Sorry to the originator of the thought and "Meander". I started it by using my experience and a personal example to explain what I thought was correct. Did not mean to hijack it. Hope the originator got the answers. If not, I hope he or she will ask and share more. Sorry again.
Dan
----- Original Message -----Sent: Friday, May 30, 2014 7:25 AMSubject: Re: [Electric Boats] 50 HP diesel VS electric
I too have been confused about this thread so went back to the source. It maybe that the confusion comes because the original thread was 'stolen'.
The original post concerned powering a 42' sailboat and now we are talking about a 4800# small tug.
I'm in one sailing group where stealing a thread is common practice but they don't discuss much of anything anyway.
Please don't perceive this as a rant, it just came about out of the confused state of an old man:).
eric SV Meander
---In electricboats@yahoogroups.com, <matwete@...> wrote :
At 75% power you'd be using 15 kw and 500# of lead acid at that rate would only give you 1/2 hour of cruising. Maybe I'm missing a detail?Sent from my Verizon Wireless 4G LTE smartphone
-------- Original message --------From: "'Dan Hennis' dhennis@... [electricboats]"Date:05/29/2014 5:20 PM (GMT-08:00)To: electricboats@yahoogroups.comSubject: Re: [Electric Boats] 50 HP diesel VS electric
I had though to replace the 30 HP Diesel with 20 Kw of 3-phase motor. I estimate from the plans, the associated tanks, hardware to be about 450-500#. The motor & controller vs. Diesel ICE, is a close swap and maybe a bit lighter. So I expect to comp out for approx. 500# in the highest amp Hr batteries my retirement can afford. If there is a void between the max amps used, and the 6-8 hours at 75% power, I thought to pack a little 3500 watt Honda or equal, with a reconfigured gen-head, to output DC directly to the cell pack.Field of dreams right? If I build it it will work? ;-)As for the projected thrust, never thought about it. Glen and Ken say 30 is the max suggested, and the hull speed is projected to be 6 kts. I have a theory that it will do exactly what they designed, and probably fully loaded towing a load too. But I am just blowin smoke and my experience with Glen-L plans is that they are spot on or even a slight bit conservative to be safe. Trust me, when it is finished, I will return with a report.Dan----- Original Message -----Sent: Thursday, May 29, 2014 6:34 AMSubject: Re: [Electric Boats] 50 HP diesel VS electricDepends upon the intended usage of this 4800 lb TUG, correct ? What is the desired max THRUST ? for How Long ?
What type of Battery Bank ?-----Original Message-----
From: James Sizemore james@... [electricboats] <electricboats@yahoogroups.com>
To: electricboats <electricboats@yahoogroups.com>
Sent: Wed, May 28, 2014 9:16 pm
Subject: Re: [Electric Boats] 50 HP diesel VS electric
That would be 2.4 tons. And a motor boat so the minimum continuous HP should be at least 6.4 or rounded up 7HP.
On May 28, 2014, at 8:41 AM, "'Dan Hennis' dhennis@... [electricboats]" <electricboats@yahoogroups.com> wrote:I am planning to start my build soon, and it is a 4800# tug that recommends 10-30 HP.Dan----- Original Message -----Sent: Wednesday, May 28, 2014 12:45 AMSubject: Re: [Electric Boats] 50 HP diesel VS electric
For a sailboat 1000 watts per ton of displacement. 2000 watts per ton for a power boat.My boat has a 13 ton displacement and is a powerboat so I should have around 26 continuous HP.
On May 28, 2014, at 12:40 AM, "Hannu Venermo gcode.fi@... [electricboats]" <electricboats@yahoogroups.com> wrote:You probably need about 1/3, or about 17 Hp from a continuous duty
electric drive.
If you could put a prop 2 sizes larger on it, you would also get it to
be more efficient, and have a lot more thrust.
Historically, ICE solutions are pretty inefficient.
So, they just spin the prop faster, loosing efficiency, while increasing
thrust.
Efficiency has not been an important factor in ICE boats, in the past.
Neither is it today, as a matter of fact.
Buyers want large, round, bathtub shaped hulls, and as much "space" and
glitter and "brand-name" yachty stuff as possible.
Succesful boatbuilders deliver what the customers want to buy.
Fwiw, 100 Hp in ICE, is far more than needed for a 24 m, 70 metric tons,
full displacement steel yacht a friend has.
He cannot be bothered to pay for a better prop (expensive), as a single
tank of diesel lasts all summer.
That boat uses about 20-30% of max power (but its lakes).
Maybe 30 days overnight use per summer, with 2 rooms and a sauna.
On 27/05/2014 23:06, 'Dan Hennis' dhennis@... [electricboats]
wrote:
> I am looking in DIY,
> and if I install an electric motor I'd rather have a motor for all
> situations right away(coastal and blue water)
> what I dont know is what size electric motor would do the same job as
> my 50 hp diesel?
>
> Martin
--
-hanermo (cnc designs)No virus found in this message.
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Dan Hennis
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Dan Hennis
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Respectfully,
Dan Hennis
;-)>
Dan Hennis
;-)>
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