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Old 16-11-2016, 18:18   #331
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Re: Oceanvolt Hybrid Motor

Quote:
SDChristian nailed it. The EP naysayers have a religious belief in their worldview and will defend it to the death ( as history has repeatedly shown unfortunately), and a serious lack of critical thinking on this topic. They repeatedly ignore what has been said that addresses their "concerns" much like the climate deniers do. It's a tactic of denialism and negativity, that is used to support their confirmation bias, which we ALL must be on guard against. Read "Merchants of Doubt" by Naomi Oreskes for a clinical exposure of this way of thinking. It reminds me of the beginnings of the cruising multihull "movement" when all the die-hard mono sailors took so much delight pointing out cases of capsized multi's while completely ignoring the sheer number of mono's at the bottom of the ocean and the resultant "lost at sea" statistics. Classic confirmation bias.
This is complete nonsense and philosophically bankrupt thinking.

EP naysayers have a SCIENTIFIC view based on critical thinking and examination of the laws of physics. In a similar manner most would support the concept of climate change as it is based on the majority scientific world view.

On the contrary EP evangelists are similar to climate deniers in that they twist claims from the minority view rather than provide substantive scientific or experiential facts to plead their case. When challenged they resort to arguments such as those above. Indeed they are the classic "deniers", and almost never respond when arguments are provided based on either the laws or thermodynamics or significant experience by those who have spent considerable time cruising the open ocean.

I have not met one EP skeptic who would defend his/her viewpoint to the death. In fact most are very open minded with a background based on solid engineering/scientific backgrounds.

I have not met one EP skeptic who would not rather have EP on his boat if it was economical and safe.

We all look forward to the time when EP becomes reality, and I think most accept that it will given the passing of time, but right now the vast majority of boats are fitted with diesels for good and sound scientific reasons.

Rob, I understand that it must be tiring for you to constantly have your view challenged by those of us who compose our views based on experience and science, but I am afraid that is simply the cross you have to bear by challenging the norm. I for one, hope it all works out for you and like many others before you do not suffer financial or physical harm as a result of your viewpoint on this matter.
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Old 16-11-2016, 18:36   #332
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Re: Oceanvolt Hybrid Motor

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Originally Posted by Just Another Sa View Post
There is no need for additional energy input, it's enough to reduce the losses already there, namely those from hull drag. Nothing to do with perpetual motion.
A boat doing 8 knots 50% of the time and 6 knots 50% of the time has greater average drag than the same boat doing 7 knots 100% of the time. There is the reduced losses.
In addition, if sailing directly downwind under spinnaker at 8 knots the boat is slowed down to 7 knots by electrical energy production, the apparent wind will increase providing more driving force from the sails. This might also increase propulsive power from the sails.
But,but, but, the incresed force on the sails is a product of increased drag from the generator. the increased pressure is identical to the force required to overcome the drag and propel the boat at 7knots. You are implying that the increased pressure might be available to increase boat speed. Not so.
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Old 16-11-2016, 18:55   #333
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Re: Oceanvolt Hybrid Motor

Big Breakie . It's time to put your money where your mouth is. I really don't want to hear any more of your conspiratorial aggression. Go and buy a boat, put in an electric motor, add a battery bank, add solar panels and/or a gennie and get out there. Ignore the significant number of people who have tried to give you advice and just do it. Report back to us when you've completed the project.
BTW there is a series of posts on C&F from a fellow who put electric on a houseboat a few months back. It might be worth reading it.
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Old 16-11-2016, 19:01   #334
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Re: Oceanvolt Hybrid Motor

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Originally Posted by transmitterdan View Post
BigBeakie,

If you want to convince the people who are too limited in their thinking then put some numbers with the arguments for EP. There aren't many numbers involved. If it is easy to make the case on an engineering basis then it turns to cost. So why not just lay out the engineering argument for why EP is equally as good as diesel/mechanical transmission for propulsion instead of claiming there is some kind of conspiracy against it. I can assure you there isn't such a conspiracy. Just as I believe there are probably not dozens of happy EP customers too shy to brag about it. Have you ever met anybody too shy to brag about their boat?
Thanks for your entirely reasonable response, and entirely reasonable request for justification.

When I have completed sea trails of our EP, I will have some direct experience and numbers to share for a 50' Lwl, 12.5:1 Lwl/Bh, 13 ton full displacement cat. The OceanVolt projection for that is 6.4 knots at 7kW. So I expect to burn 3.5 liters of diesel an hour on the DC genset alone to go 6.4 knots in mild sea state.In rougher sea state I expect the speed to drop to around 5 knots. But I can also use solar and battery to augment as required.

Yes, I have met EP owners who actively read the sort of obfuscation by the EP naysayers here, and actively decide not to participate. They are not out to change the world, they just love cruising with their new EP system. The tone of the "discussion" here sucks, frankly, and they don't want any part of it.

