Yanmar re-enters 50hp Diesel outboard market with Neander!!!!

Wow, at last a replacement for the old Yanmar 28hp diesel OB.

Yanmar takes on global diesel outboard distribution from NEANDER - Yanmar Marine

NEANDER Outboard Engine : Neander Shark

What do you think..?

I wish we could purchase a NEANDER Shark Turbo Diesel outboard engine in the US.

Pura Vida said:

I wish we could purchase a NEANDER Shark Turbo Diesel outboard engine in the US.

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Ah, I didn't realise it doesn't comply with US regs; are you sure you can't import it from Europe?

I've sent off an email to get the price.

What do you think: 2x as much as a gasoline 50hp?

Have a look at the engineering: wtf!!!

Technology : Neander Shark

The key enabler for a dual crankshaft engine with a constrained piston movement by two con-rods with theoretically no piston side forces is provision for forgiveness towards tolerances, which can lead to off-design positions of the piston in its cylinder bore and unfavorable mechanical effects like scuffing, sticking or simply higher friction as the least bad of effethis

PS: I had to look at the photos to understand this....lol.

Neat stuff!!!

Ski in NC said:

Neat stuff!!!

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Sounds like a complicated solution to a simple problem: vibration .

What's wrong with a counter weigh/damper on the crank/flywheel?

Rustybarge said:

Sounds like a complicated solution to a simple problem: vibration .

What's wrong with a counter weigh/damper on the crank/flywheel?

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Increase weight??

rardoin said:

Increase weight??

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I think a standard 50hp gas outboard would be about 100-110kg, so 175kg for the diesel is pushing the limits on the transom of a planing hull designed for half the load.

I'm thinking you would need a redesigned hull to take the extra weight.

Maybe its designed for displ. Speeds?

Rustybarge said:

Sounds like a complicated solution to a simple problem: vibration .

What's wrong with a counter weigh/damper on the crank/flywheel?

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A two cylinder four stroke is an infernal machine. With two pistons moving together, firing is 360deg, but dynamic balance is HORRIBLE. Counterweights on the fw or crank can help, but they provide a rotating force, the piston force is linear along bore axis. Only way to cancel is to have a counter rotating balance shaft. Which these guys basically get with the two cranks.

Only thing with worse vibes is a single cyl, and not by much!!

Better balance can be had by a 180deg crank, with pistons moving opposite. But then firing order is 180deg/540deg which provides it's very own special flavor of shake at low rpm. Also sounds horrible. Sounds like a misfiring three cyl. And balance of the 180deg crank is better, but still sucks.

The Neander design looks like it has or nearly has perfect mechanical balance. Weights added to the CR cranks will act linear like the piston forces and should be able to nearly cancel.

I think also the low rpm shake from firing impulses is canceled too.

Maybe they could use this design for the snotty running four stroke two cyl gassers.

Only downside I see is cost. Low volume Euro stuff is expensive.

Ski in NC said:

A two cylinder four stroke is an infernal machine. With two pistons moving together, firing is 360deg, but dynamic balance is HORRIBLE. Counterweights on the fw or crank can help, but they provide a rotating force, the piston force is linear along bore axis. Only way to cancel is to have a counter rotating balance shaft. Which these guys basically get with the two cranks.

Only thing with worse vibes is a single cyl, and not by much!!

Better balance can be had by a 180deg crank, with pistons moving opposite. But then firing order is 180deg/540deg which provides it's very own special flavor of shake at low rpm. Also sounds horrible. Sounds like a misfiring three cyl. And balance of the 180deg crank is better, but still sucks.

The Neander design looks like it has or nearly has perfect mechanical balance. Weights added to the CR cranks will act linear like the piston forces and should be able to nearly cancel.

I think also the low rpm shake from firing impulses is canceled too.

Maybe they could use this design for the snotty running four stroke two cyl gassers.

Only downside I see is cost. Low volume Euro stuff is expensive.

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Thanks for your explanation; very interesting..

Here's a video showing the setup:

Counter weights on a single or 360 twin if heavy enough can counter Ballance for up and down but when the counter weights are thrown sideways (as in 90 or 270 degrees) there's nothing to the side to counter weight wise so most engineers compromise by giving the counter weight about 1/3 of a total up and down Ballance. Old Brittish twin cyl motorcycles were all (almost) w 360 cranks and were quite smooth to about 50% rpm max but terrible above that.

