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Bob,<br><br>If an outboard on the Irwin 28 will
meet your needs and price is the determining factor,
then I doubt an electric is in your future.
<br><br>The attractions of the electric setup are:<br><br>1.
Silence<br>2. Extremely low operating cost<br>3. Longevity of
the system/low maintenance<br>4. Cleanliness,
environmental and otherwise<br>5. Efficiency<br><br>The
outboard cannot compete on any of these grounds with an
electric or even with a diesel. But where initial cost is
the major consideration, the outboard will probably
win out in this size range. The electric (unless it
is loaded with high-tech features) should be about
2/3 or 3/4 the cost of a replacement diesel and be
far cheaper to operate.<br><br>Larry

Somewhere in my future I hope to either build or
convert a 20 - 25 foot electrically driven craft.<br>From
the technical discussions in this club - I have come
to the conclusion that I am in the minority. I see
the technology as a means to an end rather than the
central point of electric boating. Yes I know we are a
very small market - but I think a major limiting
factor is that there are a lot of people like me who do
not want to get deeply involved in all sorts of
formulazations and yet are not willing to pay the rather steep
prices established by many commercial entities marketing
"packages". It would seem to me that for a 24' displacement
hull there could be rather easily developed two three
or four "systems" of propeller, motor, batteries,
charger, controls, and related materials. The same for
various sized sailboats. Until this becomes a lot simpler
- I think many folks will just go down to the old
store and purchase the latest gas or diesel replacement
engine. Am I missing something? Paul

Hi...I just bought an Irwin 28 with a dead Volvo
and am researching replacing it with an electric set
up. Cost is a factor so a "real world" installation
would be preferred ( after all I can always put an
outboard on the transom for $1000 or so) Any
suggestions/tips welcome.<br><br>Bob

James,<br> I am just now catching up on some of
the posts regarding your delema about "securing the
motor". Both Chris and Larry have offered good
suggestions here is another. If I were doing a large boat
like yours I would have my local macine ship take a
piece of round stock and weld an adapter flange to it
to bolt to my existing shaft. Then I would have him
turn down all but the last 1/2 inch of the shaft,
closest to the flange to 1 1/2". This would provide a
step which would prevent the saft from slipping in the
forward direction. (This is where you will be using it
the most. I don't think you will be doing too mush
reversing). Next I would buy a "double row sperical roller
pillow block bearing". Several manufacturers make them.
I checked my "Browning" book and found that a
series 1100 bearing will take 16,600 lbs of force
(combined thrust and radial loading). Make sure that the
shaft is long enough to attach a drive pulley on the
end opposite the flange I would put either a V belt
or timing belt to get the proper ratio between the
motor and the shaft as Larry suggested. Again as Larry
suggested you can get these bearing from "Applied Motion
Ind." or "Kaman" or any good Power transmission
house.<br><br>Hope that this helps. <br><br>Regards and happy, quite
motoring<br><br>Don

James -<br><br>I could also send you a
"schematic"ketch for drive train setup, but better yet, I'll send
you some digital images of the set-up when we finish
installing in our electric launch. May be a couple weeks,
but but I'm very busy with other deadlines at the
moment.<br><br>Regarding "how much torque can an electric motor take?. The
torque developed by an electric motor depens upon the
motor. For a given voltage, as you increase amperage,
torque increases (how linear this is depends upon the
motor). Get the power/torque/efficiency curves for the
motor you intend to purchase. It's really not a matter
of the prop overloading the motor per se because you
could limit the current to the motor via a pwm
controller or even a simple variable resistor controller,
and keep tabs on it with your ammeter. It is possible
your prop is too large in diameter and/or steeply
pitched such that you could fry your motor due to
excessive current draw and overheating, or conversely, your
prop is too small and your boat won't hit target speed
and your motor draws less than maximum rated current
even with the throttle wide open.<br><br>Chris
Krumm<br>krumly@...

