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Old 14-02-2020, 22:48   #91
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Re: Jimmy Cornell goes Electric, with a Cat

I think there is a lot of wishing for the Physics to be true in this thread. Sadly you just can't get around some issues.

Range - Most traditional boats can increase their range to a couple of hundred miles by very cheaply adding a couple of jerry cans and storing them in a locker. As I wrote before - to avoid sailing in a nasty strait in a gale or headwind I had to motor over 150 miles at about 7Kw per hour. It took about 24 hours of motoring to do this. It meant my wife would do the trip with me and we had a nice calm Bass Strait crossing.

The Physics is simple. We used 7Kw per hour - for 24 hours. That equals 168 Kw hours. (Our boat is really slippery too - it is more efficient than about 98% of cruisers out there).

The battery pack on a Tesla car is about 80Kwh. So you need TWO Tesla car batteries to do what we did. Then you have to re generate the power. It is not just a question of slightly increasing battery size - our boat has a battery capacity of 200 AH at 12 volts = 2.4Kwh. I would have to increase battery capacity by about 80 times what I have now, not just a little, 80 times is a huge amount. (Here in Australia, 20 KWh of Lithiums would cost me $16 000 and that will get me 3 hours of motoring at 7KW.. To match the fuel in my small tanks I need to get about 8 of these cabinet batteries - they will take up about all the room in the guest cabin and cost me about $130 000. Maybe I could get them for half price but I still have one cabin less and will be out of pocket $65 000) One of the pricey batteries will let me motor at 7 knots for 3 hours - that is 20 miles. I do that with about 8 litres of fuel.

If we put an extra 2 Kilowatts of solar on the boat (we could do this at a pinch being a cat) and say we get 8 good hours of charging every day, then we get 16Kwh of charge back in the batteries. So instead of anchoring at Eden and filling up in one hour it would have taken us about 10 days to charge the batteries up again. After a perfect crossing with perfect sun afterwards.

We could have a generator running as well. Maybe a 5Kw Panda at $12 000. that would need to run all the time I am motoring. So any dreams of quiet motoring are fading quickly.

My mates who had an electric pancake motor on their boat removed it. They had to run their generator and it was undersized at 5KVA. They often ran out of amps when cruising and had to run the generator for LONGER than they used to run their main engine - because it was undersized. So the amount of noisy engine time increased and they had much less fun cruising. Or you could get a generator with the same capacity as that needed for full surge powering for an extended time - that is a full size engine anyway.

I love electric cars and lust after them. They get to do lots of short journeys and their battery packs are massive. They connect to very fast chargers and some can be fully charged in less than half an hour. The situation on a cruising boat, well away from a marina is vastly different. For me the maths in no way stacks up. I don't motor much but want to be able to do 100 miles or so if needed. Twin outboards are cheaper, very reliable and fast under sail. Electric motors would cause a massive reduction in my cruising ability. A marina based daysail boat is a totally different kettle of fish and would be a good candidate for electric - but for long term cruising, the numbers don't work out for me.

cheers

Phil
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Old 14-02-2020, 23:37   #92
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by catsketcher View Post
I think there is a lot of wishing for the Physics to be true in this thread. Sadly you just can't get around some issues.

Range - Most traditional boats can increase their range to a couple of hundred miles by very cheaply adding a couple of jerry cans and storing them in a locker. As I wrote before - to avoid sailing in a nasty strait in a gale or headwind I had to motor over 150 miles at about 7Kw per hour. It took about 24 hours of motoring to do this. It meant my wife would do the trip with me and we had a nice calm Bass Strait crossing.

The Physics is simple. We used 7Kw per hour - for 24 hours. That equals 168 Kw hours. (Our boat is really slippery too - it is more efficient than about 98% of cruisers out there).
So, the Oceanvolt solution is to add a generator (exactly as you said further down in your post). In their double 15 kW saildrive example they have a 15 kW generator with 100l of diesel (and 17.5 kWh LiFePO4) to get 170 nm total range. Would this seem doable?

https://oceanvolt.com/twin-saildrive-15/

It does seem overly complicated to remove reliable diesel engines just to replace them with a load of other systems AND a diesel generator.

Maybe for performance type catamarans (and monohulls) there is a good point, though? If the extended range and diesel is reserved for emergencies/safety and the majority mode is to go by sail using hydrogeneration?

