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Re: [AtkinBoats] Re:electric drive for a tunnel stern?

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  • derbyrm
    If you look at mpg figures for hybrid automobiles, it quickly becomes apparent that electric power is great for stop/go applications; but not worth the effort
    Message 1 of 15 , Feb 16, 2007
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      If you look at mpg figures for hybrid automobiles, it quickly becomes apparent that electric power is great for stop/go applications; but not worth the effort for the sort of steady state effort that most boat propulsion systems are used in.

      Every time you convert from one form of energy to a different form, you lose a significant percentage to heating the atmosphere.
      chemical => mechanical -- direct connection of gas engine to prop
      vs
      chemical => electrical => mechanical -- battery to motor to prop
      vs
      chemical => mechanical => electrical => mechanical -- driving electric motor with genset

      Roger
      derbyrm@...
      http://home.insightbb.com/~derbyrm

      ----- Original Message -----
      From: Ken Grome
      To: AtkinBoats@yahoogroups.com
      Sent: Friday, February 16, 2007 10:33 AM
      Subject: Re: [AtkinBoats] Re:electric drive for a tunnel stern?


      Good recommendation Sal's Dad, I had forgotten all about Twinkle!

      I still don't think a tunnel hull is the ideal design for an electric motor
      because it takes a lot of power to lift the water into the tunnel. Gas
      engines can easily produce this much power but electrics would probably drain
      batteries fast in this effort.

      Then again for short distances an electric motor in a tunnel hull like Twinkle
      might be just the thing, although I agree that this boat can probably be
      built lighter and still be safe and plenty strong enough for its intended use
      -- and lighter is often better when limited power is available.

      Sincerely,
      Kenneth Grome
      Bagacay Boatworks
      www.bagacayboatworks.com

      On Friday 16 February 2007 19:53, Sal's Dad wrote:
      > Look at Twinkle http://www.boat-links.com/Atkinco/Utilities/Twinkle.html.
      > "3 h.p. will be ample for speeds up to six miles an hour."





      [Non-text portions of this message have been removed]
    • Bruce C. Dillahunty
      ... I certainly see your point, but... The River Belle (35 tunnel hull) was spec ed to have 80hp and run 15mph... this would be above hull speed (planing)...
      Message 2 of 15 , Feb 16, 2007
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        Ken Grome wrote:
        > I still don't think a tunnel hull is the ideal design for an electric motor
        > because it takes a lot of power to lift the water into the tunnel. Gas
        > engines can easily produce this much power but electrics would probably drain
        > batteries fast in this effort.
        >
        > Then again for short distances an electric motor in a tunnel hull like Twinkle
        > might be just the thing, although I agree that this boat can probably be
        > built lighter and still be safe and plenty strong enough for its intended use
        > -- and lighter is often better when limited power is available.
        >
        I certainly see your point, but... The River Belle (35' tunnel hull) was
        spec'ed to have 80hp and run 15mph... this would be above hull speed
        (planing)... for the size boat and speed, that's low power (isn't it???)
        compared to many of today's boats.

        If they were efficient (good speed at low hp) with gas/diesel then they
        should still be efficient with electric, I would think... just thinking,
        here :-)

        Anybody know how they do at displacement speeds?

        Other than the tunnel, it seems like a similar hull to the Mundoo series
        (http://www.duckflatwoodenboats.com/mainpages/mundoo.php) which have
        been doing well with electric... guess it all comes down to the tunnel
        effect.

        Bruce

        --
        Bruce Dillahunty
        bdillahu@...
        http://www.craftacraft.com
      • Lewis E. Gordon
        Twinkle is a nice design, but don t forget the weight of the batteries you need to carry along. At 16 feet and flat bottomed it might be difficult to get the
        Message 3 of 15 , Feb 16, 2007
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          Twinkle is a nice design, but don't forget the weight of the batteries
          you need to carry along. At 16 feet and flat bottomed it might be
          difficult to get the batteries low enough to get be ultra "seaworthy".
          Also at 16 feet, MotoSkiff, being V-bottomed might be a better choice.
          While not a tunnel stern design, the draft is a modest 11 inches and
          the propeller is well protected. And, she was designed for low power
          and to be easily built.

