Jimmy Cornell goes Electric, with a Cat

[jbinbi]

Originally Posted by JustMurph

I was going to respond to seandepagnier, but it's really not worth it.

Right? Clearly he knows the best way to live and sail and what is best for everyone.

It would be interesting to know how much diesel is used by the ENTIRE pleasure boating sailing community. And then compare it to how much is used by the ENTIRE pleasure boating motor boating community. And then compare that to what is used by the shipping industry, the military, etc.

A quick google search shows that a cruise ship burns 50-100,000 gallons a day. 0.5M gall per week of cruising. There are about 400 cruise ships active in the world. 200M gallons of fuel per week (in non covid times). This is just pleasure cruising. What do the Navies of the world use (non nuc powered boats) on top of this? What about Cargo ships, etc.

And you are worried about whether or not your extra 5 gallons used rather than waiting for your weather window or sailing upwind in 30kts will make a difference?

[Adelie]

Originally Posted by JustMurph

I was going to respond to seandepagnier, but it's really not worth it.

Then why mention it in the first place?

[Narfi]

Originally Posted by Adelie

Then why mention it in the first place?

A good philosophical question.... (I am no philosopher... but sometimes the pot needs stirred)

If someone strongly states something that I disagree with on the internet, should I engage?
What are reasons I might engage?
What are reasons I should not engage?

For me personally, there are at least 3 'good'(non necessarily moral) reasons I might engage.
1. They made themselves dis-likable, and I want to puff up my ego by making them look stupid. (likely end up doing it to myself instead)
2. I want to enter into an open dialog on a topic that interests me with different views, in the chance I may learn something or change my own views.
3. I am concerned that misinformation may harm someone else and wish to correct it.

Reasons I should not.
1. It is the internet and not worth my time.
2. They have already demonstrated they have no desire for open dialog. If neither side is interested in learning or discussing respectfully, then what is the point?
3. There is already enough information presented against that which I disagree with, that my posting will not add any weight to the topic.

In this case, being the self-appointed impartial(because I said I was) troll... We might assume that while s/he decided it was not worth their time and enough 'proper' information was already out there, s/he still wanted to add a small amount of weight to a believed opinion without fully engaging someone who does not wish to engage, thus someone browsing with the intent to learn would not be left believing that was 'THE' only opinion out there.

Perhaps a better question would be, 'Why did you feel the need to post questioning their need to post stating they would not engage?"

When it gets down to it, any forum that has an established community plays a 'game' of dancing within the rules, of defining 'cliques', and picking sides.
As a moderator you are fully aware of that and playing the game with your own post

[Adelie]

Originally Posted by goboatingnow

“engines are the abomination of sailing .. and should never be used “

Seriously . Chill out. These days the Diesel engine is probably the most reliable thing on the boat.

The first thing people will do is reach for the starter button

When you have a very suitable “ tool” you use it.

Most “ sailing boats “ are part time mobos these days . That’s the reality , live with it and move on.

“Reality” will change eventually. He wants to change it sooner rather than later.

Just because a tool is suitable doesn’t mean it is appropriate in all cases.

[jbinbi]

Originally Posted by Adelie

“Reality” will change eventually. He wants to change it sooner rather than later.

Just because a tool is suitable doesn’t mean it is appropriate in all cases.

Very well said.

The issue myself and others have is that some posters have holier than thou opinions of how everyone should do things and that their way is the only way.

I don't mind hearing of how others accomplish and live. Some is great info, gives me new ideas, or certainly pause for thought. But until you walk a mile in my shoes, don't tell me how your way is the only way to do things.

If your lifestyle, personality, and experience allow you to sail without using any fossil fuel, fantastic. I appreciate it. But just maybe, not everyone can live like that, or at least currently.

The only thing that is constant is change.

[Adelie]

Originally Posted by Narfi

….

In this case, being the self-appointed impartial(because I said I was) troll... We might assume that while s/he decided it was not worth their time and enough 'proper' information was already out there, s/he still wanted to add a small amount of weight to a believed opinion without fully engaging someone who does not wish to engage, thus someone browsing with the intent to learn would not be left believing that was 'THE' only opinion out there.

Perhaps a better question would be, 'Why did you feel the need to post questioning their need to post stating they would not engage?"

When it gets down to it, any forum that has an established community plays a 'game' of dancing within the rules, of defining 'cliques', and picking sides.
As a moderator you are fully aware of that and playing the game with your own post

Your not much of a troll, believe me the mods deal with some real trolls. Though I do see the humor in declaring yourself such.

