The rise of electric Boats

[danstanford]

Originally Posted by Emoyeni

Not trying to add to the flame war but.... I’m seriously wondering how many of the people pointing out the negatives of electric have done cruising on an electric boat or even set foot in one? Again I don’t mean this in a mean way, just would like to hear from more people who have gone electric, have any of you regretted it?

I am one of the participants who actually has an electric boat so I suppose that adds a certain bias or defensiveness to my responses. Ultimately, from my point of view, cruising with an electric boat will require some significant compromises over cruising with a diesel. The flame-ups commence when someone either says it is impossible to do, or claims there are no compromises.
What escapes most analytical thinking on the topic is the differing values we may have. For some the dollars are paramount while for some the novelty of doing something different and which feels good offsets the dollars. For some the convenience is paramount and for others the feelings of virtue can mean they actually celebrate the occasional lack of convenience.
My boat is not a cruiser but if it were and I were cruising with it I would not hesitate to invest in a generator so that I could go electric the vast majority of the time and have the option of having to not make the compromises when it was important to get there right now. In day to day operation the Oceanvolt system in my boat is fantastic and represents not one whit of compromise over having a diesel instead until range becomes the consideration.

[Emoyeni]

Thanks for your thoughts - I agree I think a lot of the arguing happens when people assume their values are a universal truth and that you having different ones somehow makes mine wrong.

Originally Posted by danstanford

I am one of the participants who actually has an electric boat so I suppose that adds a certain bias or defensiveness to my responses. Ultimately, from my point of view, cruising with an electric boat will require some significant compromises over cruising with a diesel. The flame-ups commence when someone either says it is impossible to do, or claims there are no compromises.
What escapes most analytical thinking on the topic is the differing values we may have. For some the dollars are paramount while for some the novelty of doing something different and which feels good offsets the dollars. For some the convenience is paramount and for others the feelings of virtue can mean they actually celebrate the occasional lack of convenience.
My boat is not a cruiser but if it were and I were cruising with it I would not hesitate to invest in a generator so that I could go electric the vast majority of the time and have the option of having to not make the compromises when it was important to get there right now. In day to day operation the Oceanvolt system in my boat is fantastic and represents not one whit of compromise over having a diesel instead until range becomes the consideration.

[valhalla360]

Originally Posted by Emoyeni

Not trying to add to the flame war but.... I’m seriously wondering how many of the people pointing out the negatives of electric have done cruising on an electric boat or even set foot in one? Again I don’t mean this in a mean way, just would like to hear from more people who have gone electric, have any of you regretted it?

Do a search for "GrowleyMonster" posts. He's built his own and has been using it for a while so he has good insight.

The nice thing is, while he is a proponent of electric drives he doesn't fall prey to the magical thinking so many proponents have. He openly admits the limitations and problems with battery electric propulsion in addition to the positives he's found.

The problem with completely discounting those who haven't taken the leap...removes the thoughts of those who have looked and seen the jagged rocks just below the surface.

[Adelie]

Originally Posted by danstanford

I am one of the participants who actually has an electric boat so I suppose that adds a certain bias or defensiveness to my responses. Ultimately, from my point of view, cruising with an electric boat will require some significant compromises over cruising with a diesel. The flame-ups commence when someone either says it is impossible to do, or claims there are no compromises.

....

There other thing that sets off some folks is the safety argument. “It’s not safe without an large engine. You are endangering your crew and others. It’s not responsible.”

On the face of it I agree that not having an engine is less safe for well experienced sailors though not dangerous per se.

[Adelie]

Originally Posted by valhalla360

....



The problem with completely discounting those who haven't taken the leap...removes the thoughts of those who have looked and seen the jagged rocks just below the surface.

The imagery of jagged rocks is an emotional appeal supporting one point of view and implying that the folks who disagree haven’t considered all the problems or are to stupid to do so. Oddly enough that’s what you were decrying in the first half of the above sentence. Ironic.

