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Old 16-02-2020, 02:11   #106
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by poiu View Post
The electric boat is super-dumb. [...]

What a statement! Don't need to read any further, no credit given, sorry.
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Old 16-02-2020, 02:14   #107
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by Franziska View Post
[...]

An engine can be a safety feature when trying to escape bad wether.If you are becalmed, sufficiently equipped with time, water and food, I think the better option is to wait for wind.


[...]

Exactly! Like we've done for centuries (and most of the sailor survived it). Today, our time seems much more precious, even though we have more of it (in terms of life expectancy).

Strange, isn't it?
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Old 16-02-2020, 03:42   #108
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Re: Jimmy Cornell goes Electric, with a Cat

One has to remember that most people are on a schedule.
Most have limited time to spend travelling.
So in many cases they want to go somewhere and to get there they motor.
My only question then is, why do the own/rent sailboats if they motor most of the time?
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Old 16-02-2020, 04:04   #109
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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.
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Well said.
Where did the OP or anyone talk about emissions. The OPs post said Zero Fossil fuels. Which is true, the boat will not be run with any fossil fuels. Can;t see hot that is difficult to comprehend.

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Neither Carbon fiber nor its manufacturing is the slightest bit green. Nor is it recyclable in any meaningful way, it is in fact a big chunk of plastic that will never ever decompose, just like a fiberglass boat. Virtually nothing about the boat is any greener than any other sailboat with a solar array, when under sail. That said, glad he is able to parlay his reputation for a bunch of free or heavily discounted equipment, to include the boat. Good on him. As an experimental propulsion sailboat it may in the future lead to the replacement of the auxiliary Diesel engine, and that okay if it actually has any real range.

Wood! It’s the original carbon fiber...

Fair winds,
Well the boat is made in France, so will have used Nuclear power. If it was made in Germany it would all the power used to build it at the yard would have been from coal and gas. So that is certainly greener.

One thing to think about for those that love combustion engines, is that as more boaters retro convert to electric propulsion, there should be some good bargains on diesel engine.
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Old 16-02-2020, 05:17   #110
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Re: Jimmy Cornell goes Electric, with a Cat

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.......
Regarding the saildrive leg; I've eliminated mine and designed/built custom retractable legs which cost me ~$2500 in welded 316 Stainless, the POD drives are wonderful options here as they eliminate all gearing which even the Oceanvolts have, so regen should be more effective/efficient.
......
I would love to see some pictures or drawings of your drive legs.
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Old 16-02-2020, 07:37   #111
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Re: Jimmy Cornell goes Electric, with a Cat

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As you imply, performance catamarans seem better suited for this. For Cornell's voyage they're talking about a hybrid Outremer 4X/45, so I bet the boat will be light and fast.
Another point to consider regarding specific advantages of a cat for going electric is, that having two motors, you can also use the two motors for hydrogeneration. Hence there is the double potential for harvesting energy when sailing.

With this, an Outremer 45 can, after sailing 6 hours with 10 knots, motor along with 6 kts for about 2 hours, using the energy harvested with hydrogeneration. This is calculated with fixed props. Using the adjustable pitch solution from Oceanvolt you can expect at least factor 2 more energy from the hydrogeneration.
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Old 16-02-2020, 11:04   #112
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Re: Jimmy Cornell goes Electric, with a Cat

Stop press to all of you who were ready to move on to the next topic about guns

This page has some cool (and unverified) calculations suggesting going electric is viable, even for people crossing oceans and wanting to get where they are going.

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Old 16-02-2020, 12:10   #113
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Re: Jimmy Cornell goes Electric, with a Cat

I think one of the issues with this topic is that the electric motor sellers will be loud with the successful installations and no one will publish the tales where the motors were switched back out for diesel. Its called reporting bias.

One other thing is the regen rating for the Outremer. A performance cat gets its high performance by being low drag - drag is reduced by reduction in weight and hull beam. Even a small amount of drag such as growth produces a large decrease in speed on such a cat.

So I expect that using regen will have a highly significant effect on the boat. Once or twice people have put three bladed props on cats that could sail nicely and the effects have been to reduce performance markedly.

What we really need are resistance curves for the Outremer. Then we can look at the power suggested for regen and see the effect it would have on boatspeed. I can't find any curves but if anyone could they would tell us lots.

Plus - I read the link above and it does do a little creative accounting, reducing speed is one (and required power). What is doesn't seem to do is include electrical losses. There will be significant losses in the power controller, batteries and high current cables that seem to get forgotten about. I am not sure how efficient the regen is and would be intrigued to find out the efficiency of the new electrical setups. We all know that internal combustion engines only get to about 35% efficiency on our boats. I would think the electrical set up would be more than double but am not sure of the exact numbers.
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Old 16-02-2020, 12:25   #114
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Re: Jimmy Cornell goes Electric, with a Cat

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One other thing is the regen rating for the Outremer. A performance cat gets its high performance by being low drag - drag is reduced by reduction in weight and hull beam. Even a small amount of drag such as growth produces a large decrease in speed on such a cat.
Sure, this might be the case.
However a Jimmy Cornell is probably not looking for high speed. For him, I guess, the "Performance"-Aspect is mostly interesting with respect to low drag at low speed - for super-efficient motoring and may be sailing with little wind only.
Please keep in mind that as soon as you are about to be overpowered, there is plenty of excessive energy available which you can convert into electric power - if you like.

