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mehitabel's motor system

  • 26 Dec 2012 10:06
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    Reply # 1166801 on 1152590
    Anonymous member (Administrator)

                                                                   Stavanger, Wednesday

    Jeff, I agree so much with Annie. After all, the distances you will cover will be moderate in the lake that your boat sits now, so pollution and fuel costs will be negligible compared to that of your car. Besides, I warn against fighting on two fronts: Your rigging and sailmaking project will keep you plenty occupied for a while. As for the engine, I would just change oil, oil filter and fuel filter and fit a big, new starting battery for the next season to ensure quick start and trouble-free running (or is the Yanmar already defect?).

    My friend Victor fell in the two-front trap. He bought a 31-footer a couple of years ago. When motoring the few miles home, the engine wasn’t happy. Although the fault could be traced to filthy diesel, he chucked out the whole engine and started a big experimental project with electric propulsion. The result is that his boat has been a berth queen since then. Neither the new JR nor engine system is operational yet (but hopefully this spring).

    Arne
  • 26 Dec 2012 05:23
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    Reply # 1166743 on 1152590
    Anonymous member
    Er, Jeff, have you ever heard of KISS?  Seablossom, after all, is a sailing boat.
  • 25 Dec 2012 20:42
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    Reply # 1166645 on 1152590
    Deleted user
    Here's a thought:  Seablossom's wimpy 7 1/2 hp Yanmar connects to a long propeller shaft that runs visible through a sump in the aft cabin.  Why couldn't one install an electric motor similar to Mehitabel's system, mounted in the sump (or maybe slightly above it depending on space available) and drive the propeller shaft via a pulley?  Perhaps use an electric clutch like a car air conditioner or similar device, but leaving that complication aside for a moment, have a setup where one could travel via electric power most of the time with the diesel transmission in neutral, but still have the option of firing up the diesel, engaging gear, and powering away.  Perhaps even run the electric along with the diesel for an extra boost in times of emergency - heaven knows the tiny Yanmar is none too powerful for a couple tons of Seablossom.
  • 25 Dec 2012 15:05
    Quote
    Reply # 1166588 on 1166502
    Deleted user
    Paul Thompson wrote:
    Jeff McFadden wrote:Here is a link to the ultimate solution.  Unfortunately I'm afraid it's a "just add money and stir" recipe.

    Edit: I've been snooping on their site, and they offer a 2 cylinder version of this system rated at 36 hp, which would be way too much for Seablossom's potential hull speed... oh my.

    Edit 2:  I couldn't help myself.  I wrote to a dealer asking for pricing.  That'll learn me, I'm afraid.  :'{

    It'll probably cost more than your boat!
    I bet you're right!  Still couldn't help asking.
  • 25 Dec 2012 05:46
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    Reply # 1166502 on 1166493
    Anonymous member
    Jeff McFadden wrote:Here is a link to the ultimate solution.  Unfortunately I'm afraid it's a "just add money and stir" recipe.

    Edit: I've been snooping on their site, and they offer a 2 cylinder version of this system rated at 36 hp, which would be way too much for Seablossom's potential hull speed... oh my.

    Edit 2:  I couldn't help myself.  I wrote to a dealer asking for pricing.  That'll learn me, I'm afraid.  :'{

    It'll probably cost more than your boat!
  • 25 Dec 2012 03:55
    Quote
    Reply # 1166493 on 1152590
    Deleted user
    Here is a link to the ultimate solution.  Unfortunately I'm afraid it's a "just add money and stir" recipe.

    Edit: I've been snooping on their site, and they offer a 2 cylinder version of this system rated at 36 hp, which would be way too much for Seablossom's potential hull speed... oh my.

    Edit 2:  I couldn't help myself.  I wrote to a dealer asking for pricing.  That'll learn me, I'm afraid.  :'{
    Last modified: 25 Dec 2012 04:57 | Deleted user
  • 24 Dec 2012 22:11
    Quote
    Reply # 1166437 on 1166389
    Anonymous member
    John Cornicelli wrote:... and we dropped the solar panel in the Potomac

    Oh dear.  I bet that spoilt a good day's sail!
  • 24 Dec 2012 19:30
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    Reply # 1166389 on 1155974
    Deleted user
    Kurt Jon Ulmer wrote:Hi John,

    Fun isn't it? Any smoke yet? I'd be glad to see your boat's propulsion numbers. 

    If you post the data here, some others will probably be interested too. Have you wrestled with how much compromise you'll accept, relative to a large-tank diesel?

    I've always admired the Gazelle. They have a real scenic charm to them.

    Best of luck,
    Kurt

    -----------------
    Hi Bertrand,

    Your system seems like the best of all worlds, and powerful. Beyond our means, for sure. 

    It's great that you can retain the working characteristics of a diesel system, but still lie at anchor and soak up fuel into the batteries. And are those 4 x 240W solar panels you have? Oh yeah, a 46' cat... I guess there's room. 

    Cheers,
    Kurt

    Heya Kurt,

    You asked the same question we wrestled with:  compromise.  And YES it has been FUN!   The yachties at the marina here already think we are insane with a junk, so messing with electrics was par for the course. 

    Since we did not have the resources available to do calculations based on a similar boat, we went from first principles and made some assumptions.  

    For instance, we knew the old Sabb diesel did a decent job and it was around 29 hp.  We are keeping the controllable pitch prop and its transmission, so we are expecting some loss there.  We'll just wing it with the CPP.

    So we calculated from a hullspeed of 7.7kts and then looked at what equivalent hp electric motors would give us what speed, to then calculate range in "runtime at speed X". We then looked at range with different battery arrays and the Amp-hours they provide....  


    So we got the following:
    Speed hp equivalent range example with two 48volt arrays (approx)
    7.7kts 35hp 1 hour
    6kts 17hp 2 hours
    5kts 10hp 3.8 hours
    4kts 5hp 6 hours
    3kts 2hp 12+

    Special case:  Forklift battery, 849Ah: 11 hours at 4 kts

    As soon as I figure out the "Box" account, I will post our spreadsheet.  I swear it feels like I am missing something and would love any opinions on the subject and our work up to now.  

    Project after this:  calculate charge rate vs. discharge rate at different speeds if we carry a 2000W Honda generator on-board as a backup range extender.  The wind generator will not cut it at 48V (does a good job on the 12V house batteries) and we dropped the solar panel in the Potomac

    Thanks!! 
    John C.
  • 13 Dec 2012 07:48
    Quote
    Reply # 1158899 on 1152590
    Anonymous member
    Yes Robert,

    The higher voltages used for electric motors do have more sparking potential, and with heaps of current available, the sparks are hot. More care is required than with a typical 12V boat system. 

    I don't like sparks. I cringe when I swing the big 48V 450A fuse into place. Usually, nothing happens.

    Batteries. It probably makes sense to research more than I did, and maybe to spend more money on batteries, if that's possible. The way of the future...

    Cheers,
    Kurt
  • 12 Dec 2012 16:22
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    Reply # 1158239 on 1152590
    Anonymous member
          When I worked in some factories my job was to look after battery fork lift trucks . such as topping up the batterys and control gear .   The Motors brush type, quite tough, plus the batterys , Im surprised nobody has tried to use the same in a boat .  the drawbacks might be , gassing of the batterys and keeping water out of the brushes on the motor .The units have been pushed to the utmost limits and come in different sizes , you probably need a charging unit  ,petrol , diesel , or shore ,wind or shine .   But be aware those batterys can pack a punch , ie loose connections ,or shorting out , think of a big welder in action .  Well just a thought .      
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

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