Jimmy Cornell goes Electric, with a Cat

[Dockhead]

Originally Posted by sailingharry

Adelie,


Curious where you get your GPM/hp numbers. If they are credible, it's really useful information.


I'm a little skeptical though (and with the research you do, I'm only a LITTLE skeptical, because you don't talk rubbish!).


I was for a few years overpropped, then under propped, and then finally got a Kiwi and dialed it in. But getting useful historical information on actual numbers when you use less than 50 gallons a year is challenging. Still, I was getting fairly consistent .5 GPM.


Now I've got a new boat, with a 55HP motor. I'm about perfectly propped -- I am about 100 RPM below redline at WOT. I run at least 80% redline routinely, yet I consume under 1GPM -- does that mean I'm running under 50% HP? I realize that actual HP is dictated by the load, not the available HP at a give RPM (just like Amps from an Alt are determined by what the battery will take, not what the alt will give). But that raises questions about the power vs speed curve, which we know is very hockey-stick shaped. Perhaps it takes the full 55 HP to give me 7.5kts, and my cruising speed of 7kts only takes 15 HP -- not beyond the realm of reason! But I'm not going to run multiple consumption experiements -- run 10 hours at WOT, refill tanks and calculate, run 10 hours at 90%, 80%, etc. To get 10 hours on my engine will include no-load battery charging, light load anchor up/down, harbor passages, etc, making it hard to suss out the actual consumption.



It sure would be wonderful if you could put useful instrumentation on a diesel for less than ridiculous cost. I'd love to see instantaneous GPH, so I could do MPG calculations on the fly. But I can't find them for less than $thousands.

You guys ever heard of a propeller curve?

The consumption curve only gives you consumption at max available power for a given rpm. Propeller curve shows how much power a typical fixed pitch prop takes at different rpms.

Adelie's method is better, but a prop curve will get you pretty close.

[Adelie]

Originally Posted by seandepagnier

....

The issue here is to be "comfortable" is really a disguise for refusing to use the sails in all possible cases and to be patient when there is calm. If you can do this, you can still be comfortable. So this is a mindset and perspective that needs to change, not an increase in battery storage density.
That is my opinion too generally.

I get all 3 of these by a wood stove. I throw stove away at end of winter and build a new one in november every year, it takes about a day to build one. I can cut enough wood for a week in less than an hour, and this type of heat reduces humidity in the boat a huge amount. It is also the safest and cheapest and really the only viable way I have found to heat the boat without using fuels (which are worse anyway even if this were not cheating)
Do you have photos of your stove design? Would love to see it.

I also have an evacuuated tube solar oven and it cooks even when it's below freezing, but takes twice as long as a hot summer day. I'm surprised thses are not more common, because in the summer months, it is the only thing I needed for cooking and really it's quite small and not expensive, and it is also self-cleaning because it's always on so it burns anything left inside into dust like a cleaning cycle.
Was planning on getting one of these too.

Everything you put inside a refrigerate doesn't taste as good, and it degrades the quality and freshness of food. There are much smarter ways to preserve food that don't require continuous energy. I would not want a refrigerator even if it were for free and did not use any energy.
Plenty of folks want refrigeration, I ain't even going to try talking them out of it. Bigger fish to fry at the moment.

You are not considering that only about 25% of the energy used to make the butane is available in the butane since most of it is consumed in the refinery, compression and transportation of the fuel and all the infrastructure required to support that. despite this, your figures of 50% or 75% show that neither system is very efficient. Both could have better than 90% efficiency but this is just now how most systems are designed.
I have no idea how you would get 90% efficiency from a butane burner, please explain. I know how to get 90+% efficiency heating water: electric kettle, the only source of inefficiency is energy spent heating the mass of the kettle, very little lost to environment.
Regardless, the point of my post was to show that an electric galley is technically and realistically feasible depending on size of boat and willingness to mount enough solar to power this.

If you are actually comparing using propane/butane for cooking (which is basically stealing from future generations) when there are plenty of alternatives available, you might as well compare the efficiency and cost of using slaves to row your boat around for propulsion and consider all the other useful tasks they could do for you without considering any moral implications.
Going over the top like this doesn't help convince folks of your position.

