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Old 07-12-2020, 21:14   #256
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Re: Jimmy Cornell goes Electric, with a Cat

It looks like Cornell was sloppy in his calculations.

Also going all in on regen looks like a stunt.

Regen and solar would not have been a stunt.

As SeanD pointed out propulsion props are inefficient for regen. Better would have been a stand alone water gen system with optimised props and folders or feathering props on the sail drive.

Itís not that OVís product is bad, I donít see that but it didnít fit this use case.
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Old 07-12-2020, 22:47   #257
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Re: Jimmy Cornell goes Electric, with a Cat

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It looks like Cornell was sloppy in his calculations.

Also going all in on regen looks like a stunt.

Regen and solar would not have been a stunt.

As SeanD pointed out propulsion props are inefficient for regen. Better would have been a stand alone water gen system with optimised props and folders or feathering props on the sail drive.

Itís not that OVís product is bad, I donít see that but it didnít fit this use case.
I think you're jumping to conclusions re the cause of this result. There are several possibilities here between the OV regen doesn't work as expected on the one hand through to Cornell didn't do his energy budget properly on the other hand.

Maybe there is an electrical design fault. Maybe the regen wasn't activated properly. Maybe there was a charge control imbalance because there is one SD15 and one Servoprop. Maybe this, maybe that? It's a new boat with new technology for the crew, so who knows?

The report from Cornell raises questions re the data, in my mind. If he has one SD15 and one Servoprop, why does he expect only 800 watts at 8 knots, for starters when that is only what the SD15 would output? The output from the Servoprop is about three times that of the SD15.

A technical investigation will take place I'm sure, and then we'll see whats what. I'm reserving judgement until then.
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Old 08-12-2020, 03:59   #258
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Re: Jimmy Cornell goes Electric, with a Cat

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Itís not that OVís product is bad, I donít see that but it didnít fit this use case.
You may be right. The unfortunate marketing disaster for OV is that they have to convince prospective buyers (at least the ones that learn of this) that OV didn't do a good job outfitting Jimmy's boat, but that, "trust me," they will do a flawless job on MY boat. For a significant share of those that hear of this, even if they were on the fence, OV won't get a chance to "correct" the story -- these customers won't make the first call.


The real challenge here is that an all electric boat MIGHT be a viable option, if you can do it the way Jimmy envisioned it. You save all the weight, expense, maintenance, noise, fuel, bad Karma, etc of a diesel engine, with a small compromise. But, in a "Mostly" all electric boat, you have a generator, fuel tanks, etc, etc, etc. And as Jimmy points out, it isn't a "for emergency" thing -- it moves slowly but inexorably to a "normal SOP" thing. It's easy to drink cold coffee when you don't have the power to heat it -- it's harder to drink cold coffee when you just have to fire up the Genny!


I do agree with the concerns about the math. On my 43' boat with two people, when underway at 7 kts or more, with propane cooking (so, bottom line, NOTHING like Jimmy's scenario), my Watt and Sea coupled with 900W of solar, puts out about 20A at 12V, and my sails (daytime only -- I'm a local cruiser) are about energy neutral. Somehow, I can't see how he can loose so much power. And before anyone tears apart my energy balance, no, I don't actually use 20A continuous -- under way, it's closer to 10A. So, I'm a little above energy neutral -- but then, speed slows a bit, or the sun goes behind a cloud, or we microwave a drink....and there you go! LOL
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Old 08-12-2020, 05:08   #259
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Re: Jimmy Cornell goes Electric, with a Cat

why didn't they have wind generators?, I have one onboard tandem with solar and regenerate most or all of my electrical consumption, only on windless cloudy days do I need the genset
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Old 08-12-2020, 05:12   #260
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Re: Jimmy Cornell goes Electric, with a Cat

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why didn't they have wind generators?, I have one onboard tandem with solar and regenerate most or all of my electrical consumption, only on windless cloudy days do I need the genset

What is your practical daily output from your wind generator, in kWh? I had one of the highly rated Rutland 914 ones, and I got maybe 240 watt hours out of it, on a good day.



Did you notice the vast quantity of their consumption? The output of a wind generator would be a rounding error put up against that consumption.
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Old 08-12-2020, 05:16   #261
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by sailingharry View Post
You may be right. The unfortunate marketing disaster for OV is that they have to convince prospective buyers (at least the ones that learn of this) that OV didn't do a good job outfitting Jimmy's boat, but that, "trust me," they will do a flawless job on MY boat. For a significant share of those that hear of this, even if they were on the fence, OV won't get a chance to "correct" the story -- these customers won't make the first call.. . .

