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You can write directly to Solomon Technologies,
PO Box 314, Benedict, MD. 20612. You can also call
me directly at 301-274-4479. I apologize for the
inconvenience but our web site is not up yet because someone
else had registered Solomontech.com. We were able to
get the name but are just waiting for the paperwork.
Meanwhile, if you call or write we can forward to you a
package that will explain most or all of your questions.
Again....if you have any other questions do not hesitate to
call the # above....&#92;<br>Dave Tether

I disagree with your thoughts that electric motor
drive system are more "expensive than deisel because
they are designed to last longer". I have been
involved in the sales and applications DC and AC motors
and controlers for variable speed systems in
industrial systems for 30 years. The quality has incresed
and the prices have decreased. The problem with
marine use is that there is a lack of competition and/
or a lack crossover from the industrial world to the
marine world. A DC Motor has brushes. Todays motors have
brushes which are desigend to run for 10000 hours when
properly applied. Both AC and DC Motors have bearing they
have a MTBF (mean time between failure)equal to or
beter than the brushes in DC Motors. The cost of
controls (amplifiers) in the industrial application has
gone down 10 fold in the last 20 years but these
controls have not been applied to marine applications for
whatever reason. The only other item in the system is
batteries and due to the push for electric cars there is a
lot of work being done to make them have better
capacity and lower the cost and weight at the same time. I
feel that it is feasable to put together an effecient
cost effective electric marine propulsion system with
todays componets that will be be every bit as good if
not better then the fossil fuel drive system that are
being used today at a price that is competive to fossil
fuel propulsion systems.

I agree that a cost effective system can be
developed for marine propulsion using off the shelf
technologies. I do not, however, agree that the disign life
will be acieved unless the motor has been reworked for
the marine industry. Salty air, electrolysis and
water will eventually have its way with brushes and the
other internal parts of the motor if it is not modified
for the marine environment. The additional
modifications will make the motor some what more expensive but
cost effective anyway. <br> It is for these reasons,
and to develop a motor designed for the right RPM's
to push props, that Solomon Technologies productized
the Solo 6HP and 10 HP Electric Wheel. They are water
proof down to 20 feet, designed for 1200 RPM's,
brushless, protected from electrolysis and can regenerate in
sailboats. These motors are a bit more expensive because of
low production quantities and these additional
benfits that have been designed in. Are they still cost
effective ? Yes. When you go to the out years (10 +) and
you have spent an additional $4,000 for maintenance
and you must rebuild that diesel, replace fuel
injectors, repair transmission...etc. then the electric
motor is not only cost effective but comes with much
less hastle and is quiet too. It is now only a matter
of time until folks like you all will be considered
visionaries because I truly believe that within 10 years all
new production boats will be electric or diesel
electric hybrids. There were limitations to older
electrics....those days have changed...the new electrics can produce
equal the power and better performance than any diesel
or gasoline engine. And even today and for the past
30 years the fastes ships in the Navy's inventory
(any Navy...US, Russian, British, French) are all
diesel electric or nuclear electric hybrids...It's about
time that the civilian sector is given the opportunity
to do the same.

Being the owner of the 38-footer,(and totally
ignorant about electric propulsion!) I'm very happy to see
qualified discussion about the subject.<br>1) As mentioned
by EWHEL, there have been boats utilizing electric
drives for many years. Why didn't it ever before filter
down to us little civilian guys?<br>2) As US
government (coast-guard) is so preoccupied with the
live-aboards letting out a bit of waste from the heads, foul
anti-fouling paint etc. why not take the big step and try to
help keep the bilges clean by subsidizing compagnies
who really could make a difference in the mess we
boaters leave in the water? Show me a boat that didn't at
one time overfill the dieseltank, or get oil in the
bilge. So the bilges get pumped during the night!
Doesn't really help, does it?<br>Wouldn't it help with a
bit of government incentive?<br>3) Yes, a new diesel
IS cheaper than changing the whole system over to
electric! Even figuring the years of use! My old diesel
gave up after 30 years (and 5 different owners) If I
count in the batteries needed (AND the replacement of
these once in a while) + the price for The Electric
Wheel, + whatever else might have to be included, it
will be a very expensive change. I would like for
somebody with the knowledge needed in this to set up the
pro's and con's here. We would all like the quiet, the
cleanliness and ease of electric propulsion, but not at
double the cost. <br>I'll cheer for anybody who has the
know-how and the energy to work on this matter - I forget
HOW many boats are roaming the waters in the US
alone, but it must be profitable to get a business going
pushing all of us around. <br>But as long as it's half
the price to buy a brand new YANMAR out of the box,
guess what???<br>I WANT electric propulsion, but I can
stay tied off in the marina for another year or two
for the extra I'll have to pay for it!<br>And that'll
give me enough time to save up for a
diesel....<br>What a choice!!!