If JM had wanted to lend support to the consensus opinion he could could have posted “I support the consensus opinion that to use a Diesel engine when I feel like it is not immoral.” Instead what he wrote indicates that SeanD’s position is too looney, or stupid or ??? to bother engaging on its merits which implies SeanD is too.

Likewise calling somebody a troll is an insult, it discounts that member and their opinion without engaging any of the merits of their opinion.

I did not think the rudeness of the post was rude enough to delete and sanction, but I didn’t want to let it go unremarked. I believe it is more often productive to ask a leading question than to directly tell somebody they are being rude.

I do not believe that most members are playing a game skirting the limits of the rules, I think most exercise the usual courtesy they use in person and don’t know clearly what the rules are or even that there are written rules. There are a few members that play chicken with the line on rudeness but not many.

Other than the moderators I don’t really see any strong cliques here. PMs aren’t normally enough social interaction for strong bonds to form. The moderators interact a lot in the background coming to a consensus on whether a post should be deleted and what sanction should be applied and we talk about what’s going on in our real lives so strong bonds have formed despite the fact that we are so spread out.

That said I think their are groups whose interests coincide so they wind up posting in the same threads.

[Adelie]

Originally Posted by jbinbi

Very well said.



The issue myself and others have is that some posters have holier than thou opinions of how everyone should do things and that their way is the only way.



I don't mind hearing of how others accomplish and live. Some is great info, gives me new ideas, or certainly pause for thought. But until you walk a mile in my shoes, don't tell me how your way is the only way to do things.



If your lifestyle, personality, and experience allow you to sail without using any fossil fuel, fantastic. I appreciate it. But just maybe, not everyone can live like that, or at least currently.



The only thing that is constant is change.

Yep we have posters expounding their holier than thou opinions, and people that are abrasive, people with skewering critiques and people who feel their opinions are the only correct opinions.

Depending on exactly how any of those are expressed they may be insultingly rude or they may just be harsh.

More broadly we all live in a society with others. Regardless of how isolated some of us may be we all depend on being part of a larger society to survive. Old tribes of Inuit or aborigines or bushmen may come close to being an exception, but even they depend on their tribes which is a very small society. As a member of a society my actions affect others, even at a great distance just as theirs affect me. As such both sides have a right to their opinions about the others actions and to a certain extent a say in those actions. My say in your behavior is primarily thru the US government just as as yours is. You don’t need to walk in my shoes to have an opinion about my choices or an effect on them whether I like it or not.

[JustMurph]

Originally Posted by Adelie

If JM had wanted to lend support to the consensus opinion he could could have posted “I support the consensus opinion that to use a Diesel engine when I feel like it is not immoral.” Instead what he wrote indicates that SeanD’s position is too looney, or stupid or ??? to bother engaging on its merits which implies SeanD is too.

Let's go with looney. Sean is most certainly not stupid, I love what he's doing with different propulsion ideas and I absolutely respect someone that prioritises the purity of sailing.

I most certainly do not respect a person who tells me my boat is broken and I lack seamanship, because I can't raise the main on my 48' boat in less than 15 seconds. That along with many of his other assertions were ludicrous and disrespectful. Prior experience has shown that a sensible answer gets another 5 paragraph diatribe of the same. That's not worth it. I'm not retired and I certainly have better things to do with my time.

I will continue to skirt around the edge of the rules and call out BS when I see it and you will continue to be displeased about it.

[catsketcher]

Originally Posted by smj

Catsketcher, if you went with the electric drives, would you use saildrives or would you use some form of stern drive that you could pull clear of the water while sailing?
Guess there are advantages to both. The saildrives may give you regen and the stern drives less drag for better sailing.

I have made four different engine setups for my cat. A pivoting nacelle with single Honda 25, a non pivoting nacelle and single 4 stroke Yammie 25 big foot, a pivoting nacelle with the Yammie and now two pivoting till bridgedeck flush nacelles, one with the Yammie 25 and one with a 9.9. (I don't need any more power, just manouvring and nicer nacelle installations). The new setup works really nicely.

I would be loathe to give away the ease of use of pivoting legs. The cost of nice folding props starts at about $2500 which is a bit of a killer before I buy anything else. I can buy an aircooled 6Kw generator for that.

Electric intrigues me. I would love to be greener but I would really like to be able to play around the outer reefs an never worry about fuel. But then again, I don't worry about fuel much now, because we don't use much.