Send me a private message, James, off-list with
your snail mail address and I can send you a diagram.
My email is in my profile. Afraid I'm not up to
computerized drawing. In fact, it may be the general consensus
that I'm not much on any kind of drawing, but I'll
give it a try.<br><br>I recently had an article
published about "Amber" in The Ash Breeze, journal of the
Traditional Small Craft Association, in which I tried to lay
out costs, performance figures, etc. I don't know
who's doing the book on bigger vessels. Boatbuilding
books are a pretty small niche market in the first
place and electric propulsion, I fear , would be even
smaller.It would be very tough to make it
profitable.<br><br>Larry

Chris and Larry,<br><br>I know this is asking
alot, but is it possible for you to draw a sketch of
your ideas and post it or send it to me at
buehnerjl@.... This may help me to understand the small
differences in how the pillow block or other itmes are
secured on the prop shaft. Additionally, Does anyone know
how much total torque an electric motor can take? My
concern is the size of the prop versus the torque that
the motor can handle. Where do I find or how do I
calculate this info? I will be buying the handbook of props
this weekend, does it give this kind of
stuff?<br><br>Thanks,<br>James<br><br>PS People have been asking what I am going to do for
a new engine. When I tell them electric they
suddenly look surprised, and inquire how. I have been
selling tens of people on electric in the last couple of
weeks. I think we're onto something. Who is putting all
of this new info into a book? What about a new book
for larger vessels?<br><br>JB

Just a note for anyone else out there who may
want it and for those who presently have the Excel
spread sheet that I devised. I have no commercial
interest in this tool. I developed it for my own use and
am willing to share it in the hopes that other may
find it useful. All of the formulas are stright out of
either "Doug Little book" or from "Dave Gerr's Book"
with the exception for a few which can be found in any
engineers hand book. <br> I password protected the sheet
only to keep anyone not profecient with excel from
entering data in the wrong places and to simplify
usage.<br> Once again if anyone wants it simply e-mail me
and I'll send it along. I'f anyone is using it and
can reccomend ways that it might be modified to make
it more useful please fell free to e-mail me you
comments.<br><br>Best regards and happy, quite motoring<br><br>Don
Baer<br>donaldbaer@...

Larry and James -<br><br>I have worked on 3
electric boats with inboard drives, set up for 24V per
local regatta rules. All boats used set screws w/
keyways on the prop shaft and radial pillow blocks. I've
always been concerned about shaft slippage or shearing
the set screws - there isn't much x-sectional area on
the set screw, even accounting for steel's shear
strength. The 20'launch I'm building now with high school
kids will use shaft collars on either side of a
spherical thrust bearing pillow block. The shaft collars
will be drilled and pinned through the prop shaft.
Bronze pins are in double shear in this case - can match
bronze shear yield to x-sectional area of pin x2, and
I'll use a safety factor of 2x in addition. May sound
like overkill, but this boat will run at 48V and the
motor will develop over 4 HP.<br><br>My local bearing
house said they typically look at thrust loads for
radial pillow blocks as 1/2 of rated rated radial load.
I've not found any literature ffrom Fafnir or Browning
to verify this, so I'm not sure I believe it. Hence
the use of dual row angular contact bearings to be
sure the thrust loads are accounted
for...<br><br>Chris Krumm

James, It was Donldbaer who offered an Excel
sheet which calculates loads and sizes. I have it -
seems quite good, but best you get it from him as he
went to the trouble to write and password protect it -
from memory somewhere around message 200. Cheers, Ted

I obtained my pillow block from a local
shop--Applied Industrial Technologies. You can find such places
in the Yellow Pages under "Bearings".<br><br>BTW, I
failed to mention but Gary's post makes relevant, that
the pillow block I used has two set screws which are
tightened down against reciprocal flats in the shaft to
make sure that it cannot creep forward under pressure
from the prop.<br><br>" Does<br> anyone have a rule of
thumb regarding prop size to thrust and overall<br>
speed?"<br>There was a discussion earlier on this list about how
to calculate/estimate this.<br><br>Larry