There are many problems with the development of
effecient electric propulsion system for non military
applications may of which can be blamed on a lack of available
funds for this purpose. unfortunatly until private
industry can see the market the development of such will
be limited to a few visionaries who are willing to
spend the time and their own money to do this. We can
however benifit from other sources of of development.
private industry has had a need for years for corrosion
resistant motors. These are avaible off the shelf, as a
matter of fact I know of one company who is producing
all stainless motors as cheaply as other so callled
sever duty motors. Servo motors have been in sever duty
for over 20 years and some are avaible with effencies
in excess of 90%.

There are many problems with the development of
effecient electric propulsion system for non military
applications may of which can be blamed on a lack of available
funds for this purpose. unfortunatly until private
industry can see the market the development of such will
be limited to a few visionaries who are willing to
spend the time and their own money to do this. We can
however benifit from other sources of of development.
private industry has had a need for years for corrosion
resistant motors. These are avaible off the shelf, as a
matter of fact I know of one company who is producing
all stainless motors as cheaply as other so callled
sever duty motors. Servo motors have been in sever duty
for over 20 years and some are avaible with effencies
in excess of 90%. <br> In the late 60's and early 70
I served on board a nuclear submarine. We had an
emergency propulsion system that used a 150 HP motor to
drive an 8000 ton displacement submarine through the
water at a speed in excess of 4 knots, under battery
power. Now thats not a speed record but it is very
inpressive when you think about it. You have a 38ft
displacemtn hull. you water line length is prounbly around
32ft. That means your a max. effecient speed is around
8 knotts. I firmly believe that an electric
propulsion system could be put into you boat which could
propel you through the water at 8 knots for 6-8 hours at
a streatch and would not cost you much more than
the cost of replacing you diesel. The real problem is
in selecting the batteries to use. I could go into
more details on this matter however I shouldn't hog up
so much space. If you want more information as to my
thoughts please feel free to E mail me at my web address
donaldbaer@...

Amen Kirsti....and read "Polluting for Pleasure"
by Andre Mele..It will strenghten your resolve. The
Waste and Pollution associated with pleasure boating is
appauling. And the folks associated with this association
(Elco, Duffy, Donaldbaer, Solomon Technologies, Mr.
Morton Ray and even NASA) are living proof that there is
a market and it is growing. Its growing because
today the technology does exist to have "drop-in
replacements" for diesels and gasoline motors that not only
quiet and clean, but just as powerful with much longer
operational life. Batteries were a hurtle in the past but
today they are getting better every day and fossil fuel
generator technologies provide infinite range while using
fossil fuel sparingly and efficiently. You need only
define your cycle of use to determine average continuous
run time then select the hybrid combination to
achieve it. It is only a matter of time now.

AMEN to that. This is especialy true when one
considers that most boats spend most of their time going
through the water at speed less than 10 knots. the speed
limit for marinas, most harbors and many many lakes is
5 mph. Its only in the open water that boats go
faster or in specialy selected areas that boats go any
faster.

I just mounted a Minn Kota EM44 on the skeg of my
17 foot Cape Cod Cat. I cut away a section of the
keel to recess the motor and permanently fiberglassed
it in. The wiring is in a tube sealed to the hull
and taken to above the water line in the
bilge.<br>This boat is very large for a 17 footer (for those of
you unfamiliar with catboats). It has a 8 foot beam
and a displacement of 2400 pounds.<br>The motor moves
the boat along very nicely and silently. I do not
have a knotmeter, so I am only guessing, but I'd say
it glides along at about 4 mph. After it gets up to
speed, half power keeps it there.<br>I only got it back
in the water last week.<br>I'll report back in a few
weeks with more performance details.

This is for ernie_M_2000<br><br> I have delevoped
two spreed sheet in Excel which provide some help in
motor sizing for selected propelers. Although they only
provide best case scenario they are helpful in playing
what if. They provide a place to start. If you or
anyone else out there would like to have them I will be
glad to share them. They are in excel. They use some
of Dave Gerr calculation form the propeller
handbook. The first on calulates the Bollard Thrust and
RPM's based on the hull configuration (Water line
length, width and hull depth) The second will show the
theoritcal performance of a given propeller (diameter and
Pitch) at various shaft RPM's. If you would like them
you can E Mail me at Donaldbaer@...

I have a complete inboard electric motor system
to sell, It was used to push my wooden catboat. It
includes a 4hp Advanced DC motor,Pulse width modultor,
on-off&foward-reverse contactors, potbox, digital monitoring system and
six trojan t-105 batteries.

Hi group, I am currently planning to repower my
35' trimaran to electric and need to find someone
with direct experience sizing motors and other
important considerations for such a project. Anyone with
this type of knowledge please post or email me. Also
if Oconaill has the Motor System which was posted on
11/28 I would like to discuss how that might work for
my conversion.