          There is also Sixteen Too and Heron (tunnel sterned) at 17 feet and
          not as easy to build. I used to boat off Brunswick County, NC and also
          up in the Beaufort (NC) area. I can just imagine cruising along with
          quiet electric power in MotoSkiff up the Lockwood Folly river and
          seeing the alligators sunning and watching the ospreys fishing. It was
          a very special area in the coastal Carolinas.

          Lewis,

          --- In AtkinBoats@yahoogroups.com, Ken Grome <bagacayboatworks@...> wrote:
          >
          > Good recommendation Sal's Dad, I had forgotten all about Twinkle!
          >
          > I still don't think a tunnel hull is the ideal design for an
          electric motor
          > because it takes a lot of power to lift the water into the tunnel. Gas
          > engines can easily produce this much power but electrics would
          probably drain
          > batteries fast in this effort.
          >
          > Then again for short distances an electric motor in a tunnel hull
          like Twinkle
          > might be just the thing, although I agree that this boat can
          probably be
          > built lighter and still be safe and plenty strong enough for its
          intended use
          > -- and lighter is often better when limited power is available.
          >
          > Sincerely,
          > Kenneth Grome
          > Bagacay Boatworks
          > www.bagacayboatworks.com
          >
          >
          >
          >
          >
          >
          >
          >
          > On Friday 16 February 2007 19:53, Sal's Dad wrote:
          > > Look at Twinkle
          http://www.boat-links.com/Atkinco/Utilities/Twinkle.html.
          > > "3 h.p. will be ample for speeds up to six miles an hour."
          >
        • pkj49cello
          ... Gas ... Many thanks for your thoughts. I see Kenneth s point about tunnel sterns requiring more power than an electric motor would want to provide. Maybe
          Message 4 of 15 , Feb 16, 2007
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            --- In AtkinBoats@yahoogroups.com, "Lewis E. Gordon"
            <l_gordon_nica@...> wrote:
            >
            > Twinkle is a nice design, but don't forget the weight of the batteries
            > you need to carry along. At 16 feet and flat bottomed it might be
            > difficult to get the batteries low enough to get be ultra "seaworthy".
            > Also at 16 feet, MotoSkiff, being V-bottomed might be a better choice.
            > While not a tunnel stern design, the draft is a modest 11 inches and
            > the propeller is well protected. And, she was designed for low power
            > and to be easily built.
            >
            > There is also Sixteen Too and Heron (tunnel sterned) at 17 feet and
            > not as easy to build. I used to boat off Brunswick County, NC and also
            > up in the Beaufort (NC) area. I can just imagine cruising along with
            > quiet electric power in MotoSkiff up the Lockwood Folly river and
            > seeing the alligators sunning and watching the ospreys fishing. It was
            > a very special area in the coastal Carolinas.
            >
            > Lewis,
            >
            > --- In AtkinBoats@yahoogroups.com, Ken Grome <bagacayboatworks@> wrote:
            > >
            > > Good recommendation Sal's Dad, I had forgotten all about Twinkle!
            > >
            > > I still don't think a tunnel hull is the ideal design for an
            > electric motor
            > > because it takes a lot of power to lift the water into the tunnel.
            Gas
            > > engines can easily produce this much power but electrics would
            > probably drain
            > > batteries fast in this effort.
            > >
            > > Then again for short distances an electric motor in a tunnel hull
            > like Twinkle
            > > might be just the thing, although I agree that this boat can
            > probably be
            > > built lighter and still be safe and plenty strong enough for its
            > intended use
            > > -- and lighter is often better when limited power is available.
            > >
            > > Sincerely,
            > > Kenneth Grome
            > > Bagacay Boatworks
            > > www.bagacayboatworks.com
            > >
            > >
            > >
            > >
            > >
            > >
            > >
            > >
            > > On Friday 16 February 2007 19:53, Sal's Dad wrote:
            > > > Look at Twinkle
            > http://www.boat-links.com/Atkinco/Utilities/Twinkle.html.
            > > > "3 h.p. will be ample for speeds up to six miles an hour."
            > >
            >



            Many thanks for your thoughts. I see Kenneth's point about tunnel
            sterns requiring more power than an electric motor would want to
            provide. Maybe my yen for a tunnel stern boat will have to wait till
            this present itch is scratched.