However what has been glossed over is that numbers have been put up, but they just get howled down and effectively we get accused of being liars, or evangelicals, or the EP vendors are snakeoil salesmen. If an OceanVolt "salesman" gets misquoted by a journalist and kaN becomes tons in a report of the Vendee Globe bollard pull test, then the EP vendor is guilty of hype. When you are told that boats can go at 7 knots using 7kW, then that is "obviously not true".

BTW, the OceanVolt projections for Conrad Colemans 60' IMOCA Class were 7.2 knots at 7kW, and that is what was achieved in reality. Another data point that the OceanVolt projection algorith is valuable. But that doesn't mean you can go 10 knots using 10 kW, because it is not straight line, we all know that. In fact for the IMOCA 60 to go 7.8 knots would take about 10kW!! so it is out of the sweet spot.

Coleman also got 4.5kW of power, yes that's not a typo or misquote or hype or a lie, it is what it is as logged by accurate calibrated instruments, 4.5 kilowatts of power on the OceanVolt regen across the Atlantic, so no, you do not need a rotating saildrive to get significant regen power.

Now, is there anything to discuss that would be of benefit for cruisers in any of this??
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Old 16-11-2016, 19:14   #335
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Re: Oceanvolt Hybrid Motor

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Originally Posted by dlymn View Post
Big Breakie . It's time to put your money where your mouth is. I really don't want to hear any more of your conspiratorial aggression. Go and buy a boat, put in an electric motor, add a battery bank, add solar panels and/or a gennie and get out there. Ignore the significant number of people who have tried to give you advice and just do it. Report back to us when you've completed the project.
BTW there is a series of posts on C&F from a fellow who put electric on a houseboat a few months back. It might be worth reading it.
Not surprisingly, you obviously have not read this thread. That is exactly what I am doing at this moment. See Posts 150 & 158.

I certainly do NOT ignore well intentioned advice such as from CWJOHM, whose heart is in the right place. Particularly from those who have direct experience to relate. What direct experience with EP do you have again, dylm???
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Old 16-11-2016, 19:38   #336
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Re: Oceanvolt Hybrid Motor

Quote:
When I have completed sea trails of our EP, I will have some direct experience and numbers to share for a 50' Lwl, 12.5:1 Lwl/Bh, 13 ton full displacement cat. The OceanVolt projection for that is 6.4 knots at 7kW. So I expect to burn 3.5 liters of diesel an hour on the DC genset alone to go 6.4 knots in mild sea state.In rougher sea state I expect the speed to drop to around 5 knots. But I can also use solar and battery to augment as required.
And this is the nub of the issue. For all of the stuff discussed here the whole question comes down to a few key issues.

The first has absolutely nothing to do with EP motors per se. Nobody denies they work and they generate the power stated. It has to do with the amount of power needed to cruise in the open ocean. You believe this is 7kW. I would not venture out to sea with EP motors any less than 30kW in a 50ft cat. This is based on actual 50ft cats that have used 20Kw EP motors and they had to be ripped out as they did not provide enough power in poor conditions. Nothing to do with the quality of the EP motors.

You state that all of this is overcome by having a suitable sailing cat and the appropriate sailing skills, but in fact several of the cases in point were fast cats with skippers with decades of sailing skills both in racing and cruising.

The second is that one generator will suffice, but in fact you lose a key component of twin diesels - redundancy. For EP to be safe you need generators on each EP motor plus a separate house generator.

The third is that you argue that you do not need large battery storage and therefore the long term savings in diesel justify the extra cost. However, with a small amount of battery storage your time motoring without generator is minimal and there is no way the financial equation works. All you have is inefficient pseudo diesel motors. In any case for safety you need at least one hour at full capacity 2 motors or 60 KW. The input from solar and hydro is negligeable in this equation.

By the time you equip all this cost and weight kills you.

So you know all this but you have done your numbers and it all comes down to a gamble that 7Kw will do the job. As I said some years ago this is easy to prove. Simply charter a fastish cat, work out the torque curves and limit the revs to 10Hp (7Kw), take her out in adverse seas and conditions, and see how it goes. At least you have the power backup if you need it, which you will not have should you equip 7Kw motors. I note that you have yet to undertake this obvious undertaking of proof.
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Old 16-11-2016, 20:15   #337
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Re: Oceanvolt Hybrid Motor

Quote:
Originally Posted by cwjohm View Post
This is complete nonsense and philosophically bankrupt thinking.

EP naysayers have a SCIENTIFIC view based on critical thinking and examination of the laws of physics. In a similar manner most would support the concept of climate change as it is based on the majority scientific world view.