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What we really need are resistance curves for the Outremer. Then we can look at the power suggested for regen and see the effect it would have on boatspeed. I can't find any curves but if anyone could they would tell us lots.
No, this does not really help. See above. Typically, as a cruiser, you don't aim to go with the maximum speed possible. 9-10 kts are fine and a knot less is typically no problem. If 12 kts were possible, you may decide to better generate electric power and move along more comfortably at the same time.
The Numbers: The Outremer 45 needs about a bit less than 100 kW engine power for 12 knots and a bit more than half of this for 10 knots.
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Old 16-02-2020, 14:07   #115
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by catsketcher View Post
I think one of the issues with this topic is that the electric motor sellers will be loud with the successful installations and no one will publish the tales where the motors were switched back out for diesel. Its called reporting bias.

Survivorship bias?


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Old 17-02-2020, 00:22   #116
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Re: Jimmy Cornell goes Electric, with a Cat

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Well the boat is made in France, so will have used Nuclear power. If it was made in Germany it would all the power used to build it at the yard would have been from coal and gas. So that is certainly greener.
When looking at the stats you will find, that almost 50% of the electric energy produced in Germany last year was renewables.
And in what universe is nuclear greener? Looking at the energy spent to built those plants and the repercusions when dealing with the waste, I am not sure...
Yes, if looking at CO2 it appears like they are better...
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Old 17-02-2020, 00:28   #117
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Re: Jimmy Cornell goes Electric, with a Cat

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What is doesn't seem to do is include electrical losses. There will be significant losses in the power controller, batteries and high current cables that seem to get forgotten about. I am not sure how efficient the regen is and would be intrigued to find out the efficiency of the new electrical setups. We all know that internal combustion engines only get to about 35% efficiency on our boats. I would think the electrical set up would be more than double but am not sure of the exact numbers.
Oceanvolt states that you loose about a knot of speed when using regen with servoprops. On a fast boat I likely wouldn't care.

If looking at a car you'll get about 70% of the energy back through regen.
Oceanvolt states that they'll achive 1kW of regen power per motor.
And the losses are not soo high, usually you are about 90-95% when charging a LiOn/LiFePo.
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Old 17-02-2020, 02:45   #118
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Re: Jimmy Cornell goes Electric, with a Cat

I don't want to come across as a Luddite but we do need to be very careful when a company tries to sell us stuff. We don't take all the claims of our toothpaste, cosmetics or fast food companies as gospel and I would be careful here.

There seems to be a bit of a shell game here. When talking about motoring, the Outremer and other people talk of needing very little power. I am very dubious about these claims because most people do not motor in totally calm conditions and the power required is almost certainly minimized by the regen companies. Then when they talk of regen, the boat is speeding along, doing maybe 12 knots.

Have many of our readers have done 12 knots - average - for a reasonable time, say four hours, in a cruising boat? I have, a few times and man it was amazing, but it is not common. 8 knots as an average is pretty common, we get some 9 knot days and we have had two days when we did 10 knots for 16 hours each (160 miles on the chart) - I smile remembering those days. But 12 knots as common, under autopilot, with the family happy and no one getting scared? Those conditions are really, really hard to find, they happen, but they are rare. (One time we never went below 14 knots for 45 minutes - that was great but very very uncommon).

So beware of the exponential thing the wind generator salesmen played with. "This generator puts out 400 watts" they would say - only for you to find out that you need to be in 28 knots - all day - to get that. Back where we anchor and the wind drops to 12-15 the power output plummets. Its an exponential thing - the kinetic energy of any fluid - wind or water - goes up by the square. So going at 7 knots you produce 49 units of energy, 8 knots 64 units and 12 knots 144 units. So you can see why Electrovolt give you the 12 knot reading. There is double the energy of the more achievable 8 knots.

Then they reverse the shell game to say - and you can now motor for hours, because they use the squared relationship to allow the low power output to give some longer times under power by going slow. Faster than reasonably achievable speeds under sail and lower than wanted speeds under motor. You shouldn't be able to have it both ways.

I will be very happy to see someone who is not company based, put all the figures together after a year of sailing with such a set up. I am dubious about the claims because it does not gel with the reality of my sailing. (Average speed under sail after a few thousand miles coastal - 7.5-8. Average motor speed 7) But data is king and I will always change my mind when shown data that shows me wrong. Until then I will sit stay with internal combustion, on the boat at least.

cheers

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Old 17-02-2020, 04:50   #119
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Re: Jimmy Cornell goes Electric, with a Cat

I have to say that I am struggling to understand all the negativity about electric boats. They have inherent compromises, we get that. Is it guilt that you haven't gone to something more earth friendly? I firmly believe that we go with what is good for us and I would never criticise your choices.
An example would be that in every one of these threads someone (or many) use the example of a long voyage under power and how they can go much farther with their tank of diesel. That fact is indisputable. What could be highlighted would be that with solar and patience, one will never be without fuel.
Rant over, Dan
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Old 17-02-2020, 07:19   #120
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Re: Jimmy Cornell goes Electric, with a Cat

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No one will buy a ZERO FOSSIL FUELS yacht if they are smart. Like the Silent 55, any practical electric yacht will need to be equipped with a backup propulsion system in order to sell to the knowledgeable mariner. They will need to have a diesel, LPG or LNG backup generators to charge batteries at night or in bad weather, as well as to take over directly powering the main electric motors in a pinch.
The hard thing about history is it evolves in real time. Nobody will buy an electric car either- just ask Mr. Musk! The fact we are discussing this topic is a sure harbinger that, while it may be decades away, as the technologies improve, Boats will follow the trend we’re seeing now with land-based transportation. Better batteries, efficiency gains in Solar & Wind recharge capabilities, and a desire for the Wealthy to one up each other will lead to a mainstream TeslaCat- might not be in my lifetime, but, as with any Paradigm disruption, the pebble has been tossed & the ripples are moving outward towards the inevitability of an electric future.
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