            May I give you all some more of my design wishes? Please bear with me
            and change channels if you need to.

            I spent three weeks in the ACE basin of coastal SC last spring. This
            is an area of marshes and creeks between Savannah GA and Charleston
            SC. It is mostly undeveloped, being protected by various Wildlife
            Management areas. It has strong tidal currents, some stretches of open
            water, but is mostly protected. The roughest conditions I encountered
            were in Charleston harbour, shortly after launching.
            The whole area is incredible for wildlife. One anchorage off the
            Edisto river, I had (at different times) alligators and dolphins
            swimming close to the boat.
            I was on my 23 ft trailer sailor, but due to the narrow channels,
            contrary winds and a boat (bless her heart), that doesn't tack worth a
            hoot, we spent 100% of time listening to the two stroke.

            So what I think I need, is a 25 foot, easilly driven, room for two,
            electric powered boat. I see using solar panels to power the batteries
            for short hops, and a generator to help out for the longer runs.
            Shallow draft would allow easy launches and access to distant creeks,
            while a flat bottom would allow me to dry out should I want to really
            explore. That is where the tunnel stern thought came from.

            I share Lewis's dream of silently cruising past all kinds of salty
            wildlife- really I suppose, sailing without the sails.

            Any thoughts?

            Doug
          • Bruce C. Dillahunty
            ... I ll agree with that... I drive a Prius :-) ... I agree up to a point... there are a couple of mitigating factors though. 1) You can operate the mechanical
            Message 5 of 15 , Feb 16, 2007
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              derbyrm wrote:
              > If you look at mpg figures for hybrid automobiles, it quickly becomes apparent that electric power is great for stop/go applications;
              I'll agree with that... I drive a Prius :-)
              > but not worth the effort for the sort of steady state effort that most boat propulsion systems are used in.
              >
              > Every time you convert from one form of energy to a different form, you lose a significant percentage to heating the atmosphere.
              > chemical => mechanical -- direct connection of gas engine to prop
              > vs
              > chemical => electrical => mechanical -- battery to motor to prop
              > vs
              > chemical => mechanical => electrical => mechanical -- driving electric motor with genset
              >
              I agree up to a point... there are a couple of mitigating factors though.

              1) You can operate the mechanical (gas/whatever) at its optimum
              efficiency instead of varying it to achieve other performance. This
              probably wouldn't outweight the inefficiencies, but would help offset
              them somewhat.

              2) You can use other energy sources (solar/wind/etc.) to supplement the
              gas... this is where the win is/is going to be in my opinion. I think in
              a few years we'll keep seeing solar drop in price and rise in
              effeciency. As I can get more power from the sun, I can rely on that gas
              engine less.

              Either way, its a neat technology :-)

              Bruce
              > Roger
              > derbyrm@...
              > http://home.insightbb.com/~derbyrm
              >
              >


              --
              Bruce Dillahunty
              bdillahu@...
              http://www.craftacraft.com
            • sals_dad
              First, check out the Yahoo Electricboats forum. Lots of intelligent discussion of electric propulsion. It has come a long way, but the limiting factor is
              Message 6 of 15 , Feb 17, 2007
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                First, check out the Yahoo Electricboats forum. Lots of intelligent
                discussion of electric propulsion. It has come a long way, but the
                limiting factor is still the very low capacity of lead-acid batteries
                (compared with, say, a gallon of gasoline)

                But for auxiliarry propulsion of a small sailboat, it might be just
                the thing.

                If I were you (and in fact I AM you - with a 21' sharpie that can't
                beat worth a d*&^, beautiful quiet shallow waters with strong
                currents...) I would (did) spend $300 at WalMart on a biggish Minn-
                Kota trolling motor and a couple biggish batteries, and start messing
                around. Add solar, generator, bigger batteries, etc as you think you
                need them.

                If you find the propulsion system meets your needs but your sailboat
                doesn't, THEN think about a new hull.

