Oceanvolt Hybrid Motor

[BigBeakie]

Guys, you asked for data from a real boat, and you just got it. And as predicted, now you are looking for any possible reason why the data is faulty, not good enough, not detailed enough, not to be trusted etc etc etc. How very predictable😂

You may think I'm a liar, and now on an open forum you have called me a liar in public. I will make another prediction right here and now that goes to your character. It is that when you are proven wrong by the hard data that will be released, you will not offer a sincere apology in public and admit you were wrong, all along.

I will publish data from our boat when it is launched, tested under adverse conditions.

By the way the skipper of this Schionning reported upwind motoring against 18 knots with NO drop in speed. Is that definitive? No. Is it conclusive? No. Is that double blind, independently verified data? No. It is only indicative, but somewhat valuable, nonetheless.




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[transmitterdan]

Originally Posted by SDChristian

Isn't the top motoring speed of a Lagoon 620 10 knots? Tough crowd.



Lagoon 620 (2012) - Asia-Pacific Boating

That boat displaces 3 times the 11T of the one with electric motors if I have understood the specs.

[SDChristian]

Originally Posted by transmitterdan

That boat displaces 3 times the 11T of the one with electric motors if I have understood the specs.

And yet 10 knots is good enough for that boat, but unsatisfactory for this one. Remember, we are talking about sail boats here, right? It's like there is pathological need for this system to fail.

[cwjohm]

I have no reason to doubt the numbers. To be fair this boat is the perfect candidate for electric motors. Tony has a fairly unique requirement of having a boat which is racing competitive (i.e. as light as humanly possible) and can passage from Gold Coast to Hammo in a relatively safe fashion. Note from the pictures that everything is carbon fibre including the toilets. When he first envisaged the boat he was going to install outboards but eventually opted for oceanvolt.


This is, however, a fairly unique case. It is not a cruising boat, it is a racing boat, and I doubt Tony will ever take is over 200nm offshore. Certainly, from my discussions with him he never took Kato into any rough stuff.


Further, with Tony's connections I very much doubt he paid retail for this kit.


I would think that drawing any conclusions from this to normal cruising yachts would be misleading. A bit like comparing a formula 1 to the average falcon.

[44'cruisingcat]

Originally Posted by SDChristian

And yet 10 knots is good enough for that boat, but unsatisfactory for this one. Remember, we are talking about sail boats here, right? It's like there is pathological need for this system to fail.

Don't you think there is a need for a system to justify it's cost?

[SDChristian]

Originally Posted by 44'cruisingcat

Don't you think there is a need for a system to justify it's cost?

Oh certainly! But the comment I was responding to only referenced the metric of speed; which was posited as bad, even though it is in fact quite standard.

[44'cruisingcat]

Originally Posted by SDChristian

Oh certainly! But the comment I was responding to only referenced the metric of speed; which was posited as bad, even though it is in fact quite standard.

So if a system costs twice as much, yet delivers half the performance, what's the benefit?

Fuel economy? How long till the fuel savings pay the difference? 30 years? 50?

[BigBeakie]

Originally Posted by cwjohm

I have no reason to doubt the numbers. To be fair this boat is the perfect candidate for electric motors. Tony has a fairly unique requirement of having a boat which is racing competitive (i.e. as light as humanly possible) and can passage from Gold Coast to Hammo in a relatively safe fashion. Note from the pictures that everything is carbon fibre including the toilets. When he first envisaged the boat he was going to install outboards but eventually opted for oceanvolt.


This is, however, a fairly unique case. It is not a cruising boat, it is a racing boat, and I doubt Tony will ever take is over 200nm offshore. Certainly, from my discussions with him he never took Kato into any rough stuff.


Further, with Tony's connections I very much doubt he paid retail for this kit.


I would think that drawing any conclusions from this to normal cruising yachts would be misleading. A bit like comparing a formula 1 to the average falcon.

Well actually Tony is about to head off across the Pacific and well offshore of 200 miles from what I've heard. So much for it not being a cruising boat. I've been on the boat and it is has a very comfy interior, beautifully appointed. Congrats due to Noosa Marine for the build quality, it is a sweet boat.

And not a racing pipe berth is sight

[SDChristian]

Originally Posted by 44'cruisingcat

So if a system costs twice as much, yet delivers half the performance, what's the benefit?