I found this while searching out e boat sites. Perhaps this will be competition for the e- outboards of Ray. Just an FYI for the group.<br><a href= target=new></a>

Oconail,<br><br>How much are you asking for the setup? How many hours on the system? How old are the batteries? How big was the catboat and how well did it perform?<br><br>Frank

I launched my 23' fantail at the end of August,
subsequently worked on installing the propulsion system
components and, a few days ago, managed to take her out for
her maiden voyage. Since then I've had her out a
couple more times and can now give a preliminary
report.<br><br>Most important to me, the motor is extremely quiet
even at speed. This was one of my two prime reasons
for going with electric propulsion but until the boat
was actually in the water and moving along at
cruising speed I just had no idea how it would really
sound. As it is, the noise of the bow wave is louder
than the low hum of the motor. So this aspect was a
resounding, important success.<br><br>The othe big question
was speed/range. I am using a 13 X 12 prop that was
given to me--quite a bit smaller than I'd been
intending. But I thought that I'd see what she would do with
that setup. <br><br>What I find is that the boat's
most efficient speed seems to be around 4.3kts or so.
At that rate she draws 20A (just under 1 hp). Since
I don't want to draw my battery bank down below
about 70%, that gives me a realistic range of 8.9 hours
(as calculated by my e-meter) or roughly 36 mi.! I'd
been hoping for around 25 which will be about the most
I would ever need. The farthest I've "cranked it
up" so far is 60A which is the equivalent of about
3hp. (The motor is rated at 4.1hp continuous/ 6hp
peak.) At 60A she does 6.2kts but has a range of only
17mi. or so. But 6.2kts seems like bombing along (and
in a straight line!) to a guy who's used to sailing,
paddling, or rowing little boats around this
lake!<br><br>Larry

You could do a "Hull drag" test with the help of
a friend and a second boat. You will need a "good"
knotmeter(0~10 Kt ? ) and a calibrated scale (0~100lbs. maybe
150 lbs the kind with hooks on both ends). The idea
is to measure the pounds of "pull" (on tow line)at
increasing speeds. Like 4kts. 25lbs, 5kts. 32lbs, and so on.
Then if you want to calcualte the power your hull is
dissipating (power your going to need also) then multiply the
speed (in knots) times the drag (in pounds) times
0.003068 (corrects for differences in units). Collect as
many data point as you can and make the "runs" inboth
directions to lower the errors.(wind~current)<br>Have
fun<br>Joe<br>ECB

To figure out what electric HP you need first
start with the motor that WAS in the vessel. Usually
the manufacturers are pretty good a determining the
appropriate fossil fuel HP. Then divide by 3 for a coarse
guestimate. If you have enough room to size the prop up a
little, say from 14" to 16" then you can usually reduce
the HP to 1/4 instead of 1/3. If you list the current
engine HP, prop size, and displacement I could help you
even more. After gauging HP you can then use the
aperage/voltage to determine a burn rate and get the battery pack
sized right. This will require you to guess at a motor
technology and the voltage. It your trimaran is over 16,000
lbs you will probably need to call Solomon
Technologies and get an Electric Wheel motor. There aren't
many people producing marine motors much over 4 Kw.

Congradulations on you maiden voyage. sounds liek
youve got what you were looking for. I assume you are
using a 48 volt system. I plugged you prop data into
the modeling spread sheet that I am attempting and
using a .6 % slip factor came up with a 20.31 amps at
4.2 kts and 65.34 amps at 6.2 kts. It also said your
shaft rpms was at 708 and 1013 respectivly. Can you
tell me how close I am at guestimating since I am
trying to get some data to validate my model. Also if
and when you change to another prop what are you
planning on changing to. I'd like to plug that data into
my model and see what your performance would be
like.<br><br>Don

The system is 36V, using an Advanced A89-4001
motor and a 245A battery bank. I've had the boat out a
couple more times now, but with guests--who get in the
way of accurate measurements! But the numbers I
previously posted seem to be holding true.<br><br>Originally
I'd been thinking of an oversquare 16" dia. prop. I
would be very interested, indeed, to see what you think
the differences would be. Thanks.<br><br>Larry

Hi Folks,<br>My names Joe Peek, I've lurked long
enough to read all the posts and find out whats "up"
with the lister here..and I've enjoyed all of the
posts and peoples endevors. For myself, I own a new
company called "Electro Cruise Boats", In a few months
we'll bring a "New" Electric Boat into the market. I
don't intend to "sell" my product here on the list,
just exchange ideas and enjoy hearing others stories
of what there doing....E-boat wise. I should have
introduced myself before I posted a replay to the question
about sizing a motor for a hull. The method I described
works very well (it's fun to do) and deliver good data
on power requirments...(real world) no guess work. I
did the same test's about 3 months ago and the stuff
to do it cost $65.<br><br>Joe