๐๐ป๐๐ถ๐ฑ๐ฒ ๐ง๐ต๐ฒ ๐๐ฒ๐ฎ๐ฟ๐ฏ๐ผ๐
Two concentric prop shafts.
More bearings.
More seals.
More engineering.
More things living in a very small metal tube underwater while 350HP tries to escape through it.
So naturally, there's more complexity.
That doesn't mean they're unreliable.
But it does mean I would want a proper dealer and someone who actually understands the system looking after it.
This isn't the lower unit you take to Uncle Piet because:
โHe used to work on Johnsons in the 90s.โ
Especially on these high-horsepower modern setups.
๐ง๐ต๐ฒ๐โ๐ฟ๐ฒ ๐๐น๐๐ผ ๐ก๐ผ๐ ๐๐๐๐ผ๐บ๐ฎ๐๐ถ๐ฐ๐ฎ๐น๐น๐ ๐๐ฒ๐๐๐ฒ๐ฟ ๐๐ผ๐ฟ ๐๐๐ฒ๐ฟ๐ ๐๐ผ๐ฎ๐
This is important.
Dual props aren't some magical upgrade where two is always better than one.
If you're running a heavy centre consoleโฆ
Big cat.
Pontoon.
Heavy fishing boat.
Loaded offshore rig.
Something where grip, acceleration, stern lift and low-speed control matterโฆ
They make a hell of a lot of sense.
If you're chasing absolute top speed on a lightweight performance hull?
Different story.
In fact, Mercury's proper performance monsters like the 450R and 500R still use single props.
Why?
Drag.
At very high speed, the goal changes.
You want as little gearcase and propeller in the water as possible.
Dual props are about grip...
Single performance props are about reducing drag and going very, very fu***ng fast.
Different tools.
๐๐ป๐ฑ ๐๐ผ๐ฟ ๐ง๐ต๐ฒ ๐๐ฎ๐๐๐ฒ๐ป๐ด ๐ข๐ธ๐ฒ๐โฆ ๐๐น๐๐ถ๐๐๐ฑ๐ฒ ๐ฆ๐๐ถ๐น๐น ๐ฅ๐๐ถ๐ป๐ ๐๐๐ฒ๐ฟ๐๐๐ต๐ถ๐ป๐ด
Another South African problem.
You buy your lekker DF350.
Boat runs beautifully at the coast.
Then you tow it back to Harties or the Vaal.
Suddenly it doesn't quite pull the same revs.
Welcome to altitude.
Naturally aspirated engines lose power as elevation increases because there's less oxygen available.
So how you prop your boat at Durban sea level may not be how you want it propped at roughly 1,200โ1,500 metres inland.
Pitch matters.
Load matters.
RPM matters.
Where you actually use the boat matters.
That sexy pair of props is not:
One size fits all, thank you very much.
Proper propping is still one of the biggest differences between a boat that feels incredible and one where everyone says:
โI expected more from 350HP.โ
๐ฆ๐ผ ๐ช๐ผ๐๐น๐ฑ ๐ ๐ช๐ฎ๐ป๐ ๐ข๐ป๐ฒ?
On the right boat?
Absolutely.
There's something deeply satisfying about the idea.
Instead of simply making the engine bigger and bigger, engineers figured out a better way to get that power into the water.
More grip.
Less slip.
Harder hole shot.
Better reverse.
Better tracking.
More control with a heavy load.
Andโฆ
Let's not lie to ourselvesโฆ
It looks really cool.
Two big stainless props stacked behind a 350HP Suzuki just looks like something serious is happening.
You could explain swirl recovery, torque cancellation and blade loading to me all afternoon.
I'm still going to look at it and think:
โJaโฆ that's windgat.โ
๐ก๐ผ๐ ๐ ๐ช๐ฎ๐ป๐ ๐ง๐ผ ๐๐ฒ๐ฎ๐ฟ ๐๐ฟ๐ผ๐บ ๐ฌ๐ผ๐ ๐ข๐ธ๐ฒ๐โฆ
Who's actually driven a dual-prop outboard?
Not seen one.
Not watched a YouTube video.
Actually spent time behind one.
Did you notice the difference in hole shot?
Reverse?
Handling?
Loaded performance?
Would you pay the extra money and accept the extra complexity?
Or are you firmly in the:
โOne motor, one prop, less kak to breakโ
camp?