For a smooth engine I've thought a 90degree V3 w the single cyl side having a cyl about twice the size as the twin cyl side would be good. No counterweights required ... I think.

But this Yanmar twin connecting rod engine will be very widespread soon .. I think. The Pistons coming almost straight down on the crank pins is a wonderful new design. If they have it heavily patented they should make millions with it.

This would also work on a single cyl.

I'll bet these engines will show up on the new pocket trawler Ken Fickett is designing at Great Harbour.

The key enabler for a dual crankshaft engine with a constrained piston movement by two con-rods with theoretically no piston side forces is provision for forgiveness towards tolerances,

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Does this mean it will be built with hand tools in a country with the cheapest labor?

The big question is do we really need a expensive heavy hard to maintain 50hp diesel when we have so many cheap light 4 stroke petrol outboards that have a proven history ?

And as my late father would say DON'T mention the WAR

Ski in NC said:

This would also work on a single cyl.

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Ski,
What about torsional vibration?
This would be an engine w more crankshafts than cylinders?
gaston,
"Light 4 stroke gas ... " never heard that one before.

manyboats said:

Ski,
What about torsional vibration?
This would be an engine w more crankshafts than cylinders?
gaston,
"Light 4 stroke gas ... " never heard that one before.

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The Honda 50 is within a few kg of the Yamaha 50 2 stroke so yes light 4 stroke

gaston,
Yamaha is offering a 50hp 2 stroke?
Must be like the Evinrude E-tec. And they aren't light.
Only light OB is an old one.
I'll look up the Yamaha though.

Went to the Yamaha site and the only 50hp engine was SOHC and 249lbs or 113kg. The Yanmar diesel OB is 175kg.

manyboats said:

Ski,
What about torsional vibration?
This would be an engine w more crankshafts than cylinders?
gaston,
"Light 4 stroke gas ... " never heard that one before.

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Torsional vibes are an issue with long multi cylinder crankshafts. Crank flexes in the twisting sense, and has a natural frequency that can get excited by firing pulses. Not really an issue with few cylinders, the cranks are relatively stiff in the twisting sense.

But I do wonder about gear lash between the cranks, and how ever they extract the output. Guess one crank is driving output shaft, other is geared to the main, so a prime candidate for gear lash rattle.

Proof is in the pudding!! I'd love to see the details and fiddle with one. Some elegance seen in the casual glance!!

WHY a Diesel?

With many new fancy gas engines creating 14hp per gal/hr and diesel 15%+ more costly than gas why bother?

Surely you wont be up in the 1,000 - 2,000 hours of operation per year that might justify a diesel?

The really long head bolts which go right down to the casing are unique as well.

I'll have to read the spaceballs thing a few more times through.

FF said:

WHY a Diesel?

With many new fancy gas engines creating 14hp per gal/hr and diesel 15%+ more costly than gas why bother?

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At wot, there is no outboard that produces 14 hp per gph. The best I have seen is 12 and a lot of them are less than 11. The Yanmar diesel should do 20 as it is a small displacement (for 50 hp), turbo charged, common rail. That is a 67% improvement over the best gas outboard.

I agree that it will take a lot of hours to justify it based on fuel usage. It all depends on price, but as Ski said low volume high tech manufacturing is expensive.

David

FF said:

WHY a Diesel?

With many new fancy gas engines creating 14hp per gal/hr and diesel 15%+ more costly than gas why bother?

Surely you wont be up in the 1,000 - 2,000 hours of operation per year that might justify a diesel?

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Why buy a diesel car? Same reasons.

Spy the long bolts could stretch.

Ski (re your #19) you mean one cyl engines have no torsional vibration? I would think one cyl engines would have max torsional vibration. Looks like I may not know what it is.

FF said:

WHY a Diesel?

With many new fancy gas engines creating 14hp per gal/hr and diesel 15%+ more costly than gas why bother?

Surely you wont be up in the 1,000 - 2,000 hours of operation per year that might justify a diesel?

Click to expand...

Handy not to have to carry gasoline onboard for an outboard.

