T-Pain Is On A Boat: Re: [Electric Boats] Propulsion Marine 5 KW Electric Drive

James , my current boat is a beautiful sail boat , with a very good diesel in it.

I love using her under sail , we fish from her under sail , a task she isn't made for.

But I'm not ashamed to fire up that diesel , and make good use of it , when appropriate.

But , I'm going to get a new boat built , one I can fish under sail from easier , and yes , like you suggest , motor sailing with a little e-power would be perfect .

While the hybrid system I am contemplating does have a regen capability , and we would use some solar panels , the chief generator will be the hybrid system , which generates 110A at 56.6 volts.

Its maximum consumption of the electric motor is 200A/56.6 volts , but light work , motor sailing , it should draw much less .

I would see us taking the tender out to her on her swing mooring , doing an engine check , starting her up , and by the time we are set to go , the engine would be warm .

Motor out of the harbour , shaking out the sails , then once under sail , shut down the diesel , unless the batteries are down .

Then , use a little e-power when needed while sailing , all day , allowing enough diesel motoring time at the end of the day to recharge the batteries.

Take her back to her swing mooring with batteries fully charged , for the next day.
The boat I am contemplating is a traditional , easily driven Norwegian canoe stern fishing boat of 28 ft , a beauty to my eyes , and I believe if it is built to accomodate hybrid power , in particular the batteries , then it would be truelly great to use , for fishing under (e-power) sail , it would be very appropriate , something my current boat is not .

Regards Rob J.

From: James Lambden <james@toolboat.com>
To: electricboats@yahoogroups.com
Sent: Thu, 28 October, 2010 3:19:07 AM
Subject: Re: [Electric Boats] Propulsion Marine 5 KW Electric Drive

Tom,

I haven't done tests that compare a bucket dragged to a propeller. The analogy came from on old salt and I believe it. Especially if the propeller has a lot of blade area.

What we do know is add a folding or feathering prop to your boat and you will add a knot to performance on average. It is hard to measure the performance of adding power to the propeller but I estimate that it takes about 75 watts to eliminate the propeller drag, thus adding 1 knot in boat speed, and another 125 knots will add a second knot to boat speed.

Motor sailing on an electric boat is definitely the sweet spot of this technology.

When I switched to the new propeller I found that I have more thrust at 700 propeller rpm with the 12.5 x 14 than I did with the 12 x6 at 2,000 rpm. What a difference.

Also, by slowing the whole system down, we eliminated most of the gear noise. We like it quiet on Kapowai!

We spend as much time testing as possible and will be posting results on a new website in the next couple of days. I will let the group know the link as soon as it is ready.

James

On Oct 26, 2010, at 10:49 PM, Tom wrote:

Hi James,

Have you conducted drag tests comparing a given diameter prop with a corresponding diameter bucket? That sound like something I'd like to try (unless you have already done it).

Can you give us a comparison of power regenerated when using the two props you mentioned?