                Efficiency of electric? - as of today, it would be very difficult to
                assemble an electric system as efficient as you can get with gasoline -
                whether you measure efficiency in miles/dollar, miles/lb of
                mechanical and fuel carried, miles/lb carbon burnt, whatever - unless
                you can find a sweet spot of low usage, and high solar/wind charging.
                The big advantage of electric in boats is the quiet...

                Sal's Dad


                > I was on my 23 ft trailer sailor, but due to the narrow channels,
                > contrary winds and a boat (bless her heart), that doesn't tack worth
                a
                > hoot, we spent 100% of time listening to the two stroke.
                >
                > So what I think I need, is a 25 foot, easilly driven, room for two,
                > electric powered boat....
              • derbyrm
                Many years ago, the editor of Analog Science Fact & Fiction, mused on the several forms of efficiency: - miles per gallon - miles per dollar - watts per pound
                Message 7 of 15 , Feb 17, 2007
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                  Many years ago, the editor of Analog Science Fact & Fiction, mused on the several forms of efficiency:

                  - miles per gallon
                  - miles per dollar
                  - watts per pound
                  - watts per cubic foot
                  - watts per milligram of pollutants emitted at point of use
                  - watt-seconds per dollar of maintenance costs

                  People have suggested that we should use hydrogen fusion for power, like the sun does, but the sun's efficiency is something like one horsepower per cubic mile. (It's been a long time since I saw the actual figure.) Parking/docking such a vehicle would be difficult.

                  When we select a power system we unconsciously make a lot of choices on prejudice and then argue over some quantifiable thing like mpg. Sure, electric power is clean at point of use, but the total emissions for the system may be lousy; e.g. did the battery get charged by an old coal burning power plant? How long before the wind farms or solar cell arrays make a noticeable change in the weather? Land is about $10,000 per acre here in Southern Indiana, but up in the Chicago area, that money would buy only a few square feet. Electricity cost is primarily transmission cost, so don't talk about the square miles of desert out west.

                  I once spent several hobby years designing a modern steam car. Burns anything, as clean as you want to make it, full torque at zero rpm, quiet, and the Stanley Brothers built the best. (It failed for psychological and marketing reasons, not because it was bad technology.) An acquaintance pointed out that I'd never get my prototype to the level of comfort and convenience that a modern gas powered automobile offered, even with a superior power plant.

                  'tis a conundrum.

                  Roger (too old to start cutting metal now -- I've a boat to build)
                  derbyrm@...
                  http://home.insightbb.com/~derbyrm

                  ----- Original Message -----
                  From: Bruce C. Dillahunty
                  To: AtkinBoats@yahoogroups.com
                  Sent: Friday, February 16, 2007 10:07 PM
                  Subject: Re: [AtkinBoats] Re:electric drive for a tunnel stern?


                  derbyrm wrote:
                  > If you look at mpg figures for hybrid automobiles, it quickly becomes apparent that electric power is great for stop/go applications;
                  I'll agree with that... I drive a Prius :-)
                  > but not worth the effort for the sort of steady state effort that most boat propulsion systems are used in.
                  >
                  > Every time you convert from one form of energy to a different form, you lose a significant percentage to heating the atmosphere.
                  > chemical => mechanical -- direct connection of gas engine to prop
                  > vs
                  > chemical => electrical => mechanical -- battery to motor to prop
                  > vs
                  > chemical => mechanical => electrical => mechanical -- driving electric motor with genset
                  >
                  I agree up to a point... there are a couple of mitigating factors though.

                  1) You can operate the mechanical (gas/whatever) at its optimum
                  efficiency instead of varying it to achieve other performance. This
                  probably wouldn't outweight the inefficiencies, but would help offset
                  them somewhat.

                  2) You can use other energy sources (solar/wind/etc.) to supplement the
                  gas... this is where the win is/is going to be in my opinion. I think in
                  a few years we'll keep seeing solar drop in price and rise in
                  effeciency. As I can get more power from the sun, I can rely on that gas
                  engine less.