You're absolutely right. I have to think that OV must have started believing their own bullshirt. Otherwise they would have been extremely careful to make sure that Jimmy's power budget was going to be realistically covered by the realistic output of their systems -- and they would have checked it 10 times before turning Jimmy loose. In order to avoid this very situation.


As it is, the gap between real output and real consumption seems to have been huge. How could they have missed that? This is one of those PR disasters, which should be a PR disaster.
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Old 08-12-2020, 06:06   #262
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Re: Jimmy Cornell goes Electric, with a Cat

Don't think OV is affected at all. Someone who has the budget to do OV most probably has an intrinsic motivation, it may have failed now but someone will succeed. It's just the right thing to try (imho).

Imagine a Tyrannosaurus Rex who wants to become vegan and then - oh wonder - is weak. Vegan might be a good idea, but the T.Rex needs to adapt. Become smaller, smarter, nimbler and some things are just no longer possible. I guess it has to do with the customer: maybe a bit of a rush to do it soon and not enough time to really calculate things through and optimize all (most) elements. Not enough relevant knowhow (it's certainly not easy). A reluctance to forgoe some amenities?

From a cursorily glance at the blog it looks that energy production could have been more diverse (much more solar, wind). And primarily that the consumption side was much too high. Autopilot, high end electronics, two fridges. E.g. why not a windpilot to stop the constant drain from the autopilot? I just cannot believe that when they lived spartan they didn't produce lots of superfluous energy. But I'm no expert.
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Old 08-12-2020, 06:07   #263
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Re: Jimmy Cornell goes Electric, with a Cat

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What is your practical daily output from your wind generator, in kWh? I had one of the highly rated Rutland 914 ones, and I got maybe 240 watt hours out of it, on a good day.
My alternative power is 900W of Solar (which is performing dismally), my Watt and Sea (two thumbs up), and my D400 Wind Gen. My gut tells me that the D400 power output doesn't justify the shading it does to the solar panels. But I live on the windless Chesapeake Bay, and anchor in highly protected coves, so it may not be a fair assessment.


I've just added individual ammeters on all three, so I can monitor actual production. We are doing a 7-month extended cruise next summer, COVID permitting, and it will be entertaining to watch those readouts.


I'm using these. I'm sure they aren't quality, calibrated meters -- but I'm happy with the ballpark data they are giving me.
https://www.amazon.com/bayite-Digita.../dp/B01DDQM6Z4 Sadly, the price is up 50% since I bought mine 6 months ago.....
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Old 08-12-2020, 06:28   #264
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Re: Jimmy Cornell goes Electric, with a Cat

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Don't think OV is affected at all. Someone who has the budget to do OV most probably has an intrinsic motivation, it may have failed now but someone will succeed. It's just the right thing to try (imho).

Imagine a Tyrannosaurus Rex who wants to become vegan and then - oh wonder - is weak. Vegan might be a good idea, but the T.Rex needs to adapt. Become smaller, smarter, nimbler and some things are just no longer possible. I guess it has to do with the customer: maybe a bit of a rush to do it soon and not enough time to really calculate things through and optimize all (most) elements. Not enough relevant knowhow (it's certainly not easy). A reluctance to forgoe some amenities?

From a cursorily glance at the blog it looks that energy production could have been more diverse (much more solar, wind). And primarily that the consumption side was much too high. Autopilot, high end electronics, two fridges. E.g. why not a windpilot to stop the constant drain from the autopilot? I just cannot believe that when they lived spartan they didn't produce lots of superfluous energy. But I'm no expert.
He had 1300w which is pretty decent. Wind vanes are not that common on a cat for practical purposes.



I think we all know it can be done but I think this was an attempt at making it seem like it could be done in relative comfort. As a way to promote it for commercial use.

I just re watched uma. They didnt get the OV until they got to europe so they did the crossing with just solar.
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Old 08-12-2020, 09:57   #265
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Re: Jimmy Cornell goes Electric, with a Cat

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He had 1300w which is pretty decent. Wind vanes are not that common on a cat for practical purposes.
That's really quite decent - but with his consumption I think he would need more (and on a cat this would be possible, wouldn't it?). - Yes, never saw a windvane on a cat. It is only an example to take one element (stearing) and make it more energy efficient than now.