[valhalla360]

Originally Posted by Adelie

There other thing that sets off some folks is the safety argument. “It’s not safe without an large engine. You are endangering your crew and others. It’s not responsible.”

On the face of it I agree that not having an engine is less safe for well experienced sailors though not dangerous per se.

I get what you are saying but there is a combination of current expectations and capability that are coming into play...and a healthy dose of semantics.

Most people would argue it's unsafe to remove the seat belts and air bags from your car...of course, I haven't been in a crash where they would have made a difference in the last 50yrs...so does that mean I should remove them to cut weight and improve fuel efficiency?

The current standard is a healthy well powered engine that can put out max power for hours. 100 years ago, that would have been an expensive addition to a small cruising boat that would have required specialty knowledge to keep operational...and even well maintained, they weren't nearly as reliable as modern engines.

So in terms of semantics, you can play at the idea you are only reducing safety but not making it dangerous but for the most part it's the same thing just how you phrase it.

The real question is: How less safe is the trade off?

PS: I do agree we can take the idea of improving safety to silly levels at times and there is no definitive answer as to what is right.

[valhalla360]

Originally Posted by Adelie

The imagery of jagged rocks is an emotional appeal supporting one point of view and implying that the folks who disagree haven’t considered all the problems or are to stupid to do so. Oddly enough that’s what you were decrying in the first half of the above sentence. Ironic.

Not at all. There may be places to jump in where there are no jagged rocks. By having dissenting views, it's more likely that we hear about both sides.

A great many of the electric propulsion proponents treat it almost as an article of faith, discounting or ignoring the downsides. By hearing both sides of the argument, someone new coming in sees them either point out the safe places to jump in or it quickly becomes obvious, they are taking a position of faith not fact.

Example: If you use your dingy for short range slow speed operations, it makes a lot more sense to get a good trolling motor rather than a 2hp gas motor most of the time. Little or no impact on capability. Easy to set up to recharge from the motherships electric system (or shore power when available). Drastically simpler to maintain and more reliable. Electric power wins...but you have to look at the use case. If you often use the dingy for 10 mile runs at 20mph, the answer changes.

[misfits]

Originally Posted by Emoyeni

Not trying to add to the flame war but.... I’m seriously wondering how many of the people pointing out the negatives of electric have done cruising on an electric boat or even set foot in one? Again I don’t mean this in a mean way, just would like to hear from more people who have gone electric, have any of you regretted it?

Do I regret going electric? Nope!
Are there circumstances when I wish I had a ICE, absolutely. But I don't miss the fuel docks, smell of diesel exhaust, the mind numbing drone of the engine.
Are there range limitations, yes. But I've also have the capability to "motor" the floating cabin should the need arise with assistance from a Honda 2200 watt generator.

I've had powerboats for the last 40 some years, this is my first sailboat. One of the things I've noticed about sailboaters, if they can't sail @ 4-5 knots or more cause the wind isn't blowing hard enough or from the wrong direction of the destination, they motor with the hammer down. Perhaps this mindset along with the range anxiety associated with electric is a contributing factor to negativity.

If we were all vanilla life would be pretty boring .
For me defecting to the sailboat side of the equation & going electric has been a fun science experiment.

Now wtf is with all these pop up adds on this site?

[danstanford]

Originally Posted by valhalla360

So in terms of semantics, you can play at the idea you are only reducing safety but not making it dangerous but for the most part it's the same thing just how you phrase it.

The real question is: How less safe is the trade off?

The only time I have had to sail into the basin and on to the dock was when a diesel let me down! In addition, look at most accounts of disasters caused by engines not working and you will see diesels not running at the time they are needed most...mostly because the big waves stirred up the junk in the fuel tank.
Does this make diesels unsafe or less safe than electrics? Of course not but the hyperbole around the dangers of electrics are just as specious.

[Yihang]

This is turning in a covid-19 thread.

I think everyone here agrees electric is good if not better than a diesel for scenarios where you don't anticipate motoring for long distance, and where you can plug into shore power for charging or have a generator as backup.

