http://members.cox.net/sholley1/electric.htm

"A few years back I was impressed when I saw a "dock maintainance
barge" tooling around the cove in our Marina under the power of a
little 12 volt trolling motor. It was small, old, but the persistance
of the little thing moved the barge around quite well. I proceeded
down to my boat, and embarked on the following procedure to go
sailing."

"NOTE: There is no neat formula or correlation between thrust and
horsepower. However, I read a comparison that measured a 6 hp gas
outboard produced just over 130 lbs of thrust, so that would class the
107 Motorguide in the realm of a 5 hp gas (give or take a little).
Thats not a lot of power, but ample for my needs. I don't know how I'd
fare towing in another boat, but I'll include towing in "tests to
come"."

http://www.geocities.com/Yosemite/Fo..._outboard.html

Auxilliary Power Requirements with Electricity

"A typical trolling motor is designed to push a displacement hull at a
maximum of about 2 to 3 miles per hour. Therefore, I determined to use
the highest thrust 12 volt electric trolling motor that I could
purchase and see where that would lead. In this case, a Motorguide
model T47 motor with a 36 inch shaft length was commonly available at
the local Kmart stores. This motor draws about 50 amps at maximum
speed and is rated to produce 47 pounds of thrust. Replacing the
propeller with a two blade (power) design from the three blade (weed
free design) included with the motor should result in the required
combination of low shaft speed and high thrust. This motor, combined
with a bank of two new fully charged group 27 deep cycle batteries,
could operate at maximum thrust for about 2.5 hours. In theory, the
calculations said that this combination would propel my Com-Pac at
just under three knots. This would meet my stated goal of a 5 mile
range under power with some safety margin."

For whatever it is worth to you, I can drive my 16 ft sailing skiff at 3.6
mph using an Endura 30 drawing 30 amps.

BS

"Mic" wrote in message
...
http://members.cox.net/sholley1/electric.htm

"A few years back I was impressed when I saw a "dock maintainance
barge" tooling around the cove in our Marina under the power of a
little 12 volt trolling motor. It was small, old, but the persistance
of the little thing moved the barge around quite well. I proceeded
down to my boat, and embarked on the following procedure to go
sailing."

"NOTE: There is no neat formula or correlation between thrust and
horsepower. However, I read a comparison that measured a 6 hp gas
outboard produced just over 130 lbs of thrust, so that would class the
107 Motorguide in the realm of a 5 hp gas (give or take a little).
Thats not a lot of power, but ample for my needs. I don't know how I'd
fare towing in another boat, but I'll include towing in "tests to
come"."

http://www.geocities.com/Yosemite/Fo..._outboard.html

Auxilliary Power Requirements with Electricity

"A typical trolling motor is designed to push a displacement hull at a
maximum of about 2 to 3 miles per hour. Therefore, I determined to use
the highest thrust 12 volt electric trolling motor that I could
purchase and see where that would lead. In this case, a Motorguide
model T47 motor with a 36 inch shaft length was commonly available at
the local Kmart stores. This motor draws about 50 amps at maximum
speed and is rated to produce 47 pounds of thrust. Replacing the
propeller with a two blade (power) design from the three blade (weed
free design) included with the motor should result in the required
combination of low shaft speed and high thrust. This motor, combined
with a bank of two new fully charged group 27 deep cycle batteries,
could operate at maximum thrust for about 2.5 hours. In theory, the
calculations said that this combination would propel my Com-Pac at
just under three knots. This would meet my stated goal of a 5 mile
range under power with some safety margin."

On Sun, 29 May 2005 21:32:39 GMT, (Mic) wrote:

http://members.cox.net/sholley1/electric.htm

"A few years back I was impressed when I saw a "dock maintainance
barge" tooling around the cove in our Marina under the power of a
little 12 volt trolling motor. It was small, old, but the persistance
of the little thing moved the barge around quite well. I proceeded
down to my boat, and embarked on the following procedure to go
sailing."

