Didn't know there was an electric thread going on. SUre, I'll post
my standard FAQ on this subject as follows:

My apologies to those of you who have heard it too many times
already. Skip to the next message.

For those who care, I have been doing this for a few years now, and
have designed installations for a couple of other boats, so feel free
to ask questions.

Best regards, Chris McKesson

Sundance's Electric Drive
FAQ

Describe the boat:

A 1968 COlumbia 36 with a family of three living aboard and cruising
full time on the Pacific Coast of USA.

Describe the system:

36 Volt DC electric drive. Consisting of:
One Advanced DC Model A 89 electric motor rated at about 4 kW
One Lester Electric Company 36 Volt battery charger rated at
25 Amps
One Curtis 1204 DC motor Controller
One bank of 36 Volt power, consisting of six Trojan T-105
6Volt golf cart batteries, each holding 220 Amp hours of "juice"

The system drives the yacht's original shaft and propeller, via the
previously-fitted Hurth HBW 50 gear box. I used the gear box because
it provided three key features: (1) existing shaft alignment, (2)
integrated thrust bearing, (3) convenient mechanical reverse.

The motor is rated at 3000 rpm. The gearbox is 2:1. The diesel
previously in the boat was a Farymann with a 3200 rpm red line, so
the system isn't far from the mechanical driveline. Note that there
is no need for the RPM reduction necessarily, with this type of
motor – it will produce full power at almost any RPM . The real
purpose of the gearbox, in my situation, was to provide a thrust
bearing.

How fast can you go?

About 5 knots, although we normally steam at about 2 or 3. After
all, if we're steaming it's because there's no wind.

At 5 knots the motor draws 150 Amps. We normally steam at 50 Amps,
which yields 2-3 knots. Note that we throttle by amperage, not by
RPM. In fact, we don't even have a tachometer on the system.

How far can you go?

Without running the generator we can go about four hours at about
three knots. (I've never tried it so I don't know for sure, that's
why all those "abouts" in that sentence.)

At two-three knots we run at a throttle setting of 50 Amps. If we
pull the whole 220 Ah out of the batteries then this works out – in
theory – to 4.4 hours running time. In reality we normally light the
generator at about half of that time.

With the generator running we can go much longer, maybe forever. The
longest we have ever run was to steam for about 10-12 hours off of
Point Reyes in a flat oily calm.

After about 10 hours of steaming at 50 Amps the controller shut down
due to overtemp. I have not installed a heat-sink / fan combination
yet, but this would be the obvious solution. This shut down causes
me a small concern since it happened in the cold waters off Point
Reyes – what will happen in Mexico? I should buy a heat sink and
fan, even if I don't install them soon.

What do you like best about the system?

1 SILENCE!
2 Very low maintenance:
a. Once a month top up the batteries with a nice non-toxic
chemical called: water.
b. Annually check or replace the motor brushes, and check the
motor bearings: $50
c. Every three to five years plan on replacing the batteries:
$400.
3 No piece of the system weighs more than 50 pounds.
4 All parts are commercial off the shelf
5 No start up procedure, no warm up procedure, no shut down
procedure. Turn the switch and go.
6 Refuel every time I'm in the slip. In coastal cruising mode
we use about 6 gallons of generator fuel a year. I'd be willing to
wager that even the lowest consumption diesel boat out there uses
more than that for propulsion.

What about weight?

My system is lighter than the diesel it replaced, not counting the
generator.

What about propeller matching?

Propeller matching is really no problem, because of the nature of a
DC motor. You see, with a DC motor the throttle controls power level
directly. With a diesel the throttle controls RPM, and you really
have no idea how much power you are putting out (Indeed it's my
belief that most boats use less than half their installed power, and
their owners never know it.)

With the DC drive on the other hand, I set the power level here at
the throttle, and the motor will spin up to whatever RPM is required
to get the prop to absorb that power.

OK, I admit I'm simplifying somewhat – you could in fact overprop or
underprop an electric drive, but the range of tolerance is MUCH wider
than with a diesel.

How much did it cost?

All up, about $1500, broken down as follows:
Motor $500
Charger $300
Batteries $400 (= 6 x $65)
Controller $200
Misc small parts $100

What would you like to change?

I'm still looking for ways to increase range, including increasing
range at high throttle.

Where did it all start?

When I was a wee lad living in Mexico on my father's California 32
PEGASO, I observed that we used a lot more electricity than we did
propulsion. Seemed like we ran the engine more to put power in the
batteries than we ran it to push the boat. So doesn't that tell me
that the installation is emphasizing the wrong thing? Maybe yacht
engine installations should emphasize electricity production, and
make propulsion secondary?

This is even more true today, in the face of the growth of on-board
electronics. I would not be surprised to see a true integrated
electric yacht appear on the market soon. And if anybody wants to
get ahead of the curve, have `em call me!

What are the limits of your system?

1) Battery capacity – think of this as my fuel tank. I have
about 220 AH of "fuel", good for about 4 – 6 hours of steaming at,
oh, about 3 knots.
2) Motor size – Limits my top speed. My 4 kW motor will get me
to about 5 knots in calm water.
3) Cooling – Add this to the "fuel capacity" column. If I run
for over eight hours, at say 50-75 Amps throttle, then things will
start to get hot and eventually the motor controller will shut down
to protect itself.
4) Generator – I can extend my range by running the generator.
Think of this as having a tanker right alongside, constantly topping
up my battery "fuel tank." But my generator fuel is limited, and
it's noisy, so I don't like to use it.