As sailors we're already used to the fact that going from A to B isn't the press of a button but something that takes a lot of planning and the ability to constantly adapt to a changing environment. Maybe going electric (with an added, properly sized diesel generator) wouldn't be that difficult after all?
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Old 15-02-2020, 01:22   #93
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Re: Jimmy Cornell goes Electric, with a Cat

The only zero carbon footprint boat you'll ever see is that one in the empty slip next to you.
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Old 15-02-2020, 01:38   #94
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Re: Jimmy Cornell goes Electric, with a Cat

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The only zero carbon footprint boat you'll ever see is that one in the empty slip next to you.
To be fair, I don't think they (Cornell or Outremer) are promising a zero carbon footprint boat. They're saying "all electric" and talking about a voyage with "no fossil fuels" aboard.

An LCA would obviously be interesting as well, but sailing around the world with a modern cruising cat and zero fossil fuels, that's cool in itself. (IMHO)
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Old 15-02-2020, 01:51   #95
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Re: Jimmy Cornell goes Electric, with a Cat

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Hi,


where did you get that information from?
Sounds very inefficient, as Europe has a lot of its own forests.

Apart from that Germany is strongly set towards renewables:
Here it is:
https://www.forestresearch.gov.uk/to...-wood-imports/
Quote:
The vast majority of UK imports of plywood and wood pellets came from countries outside the EU in 2017:

The USA (59%) and Canada (21%) provided the majority of wood pellet imports to the UK.
wood pellets are used for 'green' power generation.
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Old 15-02-2020, 02:24   #96
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Re: Jimmy Cornell goes Electric, with a Cat

Ha, now post Brexit, the EU had that issue solved by the Brits themselves ;-)
Improved climate record for free.
Rofl!
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Old 15-02-2020, 02:26   #97
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Re: Jimmy Cornell goes Electric, with a Cat

If I'd had the money, I would, but for now that's not an option, unfortunately.

The thread was for another project of mine, which involves improving the looks of dated boats with simple means.

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Actually, your cat is probably pretty low impact compared to most folk living in the EU.

Are you thinking of changing btw, given the Lagoon 38 query?

Pete
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Old 15-02-2020, 03:14   #98
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Re: Jimmy Cornell goes Electric, with a Cat

The electric boat is super-dumb. Diesel is a wonderful fuel and we should be thankful for it. I can motor across an ocean for days when becalmed. Electric can’t do that. The KWh of energy embedded in the diesel in my tanks cannot be replaced with any number of solar panels, not even a tiny, tiny percentage of it.

Diesel can also be made in a carbon neutral way. Synthesised. That is the future. It is be more expensive, maybe double the cost, but that still is cheap given the massive advantages of diesel.

Enjoy your diesel and leave the guilt and self flagellation to Greta and Jimmy. When the fossil variety gets banned there will be a replacement.
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Old 15-02-2020, 03:41   #99
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Re: Jimmy Cornell goes Electric, with a Cat

If you talk at the current situation it might not be feasible for many to go full electric, agreed. Especially those going to very remote locations might want an engine which can be run over extendet periods of time.
To call it "dumb" is not at all the proper wording in my eyes though.

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.

I do agree that there are moments when one needs to motor longer distances, but I do strongly hope that hydrogen based engines will eventually find their way into boating too. This technology will evolve faster one companies like "Nikola" https://nikolamotor.com/one have opened the door for mainstream usage.
It's new technology and it will take many years until its mainstream, but, I do favour it over another type of Diesel.

Apart from that, battery technology is evolving very very rapidly, so there is much more to come in the following years. Same applies to solar arrays. It's only a question of time when we will be able to harvest solar energy from photovoltaics on the sails.
For now its not possible, but that will change eventually.

The synthesized Diesel is good for a transition period, much better than traditional Diesel, but it can not be the longterm solution.

I do think its
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The electric boat is super-dumb. Diesel is a wonderful fuel and we should be thankful for it. I can motor across an ocean for days when becalmed. Electric can’t do that. The KWh of energy embedded in the diesel in my tanks cannot be replaced with any number of solar panels, not even a tiny, tiny percentage of it.

Diesel can also be made in a carbon neutral way. Synthesised. That is the future. It is be more expensive, maybe double the cost, but that still is cheap given the massive advantages of diesel.

Enjoy your diesel and leave the guilt and self flagellation to Greta and Jimmy. When the fossil variety gets banned there will be a replacement.
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Old 15-02-2020, 03:58   #100
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by Franziska View Post

I do agree that there are moments when one needs to motor longer distances, but I do strongly hope that hydrogen based engines will eventually find their way into boating too. This technology will evolve faster one companies like "Nikola" https://nikolamotor.com/one have opened the door for mainstream usage.

It's new technology and it will take many years until its mainstream, but, I do favour it over another type of Diesel.
Related to this, good news from Norway:

Quote:
World’s first liquid hydrogen fuel cell cruise ship planned for Norway’s fjords

Vessel to be retrofitted by 2023 will combine a 3.2MW hydrogen fuel cell with battery storage
https://www.rechargenews.com/transit...rds/2-1-749070
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Old 15-02-2020, 10:42   #101
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by catsketcher View Post
I think there is a lot of wishing for the Physics to be true in this thread. Sadly you just can't get around some issues.

