These tests were put on by Volvo who sells these duo props. That is a lot of factors that are not covered in this report. Who tuned the props? For what RPM's were they tuned? How are they cuped? How dedicated was the "Single prop" driver? What AOA (Angle of Attack) were the IO's set? It is easy to believe that a duo prop would win in either low end hole shot or top speed, but both? How does it compare with twin engines vs single engines? What were the diameters of the props? What was the pitch of the props? I don't have a dog in this race. A lot of companies make duo prop systems, usually you get better hole shot with a duo prop but you give up top end. This video says you get both. I say something in this video is fixed.
So your argument is that duo props are to quicker to accelerate nor have a higher top end? You argue that more blades int he water doesn't create great grip? Your sill complaint is all the specs are tweak able and issue it wasn't done. If we were allowed to tweak the prop to the boat for the single would we not expect them to do the mods ideal to the duo? Duo is better in every way so I'm not sure what your point is!
@@cowlumbus Robert, I have done a lot of propeller testing, a lot. I hold four world records in boating. I believe duo props are better at some things, not everything. To my knowledge, NOT one major high speed race boat uses duo props. They may not all be as stupid as you think they are. There might be a reason.
@@CupRoyale They are faster up to about 55-60 mph...after that the law of diminishing returns comes into effect and the drag slows them down despite the increase in thrust. For recreational boats, dual prop is better in every way...acceleration, docking and control, fuel economy, etc.
@@virtual_warbirds I have tested way too many boat props and have been involved with the difference between a single prop and a duo prop on the exact same boat to believe that statement. We see the difference in much slower speeds than 55 mph. A duo prop gives much more low end torque, that costs you on the upper end of the power stroke OF THE MOTOR. It is not magic. Sorry I don't believe that a duo prop is always better. Sorry.
Great video thanks. One of my old friends had a boat like that. Unfortunately they were coming the inlet and hit a Chanel marker. I’m not sure what e weather conditions where.or who they were doing.RIP J.S AND M.W.
The problem here is that duoprop boats most definitely are slower at the top end; a second prop is a 100% drag increase (as far as props go)over a single prop. They're better for acceleration a d slow speedanuevering but... Duoprop are slower top speed, there's a reason they aren't on speed boats.
It depends... Most of the racing boats has one prop. At the same time many cruising boats get fgaster with Duoprops. Depend on boat type, rpm, type of the prop, speed of the boat etc.
A lot of factors come in to play, generally you have to make a choice as to what is most important to you. For top end speed you are better with one motor and one prop in an ideal world, that doesn't really exist. All motors have friction and energy losses and all props have energy losses and friction losses. Now how much the boat weighs, how much wet surface, and how fast do you want to accelerate. Better acceleration generally comes from better grip in the water which equates to more surface area of prop. Another issue that pops is torque losses. A single prop twists the boat and the water, because of this twisting there are more losses. So putting a second prop (duo) or a second motor comes to play. Realize both of them create new losses. However, they may give you more than they take, it is the boat owner and operator's choice. This video is hype. Duo props are sometimes better but not always. I hold four world records in boating and have done a lot of testing myself.
Because most of the racing boats uses semi-submerged props. The efficience factor is high when only blades touches the water. Valid for speeds above 50 knots.
@@vsevolod_gavrilov Yes, surface piercing props are a different game, also there are strict rules on formula race boats. Our 8.5m 4 berth cruiser is over 4 tonnes, VP duo is working fine.
Yee, Single prop (SP) drive was introduced in 1958, also known as Aquamatic. Patented Duoprop (3-4 blades combination) as sterndrive was introduced in 80s. Although the Duoprop as concept as such was known since 1900s...
![Outboard vs Sterndrive [ Inboard Outboard vs outboard ] Which is Best? why? Inboard vs outboard](/img/1.gif)
These tests were put on by Volvo who sells these duo props. That is a lot of factors that are not covered in this report. Who tuned the props? For what RPM's were they tuned? How are they cuped? How dedicated was the "Single prop" driver? What AOA (Angle of Attack) were the IO's set? It is easy to believe that a duo prop would win in either low end hole shot or top speed, but both? How does it compare with twin engines vs single engines? What were the diameters of the props? What was the pitch of the props? I don't have a dog in this race. A lot of companies make duo prop systems, usually you get better hole shot with a duo prop but you give up top end. This video says you get both. I say something in this video is fixed.
So your argument is that duo props are to quicker to accelerate nor have a higher top end? You argue that more blades int he water doesn't create great grip? Your sill complaint is all the specs are tweak able and issue it wasn't done. If we were allowed to tweak the prop to the boat for the single would we not expect them to do the mods ideal to the duo? Duo is better in every way so I'm not sure what your point is!