Fuel economy? How long till the fuel savings pay the difference? 30 years? 50?

That's a very subjective question. Everyone values different things. Add to that, we don't know the fuel savings. But lets not let an unknown number of unknown variables get in the way of jumping to uninformed conclusions! Cheers.

[44'cruisingcat]

Originally Posted by SDChristian

That's a very subjective question. Everyone values different things. Add to that, we don't know the fuel savings. But lets not let an unknown number of unknown variables get in the way of jumping to uninformed conclusions! Cheers.

Check the punctuation. See the question marks?

They indicate questions, not conclusions.

Informed questions though. Our fuel expenditure is less than $1000 per year, cruising full time.

So in our case, even assuming a hybrid system used NO fuel it would still take several decades to break even, if ever.

[StuM]

Originally Posted by SDChristian

Isn't the top motoring speed of a Lagoon 620 10 knots? Tough crowd.

Lagoon 620 (2012) - Asia-Pacific Boating

Since the Lagoon 620 has three times the displacement of Kator for roughly the same length, that's hardly surprising.

[Stumble]

Originally Posted by BigBeakie

Guys, you asked for data from a real boat, and you just got it. And as predicted, now you are looking for any possible reason why the data is faulty, not good enough, not detailed enough, not to be trusted etc etc etc. How very predictable😂

You may think I'm a liar, and now on an open forum you have called me a liar in public. I will make another prediction right here and now that goes to your character. It is that when you are proven wrong by the hard data that will be released, you will not offer a sincere apology in public and admit you were wrong, all along.

I will publish data from our boat when it is launched, tested under adverse conditions.

By the way the skipper of this Schionning reported upwind motoring against 18 knots with NO drop in speed. Is that definitive? No. Is it conclusive? No. Is that double blind, independently verified data? No. It is only indicative, but somewhat valuable, nonetheless.




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If you prove it I will eat my words publically and become an advocate for the system happily. But the problem I have is the numbers you are indicating indicates you are getting better speed out of a 6hp (at the shaft) output motor on a 11ton Catamaran than I actually saw on a 30' 3,500lbs monohull.

I have a very hard time believing this.

[BigBeakie]

Yes, I understand your incredulity. I've never asked anyone to believe anything without evidence, and never will. But there is such a thing as naive scepticism.

I will try and get screenshots of the MFD and OV screen which shows simultaneous readings.

There will be a big write up in Multihulls mags.


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[Just Another Sa]

Originally Posted by Stumble

Torquedo who i don't trust) reports a propulsion efficiency of about 55%, meaning 1kw in, 550w at the shaft. Getting 8kn from 8kw output is pretty hard to believe, but getting 8kn from 4.4kw at the shaft is pretty much impossible.

Assuming this is true you could also prove it by attaching a 6hp high thrust outboard and you should get the same 8kn.

That has nothing to do with propulsive efficiency.
55% propulsive efficiency means that for a kW at the shaft, thrust * boat speed = 550 W

If the voltage at the motor terminals is U, and the current in the wires at the terminals is I, the electric power at the terminlas is U * I. If the motor output at the shaft is P and P / (U*I) = 55%, is means the motor efficiency is 55%. Nothing to do with propulsion efficiency or propulsive efficiency. There are however motors much more efficient than that, well above 94% is possible at larger sizes.

[Stumble]

Originally Posted by Just Another Sa

That has nothing to do with propulsive efficiency.
55% propulsive efficiency means that for a kW at the shaft, thrust * boat speed = 550 W

If the voltage at the motor terminals is U, and the current in the wires at the terminals is I, the electric power at the terminlas is U * I. If the motor output at the shaft is P and P / (U*I) = 55%, is means the motor efficiency is 55%. Nothing to do with propulsion efficiency or propulsive efficiency. There are however motors much more efficient than that, well above 94% is possible at larger sizes.

Torquedo specs an input of 10kw and a propulsion force of 5.6kw. Ie 56% efficient. They do not specify how they come to that number, or the shaft power, so I am giving the maximum benefit of the doubt and assuming that 56% includes transmission losses, but not prop losses.

If they wanted to use standard outboard rating metrics this would be much easier on everyone, except their advertising department.