                  Either way, its a neat technology :-)

                  Bruce
                  > Roger
                  > derbyrm@...
                  > http://home.insightbb.com/~derbyrm
                  >
                  >

                  --
                  Bruce Dillahunty
                  bdillahu@...
                  http://www.craftacraft.com





                  [Non-text portions of this message have been removed]
                • donschultz8275
                  ... batteries ... You could build a Jim Michalak AF4G. 22 flattie skiff with a slot type slot type tunnel at lease 6x1 in proportion ahead of the transom.
                  Message 8 of 15 , Feb 17, 2007
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                    --- In AtkinBoats@yahoogroups.com, "pkj49cello" <Johnst1@...> wrote:
                    >
                    > So what I think I need, is a 25 foot, easilly driven, room for two,
                    > electric powered boat. I see using solar panels to power the
                    batteries
                    > for short hops, and a generator to help out for the longer runs.
                    > Shallow draft would allow easy launches and access to distant creeks,
                    > while a flat bottom would allow me to dry out should I want to really
                    > explore. That is where the tunnel stern thought came from.
                    >
                    > I share Lewis's dream of silently cruising past all kinds of salty
                    > wildlife- really I suppose, sailing without the sails.
                    >
                    > Any thoughts?
                    >
                    > Doug
                    >

                    You could build a Jim Michalak AF4G. 22' flattie skiff with a slot
                    type slot type tunnel at lease 6x1 in proportion ahead of the
                    transom. The motor well could hold the generator and gasoline, but
                    I'd put the batteries amidship.

                    http://www.duckworksbbs.com/plans/jim/af4/grande/index.htm

                    Michalak's Twister is another possibility but is only a 16'
                    motorsailor.

                    http://www.duckworksbbs.com/plans/jim/twister/index.htm

                    Checkout the simple tunnel design for this shallow water fishing
                    boat. This is what I suggest could be added to the AF4G.

                    http://www.bateau.com/proddetail.php?prod=XF20

                    Click the link then click on the 'study plan' link. Part way down
                    there is an excellent color drawing of the "tunnel"

                    Don Schultz
                  • Ken Grome
                    Hi Doug, Canoes and kayaks are so slim that they slice very easily through the water. Some of them can run all day on trolling motors before their batteries
                    Message 9 of 15 , Feb 17, 2007
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                      Hi Doug,

                      Canoes and kayaks are so slim that they slice very easily through the water.
                      Some of them can run all day on trolling motors before their batteries give
                      out. Maybe canoes or kayaks are what you really need for the type
                      of "exploration boating" you've described ...

                      Have you ever thought of using two boats? I like the ones shown in the links
                      below . How about building two of them so each of you can have your own
                      boat:

                      http://www.jemwatercraft.com/proddetail.php?prod=Muskoka
                      http://jemwatercraft.com/proddetail.php?prod=BucXW

                      These boats can handle 800+ pounds of people and gear each, for a total
                      capacity of more than 1600 pounds. That's a lot for two people! If it's too
                      much capacity you could always build two of this model for a total capacity
                      of 1000 pounds:

                      http://jemwatercraft.com/proddetail.php?prod=Buccaneer

                      You could put an electric trolling motor on any of these boats.

                      If I were doing your exploring I might put a trolling motor on each boat, then
                      bring along a very small (and quiet) 4-stroke outboard. Just put the
                      outboard on the front boat and tow the other boat on your long treks.

                      If you get an outboard with a charging circuit it would even recharge your
                      batteries for you!

                      Sincerely,
                      Kenneth Grome
                      Bagacay Boatworks
                      www.bagacayboatworks.com