"NOTE: There is no neat formula or correlation between thrust and
horsepower. However, I read a comparison that measured a 6 hp gas
outboard produced just over 130 lbs of thrust, so that would class the
107 Motorguide in the realm of a 5 hp gas (give or take a little).
Thats not a lot of power, but ample for my needs. I don't know how I'd
fare towing in another boat, but I'll include towing in "tests to
come"."

http://www.geocities.com/Yosemite/Fo..._outboard.html

Auxilliary Power Requirements with Electricity

"A typical trolling motor is designed to push a displacement hull at a
maximum of about 2 to 3 miles per hour. Therefore, I determined to use
the highest thrust 12 volt electric trolling motor that I could
purchase and see where that would lead. In this case, a Motorguide
model T47 motor with a 36 inch shaft length was commonly available at
the local Kmart stores. This motor draws about 50 amps at maximum
speed and is rated to produce 47 pounds of thrust. Replacing the
propeller with a two blade (power) design from the three blade (weed
free design) included with the motor should result in the required
combination of low shaft speed and high thrust. This motor, combined
with a bank of two new fully charged group 27 deep cycle batteries,
could operate at maximum thrust for about 2.5 hours. In theory, the
calculations said that this combination would propel my Com-Pac at
just under three knots. This would meet my stated goal of a 5 mile
range under power with some safety margin."

A number of years ago I replaced the gas outboard on an Irwin 24 with
the cheapest trolling motor at the local Walmart. This was on Lake
Lanier, not in the ocean, but it was more than sufficient for driving
this boat in and out of the marina. I am not sure what the thrust
rating was, but I paid $150 for both the motor and a deep cycle
trolling motor battery. With a solar panel on the cabin roof I never
needed shore power to keep it charged up enough for going in and out
of the marina 2 or 3 times a week.

The boat I am building now (a 7 meter Eco7 catamaran) will have two
electric trolling motors for auxilliary.


Weebles Wobble
(but they don't fall down)

Hey, Weeb...

Are you still on Lanier? I've got an option contract on the house but
they've not exercised, just paying the renewals, as yet, so I'm still here
while I'm not on the boat refitting (which means I get about a week a month
at home)....

L8R

Skip, near the Habersham Condos

--
Morgan 461 #2
SV Flying Pig
http://tinyurl.com/384p2

"Twenty years from now you will be more disappointed by the things you
didn't do than by the ones you did do. So throw off the bowlines. Sail
away from the safe harbor. Catch the trade winds in your sails. Explore.
Dream. Discover." - Mark Twain

wrote in message
news
On Sun, 29 May 2005 21:32:39 GMT, (Mic) wrote:

http://members.cox.net/sholley1/electric.htm

"A few years back I was impressed when I saw a "dock maintainance
barge" tooling around the cove in our Marina under the power of a
little 12 volt trolling motor. It was small, old, but the persistance
of the little thing moved the barge around quite well. I proceeded
down to my boat, and embarked on the following procedure to go
sailing."

"NOTE: There is no neat formula or correlation between thrust and
horsepower. However, I read a comparison that measured a 6 hp gas
outboard produced just over 130 lbs of thrust, so that would class the
107 Motorguide in the realm of a 5 hp gas (give or take a little).
Thats not a lot of power, but ample for my needs. I don't know how I'd
fare towing in another boat, but I'll include towing in "tests to
come"."

http://www.geocities.com/Yosemite/Fo..._outboard.html

Auxilliary Power Requirements with Electricity

"A typical trolling motor is designed to push a displacement hull at a
maximum of about 2 to 3 miles per hour. Therefore, I determined to use
the highest thrust 12 volt electric trolling motor that I could
purchase and see where that would lead. In this case, a Motorguide
model T47 motor with a 36 inch shaft length was commonly available at
the local Kmart stores. This motor draws about 50 amps at maximum
speed and is rated to produce 47 pounds of thrust. Replacing the
propeller with a two blade (power) design from the three blade (weed
free design) included with the motor should result in the required
combination of low shaft speed and high thrust. This motor, combined
with a bank of two new fully charged group 27 deep cycle batteries,
could operate at maximum thrust for about 2.5 hours. In theory, the
calculations said that this combination would propel my Com-Pac at
just under three knots. This would meet my stated goal of a 5 mile
range under power with some safety margin."

