[Public-list] weight distribution and electric power

[J Bergquist]

Yeah well nobody knows this because none of us have tried it. But it looks
like we will find out from Dan.

My 2 blade prop windmills just fine without aligning with the keel. I have
to put the engine in reverse to hold the prop in place.

But I believe you are correct that there would be prop implications to
ensure efficient turbine operation. It's probably more complicated than just
2 vs. 3 blade though. But if he's replacing the whole engine, the prop is
probably gonna go too, don't you think?

At least, that's what I did...new prop, new shaft, new cutless bearing,
dripless packing. If you're going in there and doing the job, you might as
well do it right. Do it right, do it once, and be done with it.

J

On 9/29/06, John Boor <mahseer at kos.net> wrote:
>
> If regenerative braking is considered the prop would have to be replaced
> with a 3 blade since the standard 2 blade would align with the keel and
> provide no rotation.  Even a 3 blade would produce drag and I am not sure
> how much torque would be needed to generate power.
>
> John Boor
> MAHSEER #380
>
> > I have no idea how Dan is planning to recharge while sailing, but solar
> > panels are not the only way to do this. 2 other examples are wind
> > generation
> > and water turbine generation.
> >
> > Water turbine generation was used by Gelinas during his round the world
> > cruise. It basically uses a propeller as a turbine, connected to a shaft
> > which drives a generator. Since a motor and a generator are physically
> the
> > same thing, most electric motors can be used as generators, and in fact,
> > most electric launches are set up in exactly this way.
> >
> > Regenerative braking in hybrid cars works exactly the same way. This
> > technology is well established and frankly much older and more mature
> than
> > photovoltaic solar power.
> >
> > I don't know much about efficiency numbers, but if Dan figures he's
> > motoring
> > for 15 minutes to a half hour to get out of the harbor, followed by
> > several
> > hours of sailing, I am guessing that since the generator is running at
> > least
> > 10 times longer than the motor (assuming 2.5 hours of sailing for every
> 15
> > minutes of motoring), he probably is not going to have a problem
> replacing
> > whatever juice he took out.
> >
> > Plus he'll have a sweet way to recharge his house batteries and replace
> > the
> > juice taken out by his lights and refrigeration and electronics and
> > whatever
> > else.
> >
> > I wouldn't use the system while racing, though...that pesky 2nd law...no
> > free lunches and all that.
> >
> > JB
> >
> > On 9/29/06, John Boor <mahseer at kos.net> wrote:
> >>
> >> > yes john, no gasoline.
> >> >   i was told i can motor 25 to 50 mile before empty. supposedly th
> >> batts
> >> > will recharge as i sail. the system has "smart" chargers that i am to
> >> > plug in while at the dock. i wont know until next springs sea trials
> >> how
> >> > well any of this works.
> >>
> >> Dan
> >>
> >> I am looking in to solar panels to recharge my house batteries(4x
> 225Ahr
> >> 6volt batteries) my concern is that 2 80watt panels at about 30x48in
> >> each
> >> will just keep my batteries charged when I use my refridgeration
> >> (2.5Amps
> >> per hour) this is with full sun (no shadows on the panels)all day. With
> >> your 48 volt system and limited sun hours I cannot see your bateries
> >> beind
> >> charged very much while sailing. I hope you have resolved this problem.
> >>
> >> John Boor
> >> MAHSEER #380
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