I am interested in Sean's massive prop. I look back at our propwash and look at all the energy made into pushing a tube of water backwards fast and I want more efficiency. As I am not going to sell my boat I could make my own propulsion system. Fastback catamarans had really interesting single diesel installations. The had a large diesel mounted East West in the cockpit. A circular flange was made up for the gearbox so it could rotate at the back of the motor instead of being bolted on. The saildrive leg was extended by a fibreglass section and then the end of the leg was attached (at 90 degrees to the rest of the motor) to the glass leg. Really clever bit of kit, allowing a massive prop and deep immersion.

I would be interested in plonking an electric on top of a glass leg that had a nice saildrive or large outboard gearbox on the bottom. It is not hard to make hinges out of glass and then you can get a nice large prop and have no drag under sail. As the electric motors are small I would gain some space inside the current compartments but probably have to install a 5kW generator in the cockpit for long distance cruising, but not daysailing.

[catsketcher]

Originally Posted by donradcliffe

Catsketcher's comments on overreving confused me until I realized he is currently running outboards. His plans for an electric plus diesel generator make a lot more sense now.

Don, I am a Physics teacher, boat builder who is trying to understand props. I can't find much on prop efficiency on boats but there is a fair bit on planes. Fixed pitch props are found only on smaller and less efficient planes.

We have had diesel boats in the family and I remember when we were getting new props for the family cat we had to check that the Yanmars could get up to the correct revs, but not go over. We sent the new folding props off to get some reshaping when the Yanmars couldn't get to full revs.

The props were adjusted to give us full revs, but in a calm. This is when we tested the props. Maybe we should not have tested them this way but this is what we did.

Then in that boat, and in all our other family boats, most the time we wanted full revs was in demand of stressful situations where we were going full (or close to) reverse or forward when docking or pushing into headseas when crossing bars (We did a lot of bar crossings and pushing into headwinds in the family cat)

I would love someone who knows lots to tell us about the efficiency of props when we test them full power in a calm and then use them at near full power in different situations. We may have tested the props incorrectly but I remember there was a fair bit of back and forth back between us and the prop makers in the day.

[BigBeakie]

I am interested in Sean's massive prop. I look back at our propwash and look at all the energy made into pushing a tube of water backwards fast and I want more efficiency.

Cat;

As in many things in life, there is wisdom in moderation. And so it is with propping electric motors. When I was deciding on props for our cat with a 20kW electric motor and a 34kW diesel engine, I investigated this quite a bit. I had some lengthy and detailed discussions with people expert in prop design, props for electric motors, manufacturers of props, and custom prop makers. I must admit I started with a concept somewhat like Sean, ie that putting a really big prop on the electric was a good thing, for efficiency reasons. More thrust with less energy used, etc, etc. He states something to the effect that electric props should be 6 times larger diameter than what is usually used. In my case with 17" prop that's a prop that is 8.5 feet diameter!!! I see some "significant issues" with that extremism.
For starters, think about the propshaft angle needed to keep the tips away from chopping a hole in your hull? Which angle is the water flowing? (Hint: DOWN)

However the reality of grossly oversize props is somewhat different. Yes, it is true the additional low down torque CAN turn a bigger prop.....at a slow RPM, and result in slow speed with lots of thrust. If that is ALL you want/need to do, it has some merit. You will motor at very slow speeds, and I mean very slow even in a calm. When you motor against a big wind/tide, the motor will just keep turnin that huge prop at the same RPM, and your motor will overheat.

FYI, a little anecdote. In Europe, there was a German fellow who is acknowledged as a genius of prop design. He was the guy who designed the revolutionary props for the WW2 U-boats, among many other applications later, of course. He was involved in the early prop design and IP transfer to Oceanvolt for electric motors, as I understand it.

If seriously bigger props were feasible on the water cooled OV motors, they would use them. They don't.

[jmh2002]

I just thought I would throw some links up in this thread that may be interesting to readers here about a Gunboat 60 with a Torqeedo Deep Blue Hybrid system installed.

Since April 2018 the boat has done around 40,000nm with this system installed, including several trips to New England, the Bahamas and Caribbean as well as Atlantic, Pacific, and Indian Ocean crossings.

They have worked closely with Torqeedo including prototyping and testing and seem to be pretty happy with the overall outcome.

With 2 people onboard, a fully electric boat, including the galley and all normal comforts (but not including running aircon 24/7), on average they seem to only need to run the genset every 3-4 days for 45mins.

Add more people onboard or more aircon runtime and you can estimate a proportionally higher genset use of course (although in some cases their batteries may have already been full, so maybe allowing more regen or solar input could mitigate extra genset runtime).

Although they have also done a couple of passages in ideal conditions without running the genset at all.