See above comments in RED.

[Adelie]

Originally Posted by wingssail

Yanmar 3JH2E, 35 Continuous HP, 38 Maximum. At 2000RPM Yanmar suggests it is producing about 20 HP.

We have a 2.83:1 (non-standard) reduction gear and a 2 blade 18" diameter 17" pitch propeller, both of which affect how much speed we get for a given engine RPM. This reduction gear allows a much slower shaft and propeller speed.

Our vessel has a very easily driven hull form. At 2000 RPM (20 HP) we get a speed of 5.8 knots and use .57 gallons of fuel per hour for 10 nautical miles per gallon.

This works out to be about 35hp/gal at 2000RPM.

I believe that it would take 15000- 16000 watts to propel our boat at 5.8 knots, an easy cruising speed.

Are you sure it's a 2E? This site indicates that 2E was 34hp max and 3E was 38hp max. Not saying the site is right and you are wrong, was just trying to find curves to look at and noted a mis-match.
https://boatdiesel.com/Engines/Yanma...1916/index.cfm

Are you pulling hp at a given rpm off the engine curve or the prop curve?
The engine curve shows what the engine is capable of producing at a given RPM.
The prop curve shows what the "ideal" prop is capable of absorbing for a given RPM.

Regardless, thanks for the info.

[aqfishing]

Check out this shaft generator. They say they averaged 40 amps each while sailing. Obviously you cannot do this with a saildrive. Not sure how many watts that is.


https://youtu.be/INoBCaTpEvg

[wingssail]

Originally Posted by Adelie

Are you sure it's a 2E? This site indicates that 2E was 34hp max and 3E was 38hp max. Not saying the site is right and you are wrong, was just trying to find curves to look at and noted a mis-match.
https://boatdiesel.com/Engines/Yanma...1916/index.cfm

Are you pulling hp at a given rpm off the engine curve or the prop curve?
The engine curve shows what the engine is capable of producing at a given RPM.
The prop curve shows what the "ideal" prop is capable of absorbing for a given RPM.

Regardless, thanks for the info.

No, it's a 3JH2E. I'm looking at the "JH2" document that came with it. Inside it gives the following numbers:

• Continuous Rating output-35/3400 RPM
• Maximum output (crankshaft)-38/3600RPM
• Maximum output (propeller shaft) 36/3600RPM
  
  The propeller power output curve shows 8hp at 2000RPM
  

I'd scan the document (which has the curves) but Judy is sleeping on the scanner right now.

[Dave_S]

Originally Posted by aqfishing

Check out this shaft generator. They say they averaged 40 amps each while sailing. Obviously you cannot do this with a saildrive. Not sure how many watts that is.


https://youtu.be/INoBCaTpEvg

It doesn't say anything ! There was no voiceover or text. But assuming it is 12Vdc at 40amps is 480W.

[aqfishing]

Originally Posted by Dave_S

It doesn't say anything ! There was no voiceover or text. But assuming it is 12Vdc at 40amps is 480W.

Could be a 24v alternator.

Is that 480/960 watts an hour?

[Dave_S]

Originally Posted by aqfishing

Could be a 24v alternator.

Is that 480/960 watts an hour?

Yes, Volts X amps = Watts

Sorry, Watt hour or Wh is a unit of energy so if you have 480Wh of energy stored you have enough energy to use 1W for 480 hours, 480W for 1hour or any other variant.

[harlem24]

Not sure what Jimmy and crew did differently but the system seems to work...

https://www.youtube.com/watch?v=jpAnGJpcnQU

With generation of about 1kW and more with two motors.
Or they really had huge consumption...

[250224]

Originally Posted by harlem24

Not sure what Jimmy and crew did differently but the system seems to work...

Without very detailed numbers it's difficult to say.

My high level opinion is that the umas are young, curious and driven. They adapt at what they have. Mr. Cornell had 4 (or 5?) people on board, which for one needs much more energy for e.g. electric pantry. And, I'd say, they have/had more lavish expectations regarding power consumption.