I think it's also simple physics that a hybrid drive where a generator is sized to provide continuous drive is not as efficient as a direct diesel drive.

I think everyone in this thread known the benefits and limitations of electric drive. It's simple numbers.

[BigBeakie]

Originally Posted by Yihang

This is turning in a covid-19 thread.

I think everyone here agrees electric is good if not better than a diesel for scenarios where you don't anticipate motoring for long distance, and where you can plug into shore power for charging or have a generator as backup.

I think it's also simple physics that a hybrid drive where a generator is sized to provide continuous drive is not as efficient as a direct diesel drive.

I think everyone in this thread known the benefits and limitations of electric drive. It's simple numbers.

OK, since you feel the analysis is simple numbers, tell me how many hours of motoring on say a 45HP diesel running at around 2,000 rpm would represent the crossover break even cost compared to a 16kW DC genset for:

A. Propulsion alone
B. Lithium battery charging.

Assuming a 16kW (continuous) DC genset runs at 3 liters diesel per hour and is about equal to an alternator putting out 1,333 Amp Hours. (16,000 watts/12 volts)

How many engine hours are you assuming per year, propulsion vs battery charging, and total?

After this simple exercise, do you still feel the DC genset is not as efficient?

[Yihang]

Originally Posted by BigBeakie

OK, since you feel the analysis is simple numbers, tell me how many hours of motoring on say a 45HP diesel running at around 2,000 rpm would represent the crossover break even cost compared to a 16kW DC genset for:

A. Propulsion alone
B. Lithium battery charging.

Assuming a 16kW (continuous) DC genset runs at 3 liters diesel per hour and is about equal to an alternator putting out 1,333 Amp Hours. (16,000 watts/12 volts)

How many engine hours are you assuming per year, propulsion vs battery charging, and total?

After this simple exercise, do you still feel the DC genset is not as efficient?

Why does everyone always go on the defensive. I actually think electric propulsion would work for most people and even myself. But seems like either side cannot accept there is a middle ground. It's either you are against us or you are with us.......sounds like a familiar phenomenon these days.

I said it would be less efficient to power an electric motor continuously using a diesel generator than using a direct drive diesel engine. I think you will agree with that.

I never said a Genset is not as efficient as an alternator.

A 16 KW Kohler is about 400KG. a 45HP Yanmar is 220KG. In a boat that would only require a 45HP motor a 16KW generator presents a problem.

[BigBeakie]

Originally Posted by Yihang

Why does everyone always go on the defensive. I actually think electric propulsion would work for most people and even myself. But seems like either side cannot accept there is a middle ground. It's either you are against us or you are with us.......sounds like a familiar phenomenon these days.

I said it would be less efficient to power an electric motor continuously using a diesel generator than using a direct drive diesel engine. I think you will agree with that.

I never said a Genset is not as efficient as an alternator.

A 16 KW Kohler is about 400KG. a 45HP Yanmar is 220KG. In a boat that would only require a 45HP motor a 16KW generator presents a problem.

I'm not being defensive, I was asking you to think about the statements you make. Specifically that ipso facto, a diesel motor is more efficient for continuous motoring. Even Nigel Calder concluded than when alternative sources of energy are taken into consideration, a hybrid electric can use less fuel for a given distance.

The point I was trying to make is that the assumption that a diesel engine is the most efficient for motoring only holds true for a motorboat, a motor cruiser. Or, a sailboat that cannot sail that well so the owner relies on the engine when the wind is up, or when the wind is light.

For a reasonable sailboat that can actually sail in both moderate and light winds, the amount of time needing to motor for long periods is pretty minimal over a year period. And for those minimal periods, an electric boat can be just fine.
For long distance cruising/passagemaking, a hybrid using a DC genset can provide a stop gap solution AND provide superior battery charging.

So if you motor on the DC genset in such a way to also be replentishing the batteries, and then stop the genset and continue to electric motor for a period, and repeat that cycle, you may find that the diesel that has to be fed fuel the entire time may not be as efficient. Plus if you charge batteries with the diesel propulsion engine, and count that fuel used, it pales in comparison to the output from a comparable DC genset. I don't care how beefy an alternator you install.

