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Need e-motor for 40ft boat


buehnerjl
 

All,<br><br>I would like to take out my old
diesel 4-154 (53hp) engine and install an electric
motor. The boat weighs 14 tons and I will be removing a
60 gallon fuel tank and a very heavy engine. The
problem is that I do not know where to start the process.
How do I find out what components I need for the
electric system, or what should the system even look like?
Any help or leads on where to start would be greatly
appreciated. Additionally, I am currently earning an MBA from
Johns Hopkins University. I think there are two major
reasons that the electric industry has not exploded.
First the boating industry in general does a poor job
of marketing products to the general consumer. If
car manufacturers waited for consumers to come to
them, they would be bankrupt. Second, and this is more
of a question, is the electric motor industry
attempting to generate business to business contacts
regarding electric boating possibilities? Would consumers
buy electric motors installed in new boats. Also,
what is being done to market electric drives as
replacements for older engines? I believe the electric boating
industry can increase its market share if it can convince
consumers to replace their old, worn-out, or dead engines
with electric drives. <br><br>Thanks,<br>James


kirsti_drewsen
 

Welcome, welcome!<br>Read old messages, and
you'll see that I'm fumb'lin' in the dark also.<br>The
good people in this club have pointed me in various
directions, to interesting sites.<br>...The more I learn, the
more I realize how ignorant I am....<br>It's exciting,
learning, I mean!<br>Some day I WILL have an electric motor
in my boat...All I have to do now is to find out if
it should be the $12.000,- model, or the
$3.500,-...<br>Flipping a coin maybe?<br>Good luck, and I hope you'll dig
up some good info.<br>Kirsti.


p4w_jf
 

James,<br><br>I may have some experiences to
share. I have embarked on a similar quest three years
ago after the diesel on my 29 Ft Cal failed. Not
wanting to settle for a replacement diesel, I began
looking for an electric solution. <br><br>In the process
I have needed to and continue to learn alot, an
have organized the journey into what is titled "The
P4W Project" (Power Forward Project). The mission of
the project is to test electric propulsion
technologies, measure public reation and promote the use of new
energy technologies.<br><br>After evaluating a few DC
motors, such as series wound traction and pluse width
modulated DC motors, we selected the pluse width modulated
motor. Last March we launched and are begining to test
components that make up electric propulsion systems. The Cal
is scheduled to be on tour this summer.<br><br>The
P4W Project has been invited to exhibit at an Earth
Day Event, April 26, sponsored by the US Department
of Justice. Additional details are available via my
email at p4w@... <br><br>I to am attending JHU's
MBA program.<br><br>I'll be glad to help.<br><br>John


buehnerjl
 

Kirsti,<br><br>Thanks for the welcome. It makes
me happy to know there are people in the world
willing to help. I was wondering if you could give me a
run down on some of the decisions you have made for
your boat so far. What are the options you are
considering and what are their benefits/downfalls. Your
opinion is important to me. I also have decided I will
definitely go the route of electric. I read the article by
Russell O'Connell in the EBAA section of the Feb 2000 EV
News and was inspired. <br><br>Thanks,<br>James