I'm very pleased to see that https://cornellsailing.com/2021/01/t...ack-on-course/ continues. Maybe not as pure as initially hoped, but most likely the correct thing in his situation.

[Edit] Mmh, maybe I should add that Jimmy Cornell also seems driven and it's nice to read how they plan to adapt!

[wingssail]

Originally Posted by aqfishing

Check out this shaft generator. They say they averaged 40 amps each while sailing. Obviously you cannot do this with a saildrive. Not sure how many watts that is.


https://youtu.be/INoBCaTpEvg

I think that we should note that this is a 67' cat. If you have big sails which generate a lot of power, and big propellers to transfer that energy to the alternator (and sufficient wind) you can get some reasonable output.

Keep in mind that there apparently are two 4 cyl Yanmars to drive this boat.
Probably it takes 20 hp to attain a reasonable cruising speed under power, so that is around 1300 amps of electrical power. Getting 40 amps under regenration isn't going to do much for electrical crusing range.

[fxykty]

Originally Posted by blu3534

Without very detailed numbers it's difficult to say.



My high level opinion is that the umas are young, curious and driven. They adapt at what they have. Mr. Cornell had 4 (or 5?) people on board, which for one needs much more energy for e.g. electric pantry. And, I'd say, they have/had more lavish expectations regarding power consumption.



I'm very pleased to see that https://cornellsailing.com/2021/01/t...ack-on-course/ continues. Maybe not as pure as initially hoped, but most likely the correct thing in his situation.



[Edit] Mmh, maybe I should add that Jimmy Cornell also seems driven and it's nice to read how they plan to adapt!

I’m also very pleased that he is continuing with his project. Given that we’re shortly going to remove propane and have an all-electric galley, I’m very interested to see how he addresses the demand side with more efficient appliances. In our case an induction hob is the easy part, but we’re still unsure about the oven replacement. Currently leaning to a convection microwave. Or maybe we get a diesel oven? It makes me nervous to have an electric oven regularly running for 2 or 3 hours when we bake or roast or keep food warm.

On the generation side, he writes more solar (that’s a no brainer) and a hydro generator (presumably a Watt & Sea). Heck, he should install two W&Ss and forget about engine shaft regeneration. No talk of an ICE generator.

[Adelie]

My guess is that convection cooking won’t be so bad.
There will be a big surge of current heating thee oven up and the it will cycle off and on maintaining temp.

I know baking a 2lb loaf in a bread maker uses 330Whr. I measure that. Figure 30Ahr from a 12v including power loss at the inverter.
Baking a loaf in a convection oven will involve more losses to the environment so figure 40Ahr.

I’m actually gearing up to test power usage cooking various things. In a year or so.

I can think of at least one way to conserve power here. If you have a high mass item like a chicken that’s in the fridge, leave it on the counter for 3-4hr so it comes to ambient temp.
Let’s say it’s a 2.25kg (5lb) chicken and it rises 40F (40F->80F, 22C) that’s about 58Whr or 5Ahr at 12v.

[donradcliffe]

Originally Posted by wingssail

No, it's a 3JH2E. I'm looking at the "JH2" document that came with it. Inside it gives the following numbers:

• Continuous Rating output-35/3400 RPM
• Maximum output (crankshaft)-38/3600RPM
• Maximum output (propeller shaft) 36/3600RPM
  
  The propeller power output curve shows 8hp at 2000RPM
  

I'd scan the document (which has the curves) but Judy is sleeping on the scanner right now.

The 8 hp is consistent with your observed 0.5 GPH diesel usage. I think you could achieve your 5.8 knot cruising speed with a 5-6 kw electric motor. However, that's a lot of solar panels.

[250224]

Originally Posted by blu3534

I'm very pleased to see that https://cornellsailing.com/2021/01/t...ack-on-course/ continues. Maybe not as pure as initially hoped, ..

Must take the last part back, I misread the blog post for a diesel generator. But, as fxykty wrote, Cornell eyes a hydro-generator. This is as pure as initially hoped.