A number of years ago I replaced the gas outboard on an Irwin 24 with
the cheapest trolling motor at the local Walmart. This was on Lake
Lanier, not in the ocean, but it was more than sufficient for driving
this boat in and out of the marina. I am not sure what the thrust
rating was, but I paid $150 for both the motor and a deep cycle
trolling motor battery. With a solar panel on the cabin roof I never
needed shore power to keep it charged up enough for going in and out
of the marina 2 or 3 times a week.

The boat I am building now (a 7 meter Eco7 catamaran) will have two
electric trolling motors for auxilliary.


Weebles Wobble
(but they don't fall down)

On Tue, 31 May 2005 15:37:05 -0400, "Skip Gundlach on wifi"
skipgundlach.sez.remove.this.part@earthlink.(fish catcher)net wrote:

Hey, Weeb...

Are you still on Lanier? I've got an option contract on the house but
they've not exercised, just paying the renewals, as yet, so I'm still here
while I'm not on the boat refitting (which means I get about a week a month
at home)....

L8R

Skip, near the Habersham Condos

I live in Lilburn, but have no boat currently
(building one as we speak)


Weebles Wobble
(but they don't fall down)

Perpetuated Motion
Electric propulsion for boats: A century-old technology may just be
the wave of the future

LINK:

http://www.cruisingworld.com/article...ID=396&catID=0

" Advocates for diesel-electric propulsion list among its virtues that
it's clean, quiet, efficient, and requires very little maintenance.
Another advantage frequently noted in connection with the STI system
is the ability to make electricity--to "regenerate"--when the boat is
under sail."

"While internal-combustion engines are typically described by their
horsepower rating, STI's motors are named for the torque they develop.
An ST 37 puts out 37 foot-pounds of torque or 6 horsepower; Tether
recommends using it on monohulls up to 32 feet and 10 tons or to
replace diesel engines of up to 24 horsepower. An ST 74 puts out 74
foot-pounds of torque or 12 horsepower; Tether recommends using it on
monohulls up to 50 feet and 16 tons or to replace diesel engines of up
to 48 horsepower."

On Thu, 02 Jun 2005 12:43:35 GMT, (Mic) wrote:

Perpetuated Motion
Electric propulsion for boats: A century-old technology may just be
the wave of the future

LINK:

http://www.cruisingworld.com/article...ID=396&catID=0

" Advocates for diesel-electric propulsion list among its virtues that
it's clean, quiet, efficient, and requires very little maintenance.
Another advantage frequently noted in connection with the STI system
is the ability to make electricity--to "regenerate"--when the boat is
under sail."

"While internal-combustion engines are typically described by their
horsepower rating, STI's motors are named for the torque they develop.
An ST 37 puts out 37 foot-pounds of torque or 6 horsepower; Tether
recommends using it on monohulls up to 32 feet and 10 tons or to
replace diesel engines of up to 24 horsepower. An ST 74 puts out 74
foot-pounds of torque or 12 horsepower; Tether recommends using it on
monohulls up to 50 feet and 16 tons or to replace diesel engines of up
to 48 horsepower."

The ST37 is right in the range for my current light cruiser, and the
ganged ST74 is appropriate for my anticipated next boat, which would
be a modified full-keeler.

I'm watching this technology like a hawk. It makes a lot of sense on a
number of levels, but of course, it isn't for everyone.

In the meantime, I'm replacing the exhaust end of my old Atomic 4....

R.