@@cowlumbus Robert, I have done a lot of propeller testing, a lot. I hold four world records in boating. I believe duo props are better at some things, not everything. To my knowledge, NOT one major high speed race boat uses duo props. They may not all be as stupid as you think they are. There might be a reason.
@@CupRoyale They are faster up to about 55-60 mph...after that the law of diminishing returns comes into effect and the drag slows them down despite the increase in thrust. For recreational boats, dual prop is better in every way...acceleration, docking and control, fuel economy, etc.
@@virtual_warbirds I have tested way too many boat props and have been involved with the difference between a single prop and a duo prop on the exact same boat to believe that statement. We see the difference in much slower speeds than 55 mph. A duo prop gives much more low end torque, that costs you on the upper end of the power stroke OF THE MOTOR. It is not magic. Sorry I don't believe that a duo prop is always better. Sorry.
I don't agree with you but the video does have a propaganda type feel because it's old
Thanks for sharing 🙏🏼🥰
This is not a fair comparison, the Guy in the Dual prop boat is wearing a red jacket, red is always faster.
Kinda makes ya wonder why duoprops haven't taken over the market over the last 30 years.
They have on the high end market. Duel counter rotating props are used on the Volvo ISP drives.
Norman D *IPS
They cost more.
I missed this duel in my original city!
Great video thanks.
One of my old friends had a boat like that. Unfortunately they were coming the inlet and hit a Chanel marker. I’m not sure what e weather conditions where.or who they were doing.RIP J.S AND M.W.
I love this! Bellisimo! 🤌🏻
The problem here is that duoprop boats most definitely are slower at the top end; a second prop is a 100% drag increase (as far as props go)over a single prop. They're better for acceleration a d slow speedanuevering but... Duoprop are slower top speed, there's a reason they aren't on speed boats.
Does anyone know what make and model of boat they are using in this video?
Is a Tullio Abbate 25
Italian Lake Como T Abbate
my question is out of context: is there difference in speed between, 2 engines 1 propeller? and 2 engines 2 propeller?
It depends... Most of the racing boats has one prop. At the same time many cruising boats get fgaster with Duoprops. Depend on boat type, rpm, type of the prop, speed of the boat etc.
ryan It’s probably just gears. My dad’s friend has a duoprop stern drive 22 ft, and it’s one engine with the gears to turn two props.
A lot of factors come in to play, generally you have to make a choice as to what is most important to you. For top end speed you are better with one motor and one prop in an ideal world, that doesn't really exist. All motors have friction and energy losses and all props have energy losses and friction losses. Now how much the boat weighs, how much wet surface, and how fast do you want to accelerate. Better acceleration generally comes from better grip in the water which equates to more surface area of prop. Another issue that pops is torque losses. A single prop twists the boat and the water, because of this twisting there are more losses. So putting a second prop (duo) or a second motor comes to play. Realize both of them create new losses. However, they may give you more than they take, it is the boat owner and operator's choice. This video is hype. Duo props are sometimes better but not always. I hold four world records in boating and have done a lot of testing myself.
mama mia, i wish i have one even sigle prop
Love the moustaches!
Why ?
Was this filmed in 1960? It looks like a movie from elementary school
Albert Adams ..1985....
Is it possible to change an inboard outboard alpha one single prop to a duel prop?
Not possible... you need a Bravo 3
Yes. It's possible.
Modify the hull
My skipjack has a Volvo duoprop
I'd love to see an updated version of this with the DPS-M outdrive and the FWD-B2 outdrive
The latest one is DPS-D, with Hydraulic clutch in upper gear (Silent shift). Works as well for FWD.
@@vsevolod_gavrilov what's the link?
Had Volvo Penta did a better job marketing it may of took off
Funny... ya think they're trying to sell duoprop... I think the red sweater was the secret.
Now switch the props and show us SP ahead of DP????? Fake if you don't!
Cool... Now show us how great the duoprop is in reverse.
I dont know of any race boats that use the duoprop system... Why is that?
Because most of the racing boats uses semi-submerged props. The efficience factor is high when only blades touches the water. Valid for speeds above 50 knots.
Because they’re slower.
@@vsevolod_gavrilov Yes, surface piercing props are a different game, also there are strict rules on formula race boats. Our 8.5m 4 berth cruiser is over 4 tonnes, VP duo is working fine.
they arent that much different, boat setup played ALOT to do with that display.. the trim angles tell the story..
Having had both types, albeit newer, the DUO makes for a heck of a lot better driving experience for me.
The Duoprop is hands down better than a single prop. There's no point for Volvo being bias or rigging the tests of their own product.
Put three props on and lets see
They must not get out much
1985? You sure it wasn't 1958? LOL
Yee, Single prop (SP) drive was introduced in 1958, also known as Aquamatic. Patented Duoprop (3-4 blades combination) as sterndrive was introduced in 80s. Although the Duoprop as concept as such was known since 1900s...