                      > I spent three weeks in the ACE basin of coastal SC last spring. This
                      > is an area of marshes and creeks between Savannah GA and Charleston
                      > SC. It is mostly undeveloped, being protected by various Wildlife
                      > Management areas. It has strong tidal currents, some stretches of open
                      > water, but is mostly protected. The roughest conditions I encountered
                      > were in Charleston harbour, shortly after launching.
                      > The whole area is incredible for wildlife. One anchorage off the
                      > Edisto river, I had (at different times) alligators and dolphins
                      > swimming close to the boat.
                      > I was on my 23 ft trailer sailor, but due to the narrow channels,
                      > contrary winds and a boat (bless her heart), that doesn't tack worth a
                      > hoot, we spent 100% of time listening to the two stroke.
                      >
                      > So what I think I need, is a 25 foot, easilly driven, room for two,
                      > electric powered boat. I see using solar panels to power the batteries
                      > for short hops, and a generator to help out for the longer runs.
                      > Shallow draft would allow easy launches and access to distant creeks,
                      > while a flat bottom would allow me to dry out should I want to really
                      > explore. That is where the tunnel stern thought came from.
                      >
                      > I share Lewis's dream of silently cruising past all kinds of salty
                      > wildlife- really I suppose, sailing without the sails.
                      >
                      > Any thoughts?
                      >
                      > Doug
                    • Chris Partridge
                      ... anything, as clean as you want to make it, full torque at zero rpm, quiet, and the Stanley Brothers built the best. (It failed for psychological and
                      Message 10 of 15 , Feb 18, 2007
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                        >>>I once spent several hobby years designing a modern steam car. Burns
                        anything, as clean as you want to make it, full torque at zero rpm, quiet,
                        and the Stanley Brothers built the best. (It failed for psychological and
                        marketing reasons, not because it was bad technology.) An acquaintance
                        pointed out that I'd never get my prototype to the level of comfort and
                        convenience that a modern gas powered automobile offered, even with a
                        superior power plant.





                        The advantages you list, especially full torque at zero rpm, are just what
                        you need in a boat. How about designing a marine version?

                        Chris



                        [Non-text portions of this message have been removed]
                      • derbyrm
                        Actually, the marine application is quite different; little starting and stopping, relatively limited environmental temperature changes, greater need for
                        Message 11 of 15 , Feb 18, 2007
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                          Actually, the marine application is quite different; little starting and stopping, relatively limited environmental temperature changes, greater need for economy. Marine steam plants used quite exotic arrangements in the name of efficiency; compounding, feedwater heaters, economizers, ...

                          Everything I know about Stanley Steamers came from a wonderful little book: "The Story of a Stanley Steamer" by George Woodbury. He restored a 1917(?) model from terribly decrepit condition but was able to talk to original owners and mechanics.

                          Some gems I remember:

                          One of his initial test drives after years of restoration found him cruising down a country road. He glanced down at the speedometer and discovered he was doing seventy miles an hour on the forty year old wooden spoked wheels. He slowed gently but immediately. (A Stanley built steamer held the world's speed record for a long time -- 114 mph on the sands of Daytona Beach with really primitive suspension.)

                          His neighbors had a tennis court near his garage. One evening he came back from a ride, noticed the neighbor's wife about to serve, and, without thinking, tripped the boiler blow down valve. The serve went into the next county. (Railroad locomotives had mufflers on their blowdown valves to keep the neighbors happy.)

                          His wife took the car to town one afternoon. Fires in the boiler compartment were not significant and went out promptly, but someone had called the fire department. If they were allowed to dowse it, she would be stuck for an hour or so while she got pressure back up, so she fled town, streaming fire and smoke, and pursued by the fire truck with sirens and bell.

                          As I said, I'm too old to start cutting metal and ideas that look great on paper often turn out differently in practice.

                          Roger
                          derbyrm@...
                          http://home.insightbb.com/~derbyrm

                          ----- Original Message -----
                          From: Chris Partridge
                          To: AtkinBoats@yahoogroups.com
                          Sent: Sunday, February 18, 2007 9:19 AM
                          Subject: RE: [AtkinBoats] Re:electric drive for a tunnel stern?




                          >>>I once spent several hobby years designing a modern steam car. Burns anything, as clean as you want to make it, full torque at zero rpm, quiet, and the Stanley Brothers built the best. (It failed for psychological and marketing reasons, not because it was bad technology.) An acquaintance pointed out that I'd never get my prototype to the level of comfort and convenience that a modern gas powered automobile offered, even with a superior power plant.

                          The advantages you list, especially full torque at zero rpm, are just what you need in a boat. How about designing a marine version?

                          Chris
                          [Non-text portions of this message have been removed]
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