On Thu, 02 Jun 2005 10:13:43 -0400, rhys wrote:

On Thu, 02 Jun 2005 12:43:35 GMT, (Mic) wrote:

Perpetuated Motion
Electric propulsion for boats: A century-old technology may just be
the wave of the future

LINK:

http://www.cruisingworld.com/article...ID=396&catID=0

" Advocates for diesel-electric propulsion list among its virtues that
it's clean, quiet, efficient, and requires very little maintenance.
Another advantage frequently noted in connection with the STI system
is the ability to make electricity--to "regenerate"--when the boat is
under sail."

"While internal-combustion engines are typically described by their
horsepower rating, STI's motors are named for the torque they develop.
An ST 37 puts out 37 foot-pounds of torque or 6 horsepower; Tether
recommends using it on monohulls up to 32 feet and 10 tons or to
replace diesel engines of up to 24 horsepower. An ST 74 puts out 74
foot-pounds of torque or 12 horsepower; Tether recommends using it on
monohulls up to 50 feet and 16 tons or to replace diesel engines of up
to 48 horsepower."

The ST37 is right in the range for my current light cruiser, and the
ganged ST74 is appropriate for my anticipated next boat, which would
be a modified full-keeler.

I'm watching this technology like a hawk. It makes a lot of sense on a
number of levels, but of course, it isn't for everyone.

In the meantime, I'm replacing the exhaust end of my old Atomic 4....

R.
The problem with the STI system is the size of the battery pack
required for the 144 volt system. It takes up a lot of space and adds
a lot of weight. There are a lot of advantages to their system as
well, especially as was already noted the regeneration under sail
appeals for long passagemaking.

Hopefully as the technology evolves a better and lighter battery
system will be brought online. As a lover of multihulls, the current
battery system takes their system off the table for me.


Weebles Wobble
(but they don't fall down)

On Thu, 02 Jun 2005 13:27:27 -0400,
wrote:


The problem with the STI system is the size of the battery pack
required for the 144 volt system. It takes up a lot of space and adds
a lot of weight. There are a lot of advantages to their system as
well, especially as was already noted the regeneration under sail
appeals for long passagemaking.

Hopefully as the technology evolves a better and lighter battery
system will be brought online. As a lover of multihulls, the current
battery system takes their system off the table for me.

I can see that with a multihull. My current boat wouldn't enjoy 12
batteries, all that copper and the required charger, either, But
certainly there are passagemakers and full keelers that could have the
batteries low and in return shrink the size of the diesel tanks to
whatever would reasonably cope with the genset's occasional use.

I also anticipate a lot of competition in this area, which I hope will
spur further savings in weight and complexity.

R.

On Mon, 06 Jun 2005 13:41:50 -0400, rhys wrote:

On Thu, 02 Jun 2005 13:27:27 -0400,
wrote:


The problem with the STI system is the size of the battery pack
required for the 144 volt system. It takes up a lot of space and adds
a lot of weight. There are a lot of advantages to their system as
well, especially as was already noted the regeneration under sail
appeals for long passagemaking.

Hopefully as the technology evolves a better and lighter battery
system will be brought online. As a lover of multihulls, the current
battery system takes their system off the table for me.

I can see that with a multihull. My current boat wouldn't enjoy 12
batteries, all that copper and the required charger, either, But
certainly there are passagemakers and full keelers that could have the
batteries low and in return shrink the size of the diesel tanks to
whatever would reasonably cope with the genset's occasional use.

I also anticipate a lot of competition in this area, which I hope will
spur further savings in weight and complexity.

R.
I agree. I think STI is a good first offering that will be built on by
others in the near future. I am not sure what the benefits are of
using the 144 volt motor vs a 24 or 48 volt system. I use an electric
truck at work that does quite well on a 48 volt system and have
wondered if someone will follow up and offer a system that can use a
more practical sized battery system.


Weebles Wobble
(but they don't fall down)