Range - Most traditional boats can increase their range to a couple of hundred miles by very cheaply adding a couple of jerry cans and storing them in a locker. As I wrote before - to avoid sailing in a nasty strait in a gale or headwind I had to motor over 150 miles at about 7Kw per hour. It took about 24 hours of motoring to do this. It meant my wife would do the trip with me and we had a nice calm Bass Strait crossing.

The Physics is simple. We used 7Kw per hour - for 24 hours. That equals 168 Kw hours. (Our boat is really slippery too - it is more efficient than about 98% of cruisers out there).

The battery pack on a Tesla car is about 80Kwh. So you need TWO Tesla car batteries to do what we did. Then you have to re generate the power. It is not just a question of slightly increasing battery size - our boat has a battery capacity of 200 AH at 12 volts = 2.4Kwh. I would have to increase battery capacity by about 80 times what I have now, not just a little, 80 times is a huge amount. (Here in Australia, 20 KWh of Lithiums would cost me $16 000 and that will get me 3 hours of motoring at 7KW.. To match the fuel in my small tanks I need to get about 8 of these cabinet batteries - they will take up about all the room in the guest cabin and cost me about $130 000. Maybe I could get them for half price but I still have one cabin less and will be out of pocket $65 000) One of the pricey batteries will let me motor at 7 knots for 3 hours - that is 20 miles. I do that with about 8 litres of fuel.

If we put an extra 2 Kilowatts of solar on the boat (we could do this at a pinch being a cat) and say we get 8 good hours of charging every day, then we get 16Kwh of charge back in the batteries. So instead of anchoring at Eden and filling up in one hour it would have taken us about 10 days to charge the batteries up again. After a perfect crossing with perfect sun afterwards.

We could have a generator running as well. Maybe a 5Kw Panda at $12 000. that would need to run all the time I am motoring. So any dreams of quiet motoring are fading quickly.

My mates who had an electric pancake motor on their boat removed it. They had to run their generator and it was undersized at 5KVA. They often ran out of amps when cruising and had to run the generator for LONGER than they used to run their main engine - because it was undersized. So the amount of noisy engine time increased and they had much less fun cruising. Or you could get a generator with the same capacity as that needed for full surge powering for an extended time - that is a full size engine anyway.

I love electric cars and lust after them. They get to do lots of short journeys and their battery packs are massive. They connect to very fast chargers and some can be fully charged in less than half an hour. The situation on a cruising boat, well away from a marina is vastly different. For me the maths in no way stacks up. I don't motor much but want to be able to do 100 miles or so if needed. Twin outboards are cheaper, very reliable and fast under sail. Electric motors would cause a massive reduction in my cruising ability. A marina based daysail boat is a totally different kettle of fish and would be a good candidate for electric - but for long term cruising, the numbers don't work out for me.

cheers

Phil


This post goes right to the heart of the matter. The technology is not yet mature enough to be practicable in cruising boats.

I also long for the day when I can have one set of batteries for both house and propulsion with both a solar and a rapid recharge system which will fit into a shoe box. Don't think I'll see it in my lifetime though.
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Old 15-02-2020, 14:16   #102
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Re: Jimmy Cornell goes Electric, with a Cat

I now withdraw my overall assertion. Now I think electric engines might be an appropriate technology for 0.2% of cruisers rather than the majority of cruisers that I claimed before.

I was struck (down) mostly by the arguments from Catsketcher. His/her? arguments were supported by fairly straight forward physics/engineering. I should have done those calcs before I made my claim.

The clincher for me that changed my mind was the problem of reduced range under power. I cannot develop an electric engines proposal that is OK for me vis-a-vis range under power . It is not OK because any proposal I can develop does not meet my requirements. See immediately below.

I crossed the pond from Cape Verde to Antigua. I took 18 days in total. The winds were very light for the first 3 days. Then we got the trade winds and could turn the diesel motor off. I chose to motorsail continuously for those 3 days. The basic stats were one 40hp diesel motor set at 1800 rpm consuming 2 litres of diesel per hour. My memory is that the boat was doing about 5 knots, perhaps a little more. This would not have been possible if I had electric motors for propulsion. I have reworked the design lots of ways but the 'physics' analysis shows that it does not stack up to what I want. Other cruisers are obviously different from me. Below I describe some different cruiser types and whether I could recomment to them that they go for electric engines.

