Sunday, August 11, 2013

Re: [Electric Boats] Re: Thunderstruck versus... well everyone else!

 

I would agree with all your conclusion and rules of thumb Mike but I think one point you make deserves special  emphasis.
 
"each boat is unique and each boater needs are different"
 
For sailboats, the choice of an electric auxilliary kinda boils down to one big consideration. Are you operating your vessel as a power boat with auxillary sails many people do nowadays or a truie SAILboat with auxillary power? This is a huge determining factor for what your system should be or even if you should go electric at all. Believe it or not, there are still some purist out there that don't even have auxillary motors on thier SAIL boat and there are even more that have them but refuse to use them except in the most extreme situations where they're  in danger of losing thier boat. A category of sailor I once counted myself as, in my youth, but have totally gotten over in my old age.
 
I think that if you've determined electric propulsion is actually the right choice for you, then sizing it is your next challenge. The Arc is a 20 ton vessel that we cruised over 250 miles in last winter using a 5 kW golf cart motor as our only means of propulsion and solar panels as our only source of fuel. And actually accomplished this under some pretty extreme conditions.  We did have a 40 hp diesel to fall back on in an emergency but managed to avoid using it by carefully planning our passages, waiting on the tides and weather to cooperate and admittedly, going a bit slow sometimes. But it worked, so it is possible, and we are plannng a 1500 mile cruise for this winter.
 
I would say the often quoted rule of thumb of 1 kW per ton is very good advice but as I frequently say, don't let your thumb get in the way of good design. Costs go up considerably with the size of your system and I can tell you from experience, you can get by with a lot less than 1 kW/ton if you want to. Although I would not recommend too much less than 1 kw/ton  if you don't have something backing it up for emergencies.
 
It all depends on what you want from your boat but if you're in a hurry, forget about a sailboat or electric drive and get something with a plaining hull and obscene horsepowered outboards or a trawler with twin turbo diesels. However when you get to the fuel pump, remember the old acronym for B.O.A.T. (Bring Out Another Thousand)
 
 
Carter
 

From: Mike Gunning <mike@electricyachtssocal.com>
To: electricboats@yahoogroups.com
Sent: Sunday, August 11, 2013 12:37 PM
Subject: [Electric Boats] Re: Thunderstruck versus... well everyone else!

Vendor Alert

I sell and support Elco, Electric Yacht and Torqeedo products along with batteries.  These companies build only marine products and are well versed with boat propulsion characteristics.
The industry does not have a standard way to describe their products.  Some are "equivalent HP" and some "kW in" vs. "kW out".  I know that this audience is focused on electric propulsion and many of the contributors are well versed and understand the differences but many others may not.  The EY 10.0 and Elco 2000 are both about 8.5 kW continuous output (20 plus minutes or so).
Here is a boat example: the Catalina 30 needs a 10kW input or 8.5kW output motor to really push it and anything less will make it difficult to avoid issues that may present themselves.  10kw in HP is 13.4.  In the electric world that will work because it is really HP to the shaft and that is likely equal to a diesel manufacturer's bench HP of about 20. But Catalina sold that boat over the years with motors from 1 to 4 cylinders and from 11hp to 30hp.  And do not forget the propeller is critical to motor performance.  They all pushed the boat but how well did they do it.  Sometimes they wanted to make a marketing price point!
It is very difficult to bundle batteries with motors as each boat is unique and each boater needs are different.  It is also difficult to bundle generators for the cruiser as each of us have our own unique needs. 
The rules of thumb after talking to well over a 1000 people over the last three years of doing my "retirement business" seem to be these:
If you use more than a gallon of fuel when you take your boat out, buy a diesel or hybrid.
Each knot of speed will just about double the amp (power) draw of the electric boat, therefore slow is much better and 70% of hull speed is just about right.
It seems that a battery pack that will give the boat about 15 to 20 mile range at 70% hull speed is just about the right size for most and will equal weight of the removed powerplant.
It's a sailboat and if you use it in the right order, electric will make your life on the water better.  So sail it and wait for tides, currents, and wind to go in your favor and do not try to overcome nature.
Mike Electric Yachts of Southern California
--- In electricboats@yahoogroups.com, oak <oak_box@...> wrote:
>
> Taking a quick peek at the web site, it looks like they have a very nice product.
> I have a couple of questions:
>  
> 1) Does the system price INCLUDE the batteries??  (kinda' sounds like it does, but there are no details)  If it does, what are the details on the batteries?  100AH AGM batteries?
>  
> 2) I also have a Catalina 30.   Can you get one of their systems that would fit the placement of where the shaft would need to be for a C-30, or does that have to be worked out by the owner?
>  
> 3) For protected waters, would the EP-1200 be sufficient, or would you really need to step up to the EP-2000 (for only another $1000, why not - especially if it included the batteries...)
> 
>
> ________________________________
>  From: "asailor0905@..." <asailor0905@...>
> To: electricboats@yahoogroups.com
> Sent: Friday, August 9, 2013 12:17 PM
> Subject: [Electric Boats] Re: Thunderstruck versus... well everyone else!
> 
> 
>   
> 
> Hello , Bob here 
> 
> I too am new to this technology, I have a Catalina 30, Ive seen the ELCO website and am strongly considering this product.
> Does anyone have comments regarding ELCO on this forum ?  Thunderstruck seems too "cheesy" and I do not want to mess with the
> mounting etc, rather spend time on the water , plug/play & go - any problems and I know who to call, same reason I wouldn't build my own laptop, 
>




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