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Old 08-04-2021, 04:02   #511
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by Sos View Post
It seems to me that Jimmy was lead by the advice from Oceanvolt who said the system would work. Outremer told him to fit a generator but he decided not too. I would of thought Oceanvolt would be doing everything possible to get it to work now since it is not a good endorsement of their products. If they didn't tell him it would work then they should have made that clear to everyone including us!
When I read the bog posts correctly, it did work, when they tested it with Outremer and OV personal on board in the med.
But when the left on their own it didn't.
Not sure why.
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Old 08-04-2021, 04:08   #512
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by harlem24 View Post
When I read the bog posts correctly, it did work, when they tested it with Outremer and OV personal on board in the med.
But when the left on their own it didn't.
Not sure why.

The difference between expectations and reality!
At least he tried
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Old 08-04-2021, 05:20   #513
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by harlem24 View Post
When I read the bog posts correctly, it did work, when they tested it with Outremer and OV personal on board in the med.
But when the left on their own it didn't.
Not sure why.

https://youtu.be/6EplXM0fksw
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Old 08-04-2021, 05:23   #514
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by Sos View Post
It seems to me that Jimmy was lead by the advice from Oceanvolt who said the system would work. Outremer told him to fit a generator but he decided not too. I would of thought Oceanvolt would be doing everything possible to get it to work now since it is not a good endorsement of their products. If they didn't tell him it would work then they should have made that clear to everyone including us!
Not sure about that, apparently both Outremer and the Oceanvolt people advised him to install a generator - as by the way is standard in their larger system:
https://oceanvolt.com/twin-saildrive-15/
2 x 15kW sail drive motor
17,5kWh Lithium battery bank
15kW DC Generator
2kW Charger
Hydrogeneration feature

He seems to have made a couple of poor judgments and ignored the advice he received. He installed so little solar, and so many power-hungry systems that the boat didn't even work without using the electric motors.
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Old 08-04-2021, 05:46   #515
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by harlem24 View Post
When I read the bog posts correctly, it did work, when they tested it with Outremer and OV personal on board in the med.
But when the left on their own it didn't.
Not sure why.
It worked in testing in 'near-perfect conditions' - eg decent wind, and flat seas . . .
It did not work in the actual sort of conditions you almost always get on passage - days of very light wind (so quite low boat speed) and days of mixed/unsettled seas (so less smooth flow over the re-gen props). Hydro re-gen is just too vulnerable to actual sailing conditions and also to junk (weeds and nets and more solid stuff) in the water to be totally solely dependant on it.

There have now been enough of these sorts of experiments to allow us to draw pretty firm conclusions. You can make it work - if and only if - #1 you are only planning to use the electric drive for only harbour entry and exit, you will not be able to count on it for making many miles on passage, so you really need to plan to and be able to sail 'engineless' (which is certainly possible but takes a certain mindset), #2 you need to absolutely totally minimize consumption and NOT have all the electric mod-conveniences (and not many big screens and computers all on while on passage) and electronics, and if you want the electric kitchen then also design in an 'alternative functional on-passage kitchen without big electrical draw (copy RTW race boat design); #3 have a ton of solar - in the real world it is by far the best base load charging source and is perfect on a multihull with all the surface area; and #4 an excellent sailing boat which is the one thing (and pretty much only) Jimmy did get right.

It would be interesting to see a more practical and 'minimalist (and probably need be younger) sort of experienced engineless sailor give this a go.
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Old 08-04-2021, 06:41   #516
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by olaf hart View Post
I found some time to watch the video now. Very interesting!

But how frustrating that the biggest (right?) problem was the servoprop constantly recalibrating! It sounds like something that possibly could be fixed with a simple firmware upgrade.

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Old 08-04-2021, 07:03   #517
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Re: Jimmy Cornell goes Electric, with a Cat

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yeah cos theres no emissions expelled in building the boat is there???

sorry but this is just yet more hypocritical virtue signalling

the least emissions path by far would be to NOT BUILD ANOTHER NEW BOAT and make do with an existing one.
Spot on...... We can all do our part, but this is "redonkulous"
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Old 08-04-2021, 14:16   #518
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Re: Jimmy Cornell goes Electric, with a Cat

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It strikes me that this was a commercial rather than a truly eco exercise.


The Parleys have already extracted the very small commercial benefit from zero emissions, way before it became trendy. Others like Sean above have also circumnavigated without an engine with zero emissions with no commercial benefit at all.


No disrespect intended toward Mr Cornell, I have many of his books and he has achieved much, but there is very little commercial benefit in sailing a normal catamaran around the world without an engine, see RTW racing records. A zero emission high tech boat with a generator is no different from the majority of long term cruisers.


I admire people that experiment, I have seen a cruiser dump $110,000 of batteries after a maiden voyage because his charging system failed. I have seen a diesel / electric boat with electric only cooking tied to the dock for more than a year because of technical issues. These are unsung heroes.
But were the Pardeys etc truly zero emission?

Didn't they use fuel for cooking, heating etc? Weren't they frequently towed into harbours, marinas etc?

I'm not having a dig, bit I think Cornell attempted to go zero emission, none from cooking, none from getting into anchorages, marinas, anywhere.
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Old 09-04-2021, 14:32   #519
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Re: Jimmy Cornell goes Electric, with a Cat

I watched the Oceanvolt debrief linked above, and between about 19:40 and 20:30 or so, it seems like Connor said that in their most range-conservative mode, only one motor drawing 1kw, they got ~4 knots, and hammer down they drew 8kw. Then he said with both motors going fullout they only got 6.5 knots.