Could make a standby engine for a trawler: bolt a jack plate onto the transom and drop on the diesel OB....

manyboats said:

Spy the long bolts could stretch.

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I would imagine they are torque to yield fasteners with a hard head gasket to get maximum sealing.

Rustybarge said:

Handy not to have to carry gasoline onboard for an outboard.

Could make a standby engine for a trawler: bolt a jack plate onto the transom and drop on the diesel OB....

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Yep, no longer have to carry gas that goes boom on the boat and you have a common fuel for the trawler and outboard. With the common fuel you now have a workable, sorta, backup engine.

Later,
Dan

manyboats said:

Why buy a diesel car? Same reasons.

Spy the long bolts could stretch.

Ski (re your #19) you mean one cyl engines have no torsional vibration? I would think one cyl engines would have max torsional vibration. Looks like I may not know what it is.

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Long bolts and short bolts stretch to get the clamping force. Long bolts actually easier to deal with as clamping force as clamped parts heat and cool. Bolts are really just stiff springs.

Torsional vibration usually refers to a shaft like a crankshaft twisting and acting like a spring doing it. That's why straight sixes have the "torsional damper" on the nose. Absorbs energy from the twisting vibration. Short cranks have no such issue.

But low cylinder count engines have another issue that is not really "torsional vibration". I'm not sure what is the best term, but "unsteady rotational speed" seems to fit. The engine speeds up and slows down with firing and compression, and this applies shake to the engine structure, rattles the boat, and rattles whatever is being driven.

Looks like the Neander will still have unsteady rotational speed, but the CR cranks will prevent the engine itself from shaking. Whether 1, 2, or more cyl. But not 100% on how it will behave. A big part is if there is one or two flywheels and what their inertia is. If different, engine will still shake.

Thanks Ski,
So that's why they call the "torsional"vibration dampener "torsional". And then there's torsion bar suspension .. think Crysler products (50s).
I thought the jerking unsteady rotational movements of rotational parts connected to the crankshaft and the crankshaft itself was torsional vibration. The effects can be clearly seen on gravel or a beach where a motorcycle rear wheel "scratches" or looses traction when the abrupt torque of a single cylinder fires. I'll be looking for a word or perhaps a pair of words to express that.

I once had an inline 3 cyl motorcycle (4 stroke) that had a gear driven flywheel that rotated opposite of the crankshaft. There was none of the sideways or torque rotational movement of a normal motorcycle w an inline (w the wheels) crankshaft .. think BMW or Goldwing. Flywheels rotating opposite the crankshaft has a profound effect on vibration .. or lack of it. With this 3cyl motorcycle I could go 70mph or more for miles not being in top gear. Sometimes I'd be cruising down the highway .. Look down at the gear position indicator and see that I was in 4th and not 5th.

But the big plus w this Yanmar twin is the near vertical thrust direction from piston pin to crankpin. That should bring about large increases in efficiency and even larger life to pistons. And perhaps less need for high viscosity in the lube oil.
Some engines in the past have had cylinder bores slightly offset to reduce side thrust and have a better mechanical advantage but nothing like this Yanmar. I'm in awe of Yanmar for developing such a monumental breakthrough. Off the top that's what it seems to be. Does anyone know any different?

Ski, the term I think you are looking for is "torque ripple." All motors have torque ripple, some configurations more than others, depending on RPMs and throttle position/load.

This is different from the torsional vibration as you likely know, that depends on the inertia and stiffness of the drivetrain and the excitation from power stroke events.

For example, a Harley big twin (45 degree Vtwin) can generate a torque ripple of 600 ft-lbs (or more) at the crank, hence the need for primary end torque devices. Diesels have relatively large fluctuations in torque as well, but that is designed for and is part of why all the rotational and up/down stuff is heavy.

I think this new motor is pretty cool for boats up to a certain size. I recall seeing some Devlin Design boats with OB's in this HP range that were spacious for their length and got good range/milage too.

Edit: OK, after reading closer, I think what they are referring to here is that the twin crank/rod design allows them to design out the forces that cause an outboard to try to rotate around its steering axis, which would be really nice to have and would really smooth out the power delivery and forces/vibration applied to the transom.

The proof is in the pudding!!!

They should send me one and I will test it and report back!!