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I think we all know it can be done but I think this was an attempt at making it seem like it could be done in relative comfort. As a way to promote it for commercial use.
Maybe that's the point: commercial use. (And almost no change to a "normal" boat).

If I look at https://cornellsailing.com/aventura/...cial-features/ except for OV it's quite boring (standard). E.g.: don't think Brookes & Gatehouse is optimized to save energy. I'm conviced that you can achieve his goals, a.o. relative comfort, but it needs more work, you have to optimize in detail.

Btw. looking at the above mentioned link, Cornell is (was) quite the extremist : "if we really care about the future of the planet there is only one answer: we must go 100% green!". Personally I'd rather go with https://en.wikipedia.org/wiki/2000-watt_society and don't have a problem to burn some diesel accordingly... (but zero carbon emissions sounds/is better, I fully admit).
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Old 08-12-2020, 10:48   #266
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Re: Jimmy Cornell goes Electric, with a Cat

Another way to look at the amount of Solar on Cornell's boat is to compare it to another known (working) example.

I always tend to mention CatNewBee's boat because he's a member here and has a very good thread detailing his setup in actual real cruising use: https://www.cruisersforum.com/forums...ey-201795.html

As I mentioned on the previous page CatNewBee seems to be able to go several days as a minimum with an all electric consumption boat (galley, washing machine, water maker, etc, plus all the other normal items) and all WITHOUT regen.

But, I think CNB mostly cruises as a couple (Cornell had what, 5 onboard?)

AND, I think CNB has 1650W of Solar (and 1000Ah at 12V).

So just at a glance Cornell's 1300W seems to indicate a deficit there already.

Ok I understand that the idea was to make A LOT of charging power from the from the OV regen system, but that doesn't work at anchor when the boat isn't moving.

Given that sitting at anchor somewhere occupies a large amount of a cruising boat's time, I don't see a very good plan for this?

Overall the Cornell project seems very poorily planned.

Worse still given that it was meant to be a 'Showcase' example of what can be achieved.

Such a pity.



PS CNB, please jump in and correct me if I have misquoted any of your boat's details
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Old 08-12-2020, 16:54   #267
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Re: Jimmy Cornell goes Electric, with a Cat

You can see there isnít much room left on the outremer for solar unless you are putting soft panels under the boom. 1300w seems to be a decent amount for a cat this size without going under the boom or other less efficient areas.

On a TS42 there is almost no room for solar. Depends on the cat.

The solid panels on davits is probably doing most of the work. Lots if shading issues on the roof when sailing. Maximizing your panels there probably is not too efficient.
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Old 08-12-2020, 18:10   #268
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Re: Jimmy Cornell goes Electric, with a Cat

Certainly how and where you will mount a large solar array needs to be considered if it's part of the plan for any new boat.

You see monohulls struggling with this, having them hanging way off the transom, and also folding up from the side stanchions for use at anchor.

It's definitely better if it can be pre-planned, and not just added as an fter thought.

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Old 09-12-2020, 09:51   #269
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Re: Jimmy Cornell goes Electric, with a Cat

Hm, not sure how much power the Panels have, but if you look at the installation the o'Kellys did on their Leopard there might be ways to mount more panels on the Outremer.
I'd guess that they mounted durable panels instead of high power ones.
So if we see four flexible panels that might be rated at 100Wp and four panels on the davids that would be rated at 225Wp. So there we have rated 1300Wp.
In good condition one will get 80% from the ridgit panels and 60% from the flexible ones.
That leaves you with 240W from the ones on the roof and 720W from the ridgit ones. So you are below 1kW of optimal output. If it's cloudy you'll get even less. Not enough to run a small house load, let alone a full electric galley for 5 plus all electronics.
I would suspect, that one needs at least 2kWp if not more for these kinds of loads.
And additional to that would come the regen.
Also the expectation to go on a circumnavigation with an unproven new boat is interessting.
And for sure there is self steering possible on a cat, several examples to be found on the interwebs, just have a lool
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Old 09-12-2020, 09:51   #270
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Re: Jimmy Cornell goes Electric, with a Cat

I wonder if more smaller panels would get you past the shading issues?
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