Wow! Did I miss something? That would mean 8 kw x 2 motors = 16 kw draw, to only increase from 4 knots to 6.5. That's all you get increasing the draw from 1 to 16 kw? It seems like maybe they mis-spoke? 16 times the power draw to not even double the speed?
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Old 09-04-2021, 15:06   #520
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Re: Jimmy Cornell goes Electric, with a Cat

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I'm surprised he didn't just install a say 5kw generator and go again. Obviously with the intention of using the generator as little as possible.

IMO that would have been more instructive. To see just how little fossil fuel is needed, rather than just saying "it doesn't work.".
Exactly this. Less flashy but a far more interesting experiment. Then use that to revise the plan and try to cut diesel consumption further.

1300W solar is just insufficient for the task as well. 1300W is great for a well equipped cat with an electric galley and diesel for motive power. 1800W or even 2000W would have help, as would have a backup diesel genset.
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Old 09-04-2021, 15:09   #521
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Re: Jimmy Cornell goes Electric, with a Cat

They had 2 x 15kW motors. Therefore At WOT the consumption would have been just over 30kWh. His propulsion bank was about 58 kW.
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Old 09-04-2021, 15:10   #522
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by Bullshooter View Post
I watched the Oceanvolt debrief linked above, and between about 19:40 and 20:30 or so, it seems like Connor said that in their most range-conservative mode, only one motor drawing 1kw, they got ~4 knots, and hammer down they drew 8kw. Then he said with both motors going fullout they only got 6.5 knots.

Wow! Did I miss something? That would mean 8 kw x 2 motors = 16 kw draw, to only increase from 4 knots to 6.5. That's all you get increasing the draw from 1 to 16 kw? It seems like maybe they mis-spoke? 16 times the power draw to not even double the speed?
Yes something is not right in those numbers.

Power to overcome drag increases by the cube of velocity.

So (6.5/4)^3 = ~4.5x not 16x. So my guess is either the 4 knots or the 1 kw was "optimistic rounding". As in doing 3.6 knots and calling it "about 4" and pulling 1400 watts and calling it "about 1 KW". Some people might call that lying. Still even that comes up short.

Or that 4 knots was with one hell of a favorable current but OV should know that is an outlier so some might call that lying too.

Whatever it was the datapoints don't work out.
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Old 09-04-2021, 15:16   #523
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Re: Jimmy Cornell goes Electric, with a Cat

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It worked in testing in 'near-perfect conditions' - eg decent wind, and flat seas . . .
It did not work in the actual sort of conditions you almost always get on passage - days of very light wind (so quite low boat speed) and days of mixed/unsettled seas (so less smooth flow over the re-gen props). Hydro re-gen is just too vulnerable to actual sailing conditions and also to junk (weeds and nets and more solid stuff) in the water to be totally solely dependant on it.

There have now been enough of these sorts of experiments to allow us to draw pretty firm conclusions. You can make it work - if and only if - #1 you are only planning to use the electric drive for only harbour entry and exit, you will not be able to count on it for making many miles on passage, so you really need to plan to and be able to sail 'engineless' (which is certainly possible but takes a certain mindset), #2 you need to absolutely totally minimize consumption and NOT have all the electric mod-conveniences (and not many big screens and computers all on while on passage) and electronics, and if you want the electric kitchen then also design in an 'alternative functional on-passage kitchen without big electrical draw (copy RTW race boat design); #3 have a ton of solar - in the real world it is by far the best base load charging source and is perfect on a multihull with all the surface area; and #4 an excellent sailing boat which is the one thing (and pretty much only) Jimmy did get right.

It would be interesting to see a more practical and 'minimalist (and probably need be younger) sort of experienced engineless sailor give this a go.
and throw in an emergency genset for good measure. The solar is a big one. Nothing beats solar in terms of consistent, no nonsense, generation. Someone who makes this work is a going to have a lot of solar and a genset and willingness to use the motor more sparingly and sail in light wind.

I don't think induction is necessarily bad it sure beats having to source propane everywhere but the system/plan has to accomodate it.
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Old 09-04-2021, 15:21   #524
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by Simon.Sails View Post
Not sure about that, apparently both Outremer and the Oceanvolt people advised him to install a generator - as by the way is standard in their larger system:
https://oceanvolt.com/twin-saildrive-15/
2 x 15kW sail drive motor
17,5kWh Lithium battery bank
15kW DC Generator
2kW Charger
Hydrogeneration feature

He seems to have made a couple of poor judgments and ignored the advice he received. He installed so little solar, and so many power-hungry systems that the boat didn't even work without using the electric motors.
IIRC he said he has never sailed with a genset. Just using the alternator on his primary diesel. I wonder after a lifetime of sailing and mostly using the diesel to move the boat even if it is also charging the batteries led to a case where he vastly underestimated just how much electrical energy was being supplied day to day by the diesel on his previous boats.
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Old 09-04-2021, 15:24   #525
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by Sos View Post
It seems to me that Jimmy was lead by the advice from Oceanvolt who said the system would work. Outremer told him to fit a generator but he decided not too. I would of thought Oceanvolt would be doing everything possible to get it to work now since it is not a good endorsement of their products. If they didn't tell him it would work then they should have made that clear to everyone including us!
Oceanvolt usually shows a DC genset in their large system designs. Pretty sure the "no genset not even one for emergencies" was 100% Jimmy and coming from nobody else in the industry. Even if OV was sure their system would perform adequately in 99% of cases the genset provides a safety net that avoids very embarrassing headlines like this.
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