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  #21  
Old 09-10-2012
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Re: Optimal propulsion system

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Originally Posted by Jgbrown View Post

It's the last idea that I don't really understand perhaps. What is your current fuel range at hull speed? If you could have enough batteries for even 50% of that range,
That would be great but sadly is not going to happen. Most battery banks that folks are willing to pay and find room for have the fuel equivalent of less than a gallon.

The capacity of today's battery banks are amazingly low compared to fossil fuel.

In my scenario however with the usage of the boat being sailing for 3 to 6 hours then being off the boat for shore visits the charging can be done by either generator or shore power while we are off the boat.

I want the option for safety and itinerary flexibility to forget about battery limits (and our precious tranquility) and just motor for as long as our 30 gallons will take us.
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  #22  
Old 09-10-2012
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Re: Optimal propulsion system

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Originally Posted by nickmerc View Post
I had been thinking about an electric option for my Pearson 30 for if/when the A4 dies. Electric motors are very efficient. With a timing belt reduction you have almost limitless combination for matching the ideal motor rpm to the ideal prop rpm. You will find numerous posts and articles expounding on the benefits of electric propulsion so I will not go into detail here. I will say that most of the claims are reasonable accurate. The one drawback (and it is a major one) is energy storage. Batteries are just not up to the task of replacing fossil fuels... yet.

The serial hybrid approach is one way to bridge the gap at this time. While not ideal it is, in my opinion, a good stop measure. As battery technology improves the only change you will have to make is replacing the batteries and possibly the charging system.

You will have to determine if electric propulsion will work for your mission in the first place based on your distance and speed requirements. For me as a lake sailor it is a good fit. When I was on the Chesapeake Bay; not so much.

The reduction in complexity and the very small size of an electric motor required to power my boat to hull speed was remarkable. The largest expense was batteries. Both financial and physical space/weight.

As I look at daysailer to replace my keelboat (new mission requirements) I am 90% set on electric for aux propulsion.
I read recently that the technology exists for much better batteries but that the oil companies own the patents. They didn't cite anything that actually proves that but it sounds plausible or even likely. If so, it's just sad.
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  #23  
Old 09-10-2012
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Re: Optimal propulsion system

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Originally Posted by denverd0n View Post
Me too. So you adjust your expectations, don't set a schedule that has you going near hull-speed all the time, and enjoy life at a slower pace. Easy-peasy, and doesn't cost a penny.
I agree in theory but in practice it does not work for me.
Very often here in Long Island sound it can be days before the 2 knot current, the wind, sunny weather and daylight and my days off all line up so all of the above are in our favor.
A simple 30 mile passage that can take only 5 hours can easily extend to over 10 hours.
So we are left with two choices; wait all summer for a perfect day and maybe use the boat a couple times or go, with auxiliary power, and have a pretty good day.

Actually is it a lot worse than the simple choice above would suggest. The wind is so flukey that on the perfect day the wind will often die and on the marginal day the wind will fill. In either case you are committed to the trip and it is just not fun to bake for 10 hours and miss a shore dinner and not safe to try to dock in the dark.

So for the 90 percent of the days when I might just need a little boost for 4,5 hours it would be cool to fake it with electric and pretend we were sailing.

At the same time if I have to make a 300 mile passage I want to be able to do that too and keep good time and not be limited by batteries.

Last edited by davidpm; 09-10-2012 at 10:52 PM.
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Old 09-10-2012
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Re: Optimal propulsion system

Buddy of mine is halfway into a conversion from diesel to electric aboard his Aloha 32. He's going with Propulsion Marine's 5.5 kW solution. He's pretty pumped about the switchover; certainly the engine compartment has a lot more room without the engine and assorted plumbing. Batteries and a genset are part of the plan. More to come as events warrant.
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Old 09-11-2012
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Re: Optimal propulsion system

I've thought about a hybred system leaving the diesel in place then attatching an electric motor to the prop shaft with cog belt, I then could run just diesel, just electric, diesel with electric boost, diesel with recharge,
I would use electric mostly for on/off mooring, docking then diesel for passage making if sailing was not possible. would try to have enough batteries for a few hours.