On the contrary EP evangelists are similar to climate deniers in that they twist claims from the minority view rather than provide substantive scientific or experiential facts to plead their case. When challenged they resort to arguments such as those above. Indeed they are the classic "deniers", and almost never respond when arguments are provided based on either the laws or thermodynamics or significant experience by those who have spent considerable time cruising the open ocean.

I have not met one EP skeptic who would defend his/her viewpoint to the death. In fact most are very open minded with a background based on solid engineering/scientific backgrounds.

I have not met one EP skeptic who would not rather have EP on his boat if it was economical and safe.

We all look forward to the time when EP becomes reality, and I think most accept that it will given the passing of time, but right now the vast majority of boats are fitted with diesels for good and sound scientific reasons.

Rob, I understand that it must be tiring for you to constantly have your view challenged by those of us who compose our views based on experience and science, but I am afraid that is simply the cross you have to bear by challenging the norm. I for one, hope it all works out for you and like many others before you do not suffer financial or physical harm as a result of your viewpoint on this matter.
Chris, I hope you know that I truly do respect you and value your feedback, above others. I would like to have a structured, reasonable, point by point discussion with you, in writing, to explore your objections. We would use verifiable facts/data and evidence. Is this acceptable to you? We would use the vehicle of a separate thread just for us. No other comments will be entertained.

You have nothing to gain from it in the short term, other than intellectual satisfaction that you have proven me wrong. You have my assurance that if you prove to me that I am wrong, I will be convinced. I am not an evangelical in any sense. I will win if you are right because I would switch to 40HP Beta diesels which was always our plan B anyway. This will save me short term cash on capex, but give me long term higher costs in maintenance.

If however my evidence persuades you, you will be public in acknowledging so on this forum. I think it will be educational and important. Deal?
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Old 16-11-2016, 21:19   #338
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Re: Oceanvolt Hybrid Motor

Hi Chris,

"I would not venture out to sea with EP motors any less than 30kW in a 50ft cat. This is based on actual 50ft cats that have used 20Kw EP motors and they had to be ripped out as they did not provide enough power in poor conditions. "

Can I speak to the owners of any of these cats? Are they the Alibi cats? I need the specifics of their system, and the specifics of what constitutes "poor conditions".

Thanx
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Old 16-11-2016, 21:55   #339
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Re: Oceanvolt Hybrid Motor

Alibi 54, Tag 60, Corsair 51 in terms of performance cats. I am sure you are aware of the production cat stories.

Have no idea how to get in touch with them. I only get this information in passing, via owners, brokers or third parties. I do not believe it is reasonable to interrogate owners in detail in regard to what is obviously an embarrassing episode. For me it is sufficient information that they have replaced EP with Diesels and the general reasons why.

The Alibi design is laid out on their website.
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Old 16-11-2016, 22:26   #340
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Re: Oceanvolt Hybrid Motor

Once the zealots start referring to the realists as "denialists" and quote Merchants of Doubt, that says it all.

I'm out of here.
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Old 16-11-2016, 22:54   #341
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Re: Oceanvolt Hybrid Motor

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Originally Posted by BigBeakie View Post
Hi Chris,



"I would not venture out to sea with EP motors any less than 30kW in a 50ft cat. This is based on actual 50ft cats that have used 20Kw EP motors and they had to be ripped out as they did not provide enough power in poor conditions. "



Can I speak to the owners of any of these cats? Are they the Alibi cats? I need the specifics of their system, and the specifics of what constitutes "poor conditions".



Thanx

A handy tool here allows anyone to easily review a users past posts. You obviously enjoy having and hearing the same arguments over and over. You might fit right in at the kitchen table with my in-laws.

I prefer fly fishing, polishing brass, sailing and other quiet endeavors.
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Old 17-11-2016, 04:19   #342
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Re: Oceanvolt Hybrid Motor

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Originally Posted by SDChristian View Post
Elon Musk is not innovative? I mean going to Mars, privatizing NASA, and beating the top car manufacturers at their own game all at once is pretty unimpressive. You probably have done all that last week.
I will give credit where credit is due.
- He is very innovative at capturing tax breaks.
- He is very innovative at fooling people into investing.

I've yet to see any evidence he has been to Mars or taking over NASA. (didn't aliens blow up one of his rockets recently?)
Losing money year after year is hardly beating the top car manufacturers at their own game.

Again, the EP Cruising Boat proponents are about hope and dreams and I'm planning to buy one some day in the future and then I'll show you.

Again, start throwing some verifiable numbers out and prove us wrong.
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Old 17-11-2016, 04:50   #343
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Re: Oceanvolt Hybrid Motor

Slightly different topic but something I am confused about that relates to sizing the electric motor. I posted a video showing electric on one cat and diesel on the other in a tug of war. The 10kW electric pulled the diesel boat backwards with 22kW diesels, at wide open throttle on both boats. It wasn't faked and it was done by the charter company not those nasty snakeoil EP vendor.