And citing a 400 kg genset for an EP boat is just silly. Why would anyone use that instead of a FP, Eniquest or other modern DC genset? My 16kW DC genset is 175 kg.

If you add in solar to the equation, the diesel falls even further behind. A well set up EP boat with good solar array can motor through the calms on solar alone, not even touching the battery reserve. In the tropics, this can represent a very large block of time spent solar motoring.

A diesel can't do that, can it?

And a diesel NEVER returns to port after motoring with more fuel than it left with. But an EP boat can. It can sail and motorsail and get back to the dock with more charge in the batteries than when it left. Cornell sailed 10 hours at 8.2 knots average and had a nett increase of 5.3 kW in the batteries. So the OV EP ran the boat power all day ( of very heavy useage, at least a kW per hour, by the way) AND still put 5.3kW into the tank by the end of the trip. Is this not pretty good???

So to figure out which boat is actually more efficient, you have to do the math. That's all I'm saying.

[Yihang]

Originally Posted by BigBeakie

I'm not being defensive, I was asking you to think about the statements you make. Specifically that ipso facto, a diesel motor is more efficient for continuous motoring. Even Nigel Calder concluded than when alternative sources of energy are taken into consideration, a hybrid electric can use less fuel for a given distance.

The point I was trying to make is that the assumption that a diesel engine is the most efficient for motoring only holds true for a motorboat, a motor cruiser. Or, a sailboat that cannot sail that well so the owner relies on the engine when the wind is up, or when the wind is light.

For a reasonable sailboat that can actually sail in both moderate and light winds, the amount of time needing to motor for long periods is pretty minimal over a year period. And for those minimal periods, an electric boat can be just fine.
For long distance cruising/passagemaking, a hybrid using a DC genset can provide a stop gap solution AND provide superior battery charging.

So if you motor on the DC genset in such a way to also be replentishing the batteries, and then stop the genset and continue to electric motor for a period, and repeat that cycle, you may find that the diesel that has to be fed fuel the entire time may not be as efficient. Plus if you charge batteries with the diesel propulsion engine, and count that fuel used, it pales in comparison to the output from a comparable DC genset. I don't care how beefy an alternator you install.

And citing a 400 kg genset for an EP boat is just silly. Why would anyone use that instead of a FP, Eniquest or other modern DC genset? My 16kW DC genset is 175 kg.

If you add in solar to the equation, the diesel falls even further behind. A well set up EP boat with good solar array can motor through the calms on solar alone, not even touching the battery reserve. In the tropics, this can represent a very large block of time spent solar motoring.

A diesel can't do that, can it?

And a diesel NEVER returns to port after motoring with more fuel than it left with. But an EP boat can. It can sail and motorsail and get back to the dock with more charge in the batteries than when it left. Cornell sailed 10 hours at 8.2 knots average and had a nett increase of 5.3 kW in the batteries. So the OV EP ran the boat power all day ( of very heavy useage, at least a kW per hour, by the way) AND still put 5.3kW into the tank by the end of the trip. Is this not pretty good???

So to figure out which boat is actually more efficient, you have to do the math. That's all I'm saying.

It's a wonder why more people are not using this wonderous technology.

10 hours of sailing at 8 knots with two ocean volts netting 5.3KW does not seem like it would do a lot if they needed to motor. They also pretty much max out on solar for a boat of that type.

Again there are use case scenarios where EP makes sense but making it sound like a silver bullet without admitting any of it's shortcoming isn't doing EP any favors. It makes the EP people look like evangelicals.

Anyway. You are arguing with someone who actually like EP and wants to use it.

[double u]

"... doing something different and which feels good offsets the dollars. For some the convenience is paramount and for others the feelings of virtue can mean they actually celebrate..."

while being a valid sentiment on your own boat, this type of thinking seems to lead society along very harmful paths trying to solve pressing environmental problems..."feeling good" will not solve any climate issues...