- Saint Martin to Turks and Caicos, around 600nm
- Martinique to Panama, around 1200nm

Other times in light air they have also found (electric) motor sailing to be a very efficient option too: "We often just assisted with about 1 KW of power to get a couple of knots of speed to assist the sails"

Yes this is a big budget operation, and on a Cat that sails extremely well, but it also really showcases what is possible (and what isn't...) and I think the feedback from several years and a lot of miles is pretty interesting.


11 May 2018 Moonwave – Deep Blue Hybrid System
Moonwave - Deep Blue Hybrid System - MOONWAVE - Gunboat 60 Catamaran

19 August 2018 - Moonwave – Torqeedo talking about our new system
Moonwave - Torqeedo talking about our new system - MOONWAVE - Gunboat 60 Catamaran

07 May 2019 - One year feedback of the new Hybrid System
One year feedback of the new Hybrid System [May 2019] - MOONWAVE - Gunboat 60 Catamaran

18 july 2020 - Lifeaboard, Lockdown & Autonomy
Lifeaboard, Lockdown & Autonomy [March to July 2020] - MOONWAVE - Gunboat 60 Catamaran

"Here are some facts that we have learned from our 90 days at anchor and 26 days at sea sailing [Panama to Costa Rica, Costa Rica to Galapagos & Galapagos to Marquesas Islands] without touching land and contact to local populations:

Our solar installation was a great plus for our energy balance on board. Depending on the hours of sun [rainy season less effective] the generator only ran for 45min every 3 to 4 days. This included electric cooking, baking bread, water maker and washing machines with no restraining needs for 2 persons."

28 May 2021 - Let’s talk “Hybrid System” – three years later
Let's talk "Hybrid System" - three years later [May 2021] - MOONWAVE - Gunboat 60 Catamaran

(I have no connection at all, so this isn't a promotion of any kind)

[Adelie]

BigB: A large diameter prop would not be angled down significantly because it wouldn’t work on your vessel with your drive train; it would need to be modified so the shaft exited horizontally partway or most of the way down the keel fin. This would involve a belt or chain drive, a V- or Z-drive. Or it would need to be part of an outboard system.

All: Sean is using large diameter RC aircraft props. These have long skinny blades, aka high aspect. That high aspect is part of the efficiency advantage he is getting.

The other advantage is using a slower turning prop. A prop, or wing for that matter, experiences at least 2 types of drag, friction drag and lift induced drag. Creating propulsion force creates drag, just as a wing does. There is some relationship between lift and drag, I believe it is linear or nearly so but I really haven’t looked that up.

Friction drag occurs in-proportion to the velocity of the water over the surface, I believe as a power function, and the area of the blade I believe in a linear relationship. Even if the blades had zero pitch and therefore no thrust spinning the prop would have resistance fire to skin friction and that drag would increase by some power in relation to rotational speed.

All the math works out such that a larger prop with more area turned at a slower rate creates less rotational drag (ie requires less power to turn) for a given thrust.

A larger diameter prop has functional considerations that have nothing to do with propulsive efficiency; considerations such as shaft angle, blade clearance to hull, blade area.

The props Sean is experimenting with could not be scaled up to drive a boat at hull speed.
A. While there are probably larger RC props that could be used, they may be custom and would quickly become prohibitively expensive.
B. Being carbon fiber they are subject to erosion from minute particles in the water. As rotational speed increases so will wear.
C. Regardless of the particulate matter in the water if rotation speed increases enough there will be cavitation which causes blade erosion of a different nature.

My guess is that you could get somewhere around 3kt boat speed using 700W in a 10-12,000lb monohull. In might require using a 4- or 5-blade prop to get enough blade area so you get enough
Thrust while turning slow enough to avoid cavitation. I would guess that at about 4kt you would be starting to cavitation even with 5-blades.

To push a boat like that to hull speed would require metal blades.

Campbell sailors are on this track, they just haven’t pushed the extreme because nobody has the appropriate gear ratio in their existing transmissions, they would need a custom tranny.

[goboatingnow]

Originally Posted by Adelie

“Reality” will change eventually. He wants to change it sooner rather than later.

Just because a tool is suitable doesn’t mean it is appropriate in all cases.

A tool is suitable but not appropriate …..There’s a contradiction

[BigBeakie]

JMH,

Thanks for posting that, some really good perspectives from EP owners after 3 years cruising and 40,000nm.

The takeaway line for me was;

" From our point of view one of the advantages of an hybrid boat compared to a more classic diesel boat installation is that it’s an easier way to manage your power onboard. But if you plan to use your sailboat like a motor vessel and like to turn the engines on as soon as your speed drops to 5 knots to do 6 knots plus under power, than this is not for you. In a way it challenges you to put the sails up and become a better sailor [in a good way]. "