But what about the cruisers with engineless boats? Surely I could recommend to them that they could go with electric engines instead of nothing. This leads to who are the engineless sailors? I can think of Captain Cook. In the more 'modern' era I know of Lyn/Larry Pardy and Donald Street. But today there are not many cruisers with engineless boats. In 6 years of cruising I met one. It was a true cruiser on a 23 foot monohull. I towed his boat through the Panama Canal. This segment of cruisers is statistically insignificant.

But what about cruisers that are only day sailors? There are lots of boats that either never sail or when they do, only day sail. Could I recommend that they go electric? Again closer analysis blows this one out of the water. The boats at best might only day sail. But the owners mostly believe that one day (perhaps even real soon) they will do a 'longer cruise'. Having this cruising capability is important to their psyche. So there is a very small group left that I could make a recommendation to go electric propulsion - rich, only day sail now and do not ever want to do more than day sailing. Again statistically insignificant.

But what about the fervent green cruisers? I heard recently of some interesting fervent green cruisers on one boat. They had a goal of sailing around the world fossil fuel free. However they took 72 days to sail from South America to the Marquesas because they never used their engine. By comparison my passage from Panama to the Marquesas took 28 days but I used the engines a little bit. And I thought 28 days was long!

I have heard of a few more cruisers that are green but not to the same extent as the one above. So I could make a recommendation to go electric propulsion if the cruiser was tending to the level of being a fervent green and was rich. This is how I got my guess of 0.2%.

BTW I am talking about rich cruisers because I now think it is more expensive to go electric compared to green. Electric drive motors could easily be more expensive than the equivalent diesels, the saildrives might be more expensive, you have to have a genset and a water generator. You need more batteries and they probably need to be lithium.


Now that that debate is over for me, lets please talk about something non-contravertial - how about the topic should we carry guns on our boats?

Cheers

Brian
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Old 15-02-2020, 17:54   #103
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Re: Jimmy Cornell goes Electric, with a Cat

My understanding is that Jimmy is building the boat to take part in a rally. The circumstances prevailing during a rally are far different than those which often prevail for the cruiser where many voyages take place in remote areas without the company of other boats. Jimmy can afford to be without adequate power because he can call upon other participants or the rally organizers for assistance. However the design of the vessel from an available power for contingencies viewpoint is inadequate.

Jimmy is undoubtedly an exceptionally experienced seaman and has written a number of publications very valuable to cruisers and I have purchased some of them for reference purposes in the past and have a copy of his World Cruising Routes on my bookshelf at the moment. However if Jimmy is extolling the virtues of the all electric boat for the general cruiser I fear that he is seriously in error. For example, being able to achieve 5 knots in an ultra light boat in calm seas with 1.5 kW is not sufficient to keep you off the shear-to-the-sea, 140 or so nm long, N/S trending Zeytdorp Cliffs in a westerly gale and it should not be so implied or suggested by an individual of such authority in cruising matters.

Hopefully Jimmy is not joining that group of celebrities who sail across oceans on professionally crewed boats with a pack of cheer leaders hanging on the subtleties of every wind shift to induce the rest of us to forgo our sinful use of the dreaded hydrocarbons and is doing it as a challenge to himself.
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Old 15-02-2020, 22:18   #104
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Re: Jimmy Cornell goes Electric, with a Cat

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I was struck (down) mostly by the arguments from Catsketcher. His/her? arguments were supported by fairly straight forward physics/engineering.
You are certainly right with your considerations, however what is not said is that typically electric cruisng boats are actually having a generator on board and the people are very happy with this. And the discussed Outremer 45 would actually need a rather small generator and would for sure not be underpowerd. This can certainly be the different with fat, slow boats whith a bad hull resistance curve. An all electric boat is the more radical solution but if you look at the systems installed, very few have no generator. The genset is not used very often but just there when needed. The advantage of such a solution is that most of the time you can motor all electric without diesel (with elecric energy harvested before) and you have less maintenance (especially on a cat with 2 motors) .
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Old 16-02-2020, 01:04   #105
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Re: Jimmy Cornell goes Electric, with a Cat

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You are certainly right with your considerations, however what is not said is that typically electric cruisng boats are actually having a generator on board and the people are very happy with this. And the discussed Outremer 45 would actually need a rather small generator and would for sure not be underpowerd. This can certainly be the different with fat, slow boats whith a bad hull resistance curve. An all electric boat is the more radical solution but if you look at the systems installed, very few have no generator. The genset is not used very often but just there when needed. The advantage of such a solution is that most of the time you can motor all electric without diesel (with elecric energy harvested before) and you have less maintenance (especially on a cat with 2 motors) .
Yes exactly! No need to be very black and white about this.

And the more I read this discussion, the happier I am that Cornell and Outremer are doing this .

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.

The idea, after all, is to primarily make us of that other solar sourced renewable: wind.
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