Thanks!
-Tom

--- In electricboats@yahoogroups.com, James Lambden <james@...> wrote:
>
> When you have an electric boat you have to make a decision whether or
> not you want to be hooked into nature's energy.
>
> Having a big prop does exactly that. A big propeller turning slowly
> adds enormously to the efficiency of the system, perhaps twice as
> much in the case of Kapowai going from a 12x 6 to a 12.5 x 14.
>
> A big prop also increases regeneration. Regeneration is directly
> proportional to size and shape of the propeller.
>
> However, it does come at a cost, and that cost is sailing speed with
> the propeller not turning. It will slow the boat down as much as a
> bucket dragged behind the boat of the same diameter.
>
> With Kapowai, we have a 20 KWH battery bank so it could run at zero
> thrust for over 200 hours. Ultra-efficient drives, have very low
> phantom loads, making this possible.
>
> One 200 watt solar panel aimed at the sun would more than compensate
> for the energy required to zero-thrust the propeller over a 24 hour
> period.
>
> An additional 200 watt solar panel, aimed at the sun, could add an
> additional 1 knot of boat speed over a 24 hour period.
>
> James
>
>
>
> On Oct 26, 2010, at 7:16 PM, Rob Johnson wrote:
>
> >
> > JC , I would have to answer YES to both questions , thus I believe
> > having the e-motor on , under sail , would be a big advantage.
> > Regards Rob J.
> >
> > From: Joao Carlos d'Almeida <joaocarlosdalmeida@...>
> > To: electricboats@yahoogroups.com
> > Sent: Wed, 27 October, 2010 12:05:54 PM
> > Subject: Re: [Electric Boats] Propulsion Marine 5 KW Electric Drive
> >
> >
> >
> > Does a larger prop create more drag when the e motor is not on? And
> > will this slow down a sailboat very much?
> >
> > JC
> >
> > On 26 October 2010 16:33, Rob Johnson <dopeydriver@...>
> > wrote:
> >
> >
> > Yes , so I thought.
> > I've used the diesel on my boat to motor sail , and while it allows
> > me to gain a couple of knots , and point a little higher low revs
> > for a long period of time is not good for the diesel .
> > But should be ideal for the electric motor , I believe.
> > I've just this minute got the pricing though on a hybrid setup ,
> > the price has doubled , over the diesel alone.
> > I guess I'll wait , its sure to come down.
> > Regards Rob J.
> >
> > From: Daniel Michaels <nov32394@...>
> > To: electricboats@yahoogroups.com
> > Sent: Wed, 27 October, 2010 10:00:07 AM
> >
> > Subject: Re: [Electric Boats] Propulsion Marine 5 KW Electric Drive
> >
> >
> >
> > It will usually make sense to use the electric drive while sailing.
> > It takes very little power.
> >
> > Dan
> >
> > --- On Tue, 10/26/10, Rob Johnson <dopeydriver@...> wrote:
> >
> > From: Rob Johnson <dopeydriver@...>
> > Subject: Re: [Electric Boats] Propulsion Marine 5 KW Electric Drive
> > To: electricboats@yahoogroups.com
> > Date: Tuesday, October 26, 2010, 4:10 PM
> >
> >
> >
> > Just to go off on a tangent slightly.
> > Assuming we have a motor sailer with a hybrid diesel of 50hp
> > diesel , and 10hp electric .
> > Under sail , wouldn't we get maximum value from the electric
> > motor , turning the large prop ?.
> > The motor isn't so much driving the whole show , as contributing ,
> > and instead of there being prop drag , there is prop drive .
> > What I envisage is an electric drive contribution for most sailing
> > time .
> > Does this make sense ?.
> > Rob J.
> >
> > From: James Lambden <james@...>
> > To: electricboats@yahoogroups.com
> > Sent: Wed, 27 October, 2010 6:49:02 AM
> > Subject: Re: [Electric Boats] Propulsion Marine 5 KW Electric Drive
> >
> >
> >
> > Dick,
> >
> > That would be true. More propeller area means less propeller
> > slip and higher efficiency.
> >
> > However, you can accomplish the same thing by having a larger
> > propeller turning slower. ( A larger propeller will require a
> > higher reduction gear ratio )
> >
> > James
> >
> >
> >
> >
> > On Oct 19, 2010, at 10:34 AM, Dick B. wrote:
> >
> >>
> >>
> >> Jim:
> >> You said:
> >> < < However, as an electric drive consumes more power, the
> >> thrust per kilowatt decreases. This is because the propeller gets
> >> less efficient the faster it turns, which is a result of more
> >> propeller slip. Also, the electric motor becomes less efficient as
> >> it creates more power.>>
> >>
> >> This would indicate that a more efficient electric drive system
> >> to power a boat would be to have several motors running at a
> >> fraction of their max output driving several peopellers turning at
> >> slower speed. Is this true?
> >>
> >> Dick
> >>
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
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