cedarcroft
 

Where to start? For what it's worth, here how I
would go about it. <br><br>In order to get something
like the same horsepower as your current diesel you
will probably need a motor in the 12-15hp range. My
KTA (with whom I have no relationship, by the way,
other than being a happy customer) catalog lists two in
that range, both under $1000. Ken Koch at KTA was very
good about working with me, once I specified what I
thought I needed, in detailing out the rest of the system
and giving me a quote on the package and a very
detailed wiring diagram. He doesn't know about boats,
however, so you will have to bring your own knowledge of
your boat and your needs to the discussion<br><br>The
next big question is battery capacity. Let's say the
motor is wired for 72V. At 72V each hp will require
about 10.4A. If your normal cruising speed in this boat
requires 8hp (i.e., about 32 of those inefficient internal
combustion horses), then you will need 8X10.4 amps for each
hour of powering between charges: 83.2
amp-hours<br><br>I use Group GC2 batteries in my boat. They are 6V
245 AH and weigh 66 lbs. If you wire 12 of them
together to create a 72V battery bank, you will have 792
lbs of batteries. (You are right to be considering
the trim of the boat when you remove the tanks and
your heavy diesel. Nowadays even repowering with a new
diesel often requires adding lead ballast to a boat in
order to get the boat back down on her lines, due to
the lighter weight construction of modern diesels.)
You will also now have a 72V battery bank of 245AH.
<br><br>As a rule of thumb, you never want to draw your
battery bank down below about 80% of its rated capacity.
That means your battery bank has an effective limit of
about 200AH. At your cruising speed of 83.2A, it means
your range with this bank is about 2.5 hrs between
charges. If your boat cruises at 7kts with this power,
your range is 16.8 nautical miles.<br><br>For many
sailors who use their engines just for getting in and out
of the harbor, this would be ok. For others, it
would not. There are various means of increasing the
range, some very expensive, technical and sophisticated,
others much more plebeian. I'll stick to the
plebeian.<br><br>Higher rated batteries are one choice. Group L-16's are
rated in my catalog at 350 AH, a 43% increase in
capacity. (Because they are somewhat more specialized the
L-16's are not as cost effective as the GC2's. If you
shop you should be able to get the GC2's for around
$60 ea.; the L-16's would probably run closer to
$150.) Increasing the voltage of the system and/or the
number of the batteries is obviously another choice.
Doubling the size of the bank and using L-16's would give
you a theoretical range of about 50 mi. between
charges. It would also give you 2, 832 lbs of batteries.
At some point you confront the fact that a 14 ton
boat is one big boat and if you couple that with a
demand to go fast or far, you have defined an expensive
system. Or maybe even one that doesn't yet
exist.<br><br>Anyway, that's an illustration of some of the variables
to play with and how you might take the first steps
in envisioning what a system for your boat might
look like. BTW, Douglas Little's book "Electric
Boats", lays out many of these calculations and explains
how these systems work for the non-technical amongst
us, although his focus and experience is clearly with
smaller boats.<br><br>At some point there's a leap of
faith. Until the system is installed in your own hull
you really can only make a best guess at the exact
performance. As it turns out, for my 20' LWL, 1700 lbs launch,
I need about 1 hp to reach optimum cruising speed
and with my 245AH battery bank my range is about 45
mi.<br><br>Larry


buehnerjl
 

Larry,<br><br>This is great info, thanks!! the
theoretical hull speed of my boat is about 7 knots and the
boat weighs 14 tons. I am looking at about two hours
of motor time between charges. I will take your
advice, get the little book, then look at the batteries.
I imagine the system I want includes a wind
generator and a couple of solar panels. As soon as I figure
out my base requirements for batteries and motor (and
how the heck to hook the whole thing to turn the
prop) I will start focusing on other aspects. I am
currently hooked into shore power daily, but would like to
design a system that can recharge itself at
sea.<br><br>Again, thanks for your help.<br><br>James


ewhel
 

If you want to go electric..take fossil fuel HP
in boat and divide by 4 for electric equivalent. If
you want regenerative feedback from prop the most
will come from a brushless DC magnet motor and you
should consider changing the prop to the biggest 3 blade
you can fit into the aperture of the boat. In
brushless DC motors, and assuming an efficient prop, you
will need approximately 50 foot pounds of torque which
will relate to full speed in worst conditions
(1amp=1ft.pound over 120-144 VDC and 50 amp hours at max). This
will be much less in becalmed conditions. My 10 ton
Casey does 5 1/4 knotts on 25 amps in calm and 35 amps
working against a 22 knott head wind. Regenerative
feedback on brushless DC will allow you to have a 3 or 4
to 1 recharge ratio (for every hour on motoring you
must sail for 3 or 4 to put energy back) in light
sailing wind of 10 knotts. This can be as little as 2 to
1 in heavy air. <br> For continuous off shore use I
recomend a FischerPanda AGT DC generator in combination
with a smaller battery pack. For your application 150
amp hours (2 1/2 hours motoring on batteries) and a
6kw AGT will give you unlimited motoring with 3 to 4
times the fuel economy of the standard diesel. This
does not include additoional saivings from
regenerative sailing which, given the right wind conditions,
will carry you 80% of the time.<br> Look for a motor
that is sealed, inverter duty, continuous duty,with
thrust bearings and marinized. ewhel@....
(301)274-4479


budmorevoltsplease
 

That Casey of yours, does the silence of the
propulsion system attract comments? Must be a blast to motor
by the fuel dock without stopping.<br>It would
appear the The only fossils on your bay are in the
sand.<br>Happy boating,<br>bud


ewhel
 

budmorevolts...you have no idea!!! Picture
this..the Solo 6 in the Casey can stop the boat from 5 1/4
knotts in 20 feet!!! Now you are comming in to the fuel
dock, for ice and beer of course, and running at hull
speed...the dock attendant is watchin' this antique tank
rollin in at full speed and then suddenly...with no
noise...it just stops ! I have seen eyes as big as tennis
balls and would really like to have checked the guys
blood pressure. Then he walks around to the stern and
sees a big wooden plug in the exhaust pipe...Ohhh..the
pleasures of electric boating.