For my boat I was thinking a 10-12 hp electric DC motor in 48 volts, 8 six volt golf-cart batteries, that should give me 7 hp for an hour.
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Old 09-11-2012
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Re: Optimal propulsion system

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Originally Posted by sww914 View Post
I read recently that the technology exists for much better batteries but that the oil companies own the patents. They didn't cite anything that actually proves that but it sounds plausible or even likely. If so, it's just sad.
Yea, same thing happened to the 200 mpg carburetor in the 1970's!

Though I do find it difficult to believe that we cannot get a lot better millage from cars today. After all I got way over 50 MPG in my 1980 VW Diesel and it is more than 30 years later!
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Re: Optimal propulsion system

Is something like this what you are looking for?

"www dot hybrid-marine.co.uk/5.html"

Beta Maring used to market it themselves but it looks like they have passed the marketing over to someone else. Also have one with a Yanmar.

Last edited by gbtillman; 09-11-2012 at 01:46 PM.
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  #28  
Old 09-11-2012
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Re: Optimal propulsion system

Fortunately those patents that the oil companies bought, were taken out in the 1930's. Yes, the conspiracy goes that far back and the good news is, the patents are due to run out soon!

Heard about a man in Florida who got on the news because the patent office sent his "maintenance" payment bill to Microsoft somehow instead of him, and now they wanted $2500 plus a $1600 late fee because he did't pay on time. What's the patent for? Wells, he's calls it a generator, and says once the battery starts it, the magnets in it makes enough power to keeps it running and supply more power, no more battery or other power source needed, and it can run your car or power a whole building in a blackout and hes just waiting for investors to back it.

Yessir, an electrical generator that needs a battery to start it, but then puts out power forever without any input or fuel. And he's actually GOT THE PATENT ON IT.

Dave, contact the man, you won't need that battery bank. And he's looking for investors.
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Re: Optimal propulsion system

I'm sorry but there is no such thing as free energy. Even if the oil companies did own such patents, there would be so much money to be made from this technology that oil would be the least of their reasons to suppress it. There will always be a need for oil even if an energy source to replace it was found. There will allways be a need for lubes, plastics, and yes fuel derived from fossil fuel. If the technology existed, someone would have produced it anyway. China and others certainly do not recognize US patent laws. Just having a patent on an idea does not mean that it can be used in a real life setting either. So yeah, we may have a breakthrough sometime in the future, but I wouldn't hold my breath waiting for it. I like the ideas some have put forth around sound and vibration dampening. A good muffler design makes a big difference too. Most marine diesels I have seen are very crude and vibrate much more than need be. A good balancer system with a big heavy flywheel will go a long way toward making these small diesels more enjoyable to live with.

Kevin

Quote:
Originally Posted by hellosailor View Post
Fortunately those patents that the oil companies bought, were taken out in the 1930's. Yes, the conspiracy goes that far back and the good news is, the patents are due to run out soon!

Heard about a man in Florida who got on the news because the patent office sent his "maintenance" payment bill to Microsoft somehow instead of him, and now they wanted $2500 plus a $1600 late fee because he did't pay on time. What's the patent for? Wells, he's calls it a generator, and says once the battery starts it, the magnets in it makes enough power to keeps it running and supply more power, no more battery or other power source needed, and it can run your car or power a whole building in a blackout and hes just waiting for investors to back it.

Yessir, an electrical generator that needs a battery to start it, but then puts out power forever without any input or fuel. And he's actually GOT THE PATENT ON IT.

Dave, contact the man, you won't need that battery bank. And he's looking for investors.
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  #30  
Old 09-11-2012
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Re: Optimal propulsion system

"no such thing as free energy'

Swede, the oil companies have been putting out that myth for a hundred years, but now here's this fella got himself in the news, he's actually GOT THE PATENT FOR IT!

So, it must be true. :-)
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