I don't think there was a good explanation of how this occurs. There were responses that it was garbage video ( whatever that meant), or that tug of wars are completely irrelevant (of course that is true), and so on, but can anyone explain why this happened, especially since it is at WOT.

If it was at lower revs, say 25% power, then the high torque of the electric would out pull the diesel, I think that is agreed. But why does it still happen at WOT when the diesel would be at or near it's maximum torque?

An explanation in laymans terms would be good, without advanced math. On the face of it, it does seem that electric motors for propulsion can be sized at about half the equivalent kW rating and still generate the same, or better, thrust of the diesel.

I realise because they are not moving through the water as fast as they could without being tethered to each other that there is prop slippage & resultant loss of thrust efficiency, but that is true for both of them.

What gives?
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Old 17-11-2016, 05:15   #344
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Re: Oceanvolt Hybrid Motor

Boy you really have selective reading - I said it was a garbage video and provided an explanation. You're just not integrating any information that contradicts your viewpoint.

Electric motors develop peak torque at near 0 rpm - functionally instantaneous. Diesel engines need to get up to the right rpm. The video is garbage because it shows you the first 4 seconds from a standstill start - if you had any sort of connection remaining to this reality, you'll recognize that had they shown the video a mere 30 seconds later the diesel will be tugging the electric boat, then an hour later the electric boat will have zero propulsion remaining.

anyway - enjoy your fantasy. I truly hope battery technology matures to the point where this EP fantasy can come true. Unfortunately real world experience and real data (as opposed to cherry picked fantasy material) suggests otherwise.

I'm waiting for Yanmar to come out of a fictional fuel tank that carries 200 liters of diesel in 5 liter volume.

Anyway - I'm realizing that this isn't really educational and is more like trying to teach a pig to sing. It wastes your time and annoys the pig. Have a good one. Unsub.
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Old 17-11-2016, 05:15   #345
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Re: Oceanvolt Hybrid Motor

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Originally Posted by BigBeakie View Post
Slightly different topic but something I am confused about that relates to sizing the electric motor. I posted a video showing electric on one cat and diesel on the other in a tug of war. The 10kW electric pulled the diesel boat backwards with 22kW diesels, at wide open throttle on both boats. It wasn't faked and it was done by the charter company not those nasty snakeoil EP vendor.

I don't think there was a good explanation of how this occurs. There were responses that it was garbage video ( whatever that meant), or that tug of wars are completely irrelevant (of course that is true), and so on, but can anyone explain why this happened, especially since it is at WOT.

If it was at lower revs, say 25% power, then the high torque of the electric would out pull the diesel, I think that is agreed. But why does it still happen at WOT when the diesel would be at or near it's maximum torque?

An explanation in laymans terms would be good, without advanced math. On the face of it, it does seem that electric motors for propulsion can be sized at about half the equivalent kW rating and still generate the same, or better, thrust of the diesel.

I realise because they are not moving through the water as fast as they could without being tethered to each other that there is prop slippage & resultant loss of thrust efficiency, but that is true for both of them.

What gives?
1) I seriously doubt the "charter company" was neutral or they wouldn't be involved.
2) If you watch the video both boats were already moving in the direction of the electric boat meaning the diesel has to overcome both the electric drive and upwards of 20ton of boats moving in the opposite direction.
3) HP = torque * RMP. With electric producing max torque at zero RPM, the instantaneous HP from a standstill will be greater. This further exaggerates item 2 because while the prop on the electric boat is biting into clean water, the diesel has significant slippage because it is moving backwards.
4) The throttle lever may be wide open but because it's not moving forward, it might not be able to get up into it's power band like it would under normal conditions. Try it some time, if you tie the boat off to the dock and open her up, the diesel will typically be well below peak RPM.
5) They don't tell us what props were used. A large diameter low pitch prop on the electric boat vs a standard prop on the diesel would be like putting a 40hp tractor against a 400hp Ferrari. The Ferrari easily has more HP but the low gearing of the tractor will win every time in a tug-o-war.
6) As you said, a tug-o-war is irrelevant to the typical cruiser. Electric motors can do some things better. For acceleration, you can use a motor "rated" for lower HP, which to a degree is what the tug-o-war is showing. At cruising speed, HP is HP. It doesn't matter what the source is.

I could come up with more issues but I'm sure you will shoot it down as speculation. This is a perfect example of EP marketers giving partial information to give a false impression. They make claims and show a video supposedly supporting those claims but then they intentionally leave out a lot of key information.

Tesla does the same thing putting out videos of drag races. Electric motors are great for drag racing but do a 50 mile race around a track and you get totally different results because the test isn't optimized for electric motors.
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