Larry and gary,<br><br>Thanks for the suggestion
for securing the engine and prop shaft. Where can I
find the equipment, pillowblock and marine thrust?
When I finally get an ida of the set-up and the
prices/products available, I will post it here. I also need to
figure out what size prop I am going to use. It almost
seems that bigger is better when it comes to the prop.
The boat is in the water, and I will pull it in
August. Until then I need to theorize. Does anyone have a
rule of thumb regarding prop size to thrust and
overall speed? Any suggestions on books explaining speed,
thrust, and the size of the boat?<br><br>James

You can buy proper marine thrust bearings as they
are required for flexible mounted diesels. or use the
pillow block idea but fit some kind of clamp to the
shaft to prevent the shaft pushing thru the
bearing.with this kind of setup there sould be no thrust taken
on the motor thus making motor installation fairly
straight forward.Props are usually mounted on a tapered
end on the shaft and pinned.Your best bet is to go
and have a look at some marine books at your local
libary the diagrams will give you a good idea of what is
required especially if you can find a book on converting
car engines for marine uses they tend to show the
various options for drive trains and are aimed at
diy.Goodluck ps.if you dont have any luck leave a message and
Ill try an dig up some articles I have somewhere and
scan and email them.

James,<br><br>These are great questionsIm kind
of surprised to realize how recently I was asking
myself exactly the same ones!<br><br>Motor to prop
shaft: there are a number of different ways to do it and
youll likely get other suggestions from this group. The
way I chose in the end was simple and has worked to
my complete satisfaction. I use a single V-belt
(some people use doubles) with a pulley or wheel on the
motor and another on the shaft. The difference in
circumference between the two determines your reduction. Im
running a 3.5" dia. on the motor and 8.25 on the shaft.
You can swap out the pulleys to get the most
efficient ratios once youre ready for sea trials. My local
place at least was very good about just letting me
exchange till I got about what I thought was right. One
unanticipated limitation was to be aware of how much clearance
you have for the larger pulley between drive shaft
and hull, floor or sole.<br><br>Some people in this
group like the cog belts under the theory that they are
more secure and have no slip. I went with the simple
V-belt because I had a chance for a trip in a boat with
a cogged belt and found it was LOUDsomething I was
intent on avoiding. The owner thought it was because of
the belt but perhaps he was wrong. All I can say is
that my belt is quiet and doesnt slip.<br><br>Prop
pressure to motor: I use a "pillow block"a bearing (about
$35) that fits around the shaft and is secured to a
convenient floor. Mine swivels in two planes so as to be
self adjusting to the shaft angle. It is an extremely
tight fit to the shaft and took some work getting it
mounted. It has integral grease fittings for the bearing.
I dont know whether something more than that might
be needed for your 14 tonsas you know my boat is a
long way from that. I saw the pillow block arrangement
on another electric launch, luckily, since Id
already spent some head-scratching time over the problem.
It has worked fine.<br><br>Motor to boat: with the
pillow block arrangement as a "thrust bearing", the
motor itself doesnt receive much of the forward thrust
of the prop. I made my own motor mount out of "
Okoume plywood and stainless bolts. (Ive seen somewhat
similar arrangements out of aluminum plate but Im not a
welder. Wood is what I do!) I constructed the motor mount
so that tightening a set of bolts allowed me to
adjust the belt tension. I have positive tensioning
ability by tightening the nuts as opposed to a pivot
arrangement (like on a car alternator) that must be held in
place, in tension, while securing nuts are tightened.
Again, so far its worked fine for me but I dont know
what effects the extra size might have for
you.<br><br>Im glad to see by your recent questions that it
looks like you are seriously moving forward. Some of
these things you just cant answer until you get in
there and do it and see what works. In the end I think
its just not as hard as it seems!<br><br>Keep us
posted.<br><br>Larry

Hi James and all,<br>Old diesels do make "the"
best moorings. Ya have to drain and clean it out well
before you place it. But, In a bad storm moorings are
better to boats then docks. Plus, If you have visiting
friends they'll have a no cost, safe place to tie
up.<br>Joe