Why do you only find these on old boats?

Probably because we (the people who own such boats) are tightfisted
and willing to do the work ourselves, coupled with the idea that we
can't hardly lower the value of the boat any further, so why not?

There is nothing about the concept that wouldn't work on a gold-
plater. Indeed, I'd love to work with somebody to design such a
system. Remember, it's good enough for the QE-2 and the Navy's
billion-dollar destroyer, it ought to be good enough for your Cabo
Rico too.

Where did you get the pieces?

My system is made entirely from off-the-shelf electric car
components. Indeed, my system is almost entirely golf cart parts,
bought from Wilde EVolutions, over the Internet.



--- In columbiasailingyachts@yahoogroups.com, diplodocus@a... wrote:
> Chris, since you're back on the list, maybe you could explain to
all the guys
> who've been chattering about eletric propulsion without knowing
much on the
> subject, what you did with your boat's motive power.
> john
> pamperop iv
> > Steve is your engine rated at about 30-35 hp?
> >
> > If so, my congratulations because you have one of the few
sailboats
> > with the right propeller on it.
> >
> > By my calculations your engine is putting out about 9 hp at 2400
rpm
> > (from your fuel consumption figures. You burned 480 hp-hours of
fuel
> > in 51 hours, for an average output of around 9.5 hp.) And you
did
> > that at about 2400 rpm.
> >
> > Since a propeller's power demand varies as the cube of the rpm,
this
> > means that your propeller will require (let's see,...(3600/2400)
^3 x
> > 9.5 hp =) 32hp to turn at 3600 rpm. And, lo and behold, that
point
> > lies right on your engine's rating point.
> >
> > And THAT's unusual. Most sailboats are underpropped (or over-
> > engined, it depends on how you look at it.)
> >
> > Chris McKesson
> >
> > --- In columbiasailingyachts@yahoogroups.com, "Steven Gaber"
> > <sgaber@i...> wrote:
> > > Kip:
> > >
> > > Your engine is rated for constant running at 2300 RPM, and when
it
> > was new, could probably run at that speed all day without harm.
Wear
>
> > and deposits probably prevent it from doing so nowadays. Its
rated
> > horsepower will be produced at a higher RPM. Most older engines
> > could rarely produce their rated horsepower.
> > >
> > > Kind of like the Atomic 4, which is rated at 30 hp. If you
tried to
> > get 30 hp out of an Atomic 4, it would blow up before it ever got
> > there. A-4s deliver about 12 hp to the prop.
> > >
> > > Similarly, the Perkins "50 hp" Diesel could never produce 50
> > horsepower.
> > >
> > > But the newer Diesels are a different breed. They generally
run at
> > a much higher RPM and can actually deliver their rated horsepower
to
> > the shaft. The Beta Marine engines up to 37.5 hp (which has
about
> > the same power curve as the Perkins) all develop their rated
> > horsepowers at 3600 RPM and are designed for constant running at
3000
> > RPM. I rarely run mine above 2800 RPM and generally cruise at 24-
> > 2500. The temperature gauge has hardly ever moves past the first
> > notch on the dial.
> > >
>
> > > My engine now has 51 hours on the meter. I have an 18-gallon
tank
> > and have only filled it twice. The fuel gauge now reads 1/2
tank,
> > for a total fuel consumption of 27 gallons..That averages to
overall
> > fuel consumption of a little over 1/2 a gallon per hour.
> > >
> > > Anyway, it seems to me that if you need to limit your engine to
> > only 1400 RPM to prevent it from overheating, you still have a
heat
> > exchanger problem.
> > >
> > > Steve Gaber
> > > Sanderling, 1967 C-31 #77
> > > Oldsmar, FL
> > >
> > > ----- Original Message -----
> > > From: "Kip Hamilton" <kiphamilton@a...>
> > > To: "Columbiasailingyachts"
<columbiasailingyachts@yahoogroups.com>;
> > > "Columbia-List" <columbia-list@s...>
> > > Sent: Wednesday, July 30, 2003 4:46 PM
> > > Subject: CYOA - Albin diesel question
> > >
> > >
> > > > Hey guys.
> > > >
> > > > Now that we've solved the overheating problem with the new
heat
> > > > exchanger, I have a question.
> > > >
> > > > At what ROMs do you usually run your engine?
> > > >
> > > > Lets say,
> > > >
>
> > > > 1) What is your normal cruise RPM? Fuel usage in GHZ?
> > > > 2) What is your "econocruise" RPM? Fuel usage in GPH?
> > > > 3) What is the max RPM you've run for any length of
time?
> > > >
> > > > I'm just curious because the manual we have says the little
puppy
> > is
> > > > rated for a constant 2300, but we've never been able to go
much
> > above
> > > > 13-1400 for fear of heating her up, so I don't know what
> > is "normal".
> > > >
> > > > After all we have been through, I sure wouldn't want to blow
her
> > up at
> > > > this point.
> > > >
> > > > THAT would be cause to jump for sure.(I have had the bridge
> > selected for
> > > > a few years now)
> > > >
> > > > Thanks!
> > > >
> > > > Kip (& Beth)
> > > > "MoonBreeze"
> > > > C36 # 326
> > > > Severna Park, MD
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> >
> >
> >
> > Columbia Yacht Owners Association:
> >
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