James,<br>Depending upon condition, your old
broken diesel may have a number of salvageable parts.
Yes, there are old diesel graveyards where blocks are
stripped for heads, starters, pump cores, etc.<br>Even if
your old engine is only a rusted mass, this too has
value as scrap iron. You might try calling several
repair shops to determine if there is any core value to
your engine. Otherwise you can sell as scrap iron.
Scrap is sold by the pound. Check the yellow pages.
There is no reason disposal should cost you anything.
If your lucky, you may even make a few dollars. Good
luck.<br>bud

Does anyone have a suggestion as to what I can do
with my old broken diesel? I mean, where do you put
them? Is there an old diesel graveyard I don't know
about, or do I cut it up in little pieces and quietly
dispose of it? Anyway, are there any parts of the old
diesel or transmission I should keep that will benefit
an electric motor?<br><br>James

Larry,<br><br>I have a quick question regarding
mounting the motor to the prop shaft. How do you do it?
Also, what does a guy need to protect the movement of
the prop against the motor. Oh yeah, what is the best
way to mount down the motor so it can take the force
of the prop. Since my boat is 14 tons, I imagine the
force on the motor would be high if I didn't have any
way of protecting it. <br><br>Thanks, <br>James

Gary,<br>Theres been a lot of argument about the
validity of thrust as a power measurment. We are not
qualfied to enter the argument, however thrust is
deftinely variable upon speed. Some EBBA members have
enlightened the argument, but we have stayed out of the
way!<br>The Sneakeasy,which belongs to a friend, is in the
back of the barn now, and has been reconverted from
solar electric to combustion. We needed a quick solar
project and assembled a package from RAY, Photocomm, etc.
in order to travel from Knoxville,Tennessee to
Appalachacola,Florida via sunshine. Yes, the Sneakeasy was a great
hull, but the transom was not optimum for the 2.4kt
average speed under solar. Bolger and Ray both thought
the transom wrong, but the overall length to beam
ratio carried us thru. Great boat! <br><br>If you want
an afternoon speed machine the Sneakeasy will fill
the bill. With enough power,it will go beyond the
conventional launch in top speed without eating up too many
amps. Course everything is a trade off, and the
slightly larger Bolger power sharpies might be better
overall, as they have raked disp. type transoms and would
offer greater range at typical speeds. <br><br>Good
luck with your outboard project.Thats a good way to
have a propulsion unit without spending a lot of
money. The Sneakeasy, with motor tilted up, drew about 6
inches of water. Sure was useful in finding shallow
water anchorages!<br><br>Happy boating,<br>bud

What a lovely description of your cruise, Paul I,
also, was out this morning in temperatures almost
identical to yours, although I will say that there are no
flurries on the horizon and weve had relatively mild
weather here in the Northwest for several weeks or
so.<br><br>My cruise lasted about an hour and half, setting out
about 8:00 this morning. I recently installed a small
compass and was interested to see how accurate it would
be. Turned out to be quite good, although initially I
misread my chart and lined up on the wrong point,
thinking I was out by about 10 degrees as a result.
Happily I discovered my error. I will need to practice
before offering my services as navigator on the
Victoria/Maui race.<br><br>I cruised (in silence! Oh, what a
joy, indeed!) at about 5.3 mph and drew about 30A at
that speed. A loon was unconcerned by my close passage
but two Canada Geese decided I was too close and
"barked" their protest quite loudly. An iridescent-blue
swallow circled my boat about ten timeslooking for a
nesting spot in the "high rent district"?<br><br>You
mentioned that your "electronics wintered well". Another
joy. I still own a 31 ketch with inboard diesel. I
also still have to face getting her ready for the
season3 filters, an oil change, and wondering what the
winter weather has done to my fuel. The cost of her
spring engine maintenance will likely exceed my entire
seasons operational cost for my electric
launch.<br><br>After my 1 hour cruise, Id covered 6.6 mi. and
"burned" 34.9Anot enough to even bother
recharging.<br><br>Larry