Complicated And High Cost?

Discussion in 'Hybrid' started by SURV69, Apr 22, 2010.

  1. SURV69
    Joined: Apr 2010
    Posts: 7
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    SURV69 Junior Member

    When my 10hp motor was stolen off my 25 foot sailboat(2500 pounds)12 years ago, I bought a 42 pound thrust MinnKota to use until I would get another outboard motor.

    I never bothered with getting a new outboard motor . . . well, I kinda lied. I bought a 6HP motor, but gave it to a guy who needed a motor. I never used it.

    ANYWAY, the 42 pound thrust motor with a "fishing" type propeller, along with an unusable car battery, got me through the next few years.

    The power was enough to get in and out of dock and even to point to wind. If I was off wind, the thrust was enough to get me back into the wind.

    I once(after pulling out only to realize I had no main-sheet), even used the electric motor at it's slowest speed to get back to dock(about 4-5 miles), on this worthless battery.

    Simplicity at it's simplest.

    Now there are special made propellers for trolling motors(Kipawa), that substantially increases a trolling motors thrust. Something I never had before.

    Now I own a 26' sailboat(dispacement of 4000), and I hope to go electric.

    I have gone all over the internet and have seen all kinds of systems.

    One(really three), things have remained constant with electric motors). High cost, complicated computations for range and fear).

    Electric motors are so simple compared to IC engines and yet the costs for small-boat conversions are so reltively high, plus adding the batteries increase the cost even more. The high battery costs, I understand, but the costs of the motors(and mounts), what gives? I kinda wonder if it's a yuppie-type thing and anything ecological is expected to cost more, even if it shouldn't.

    Everyone goes through the complication of comparing electric motors to IC engines in terms of HP. I've never figured what HP is really all about(for a sailboat). If I put a 5HP engine on my 26' sailboat, it's no different than a 15HP engine on my 26' sailboat, or for that matter, a 50HP engine. The boat can basically be expected to go X speed(which is admittedly slow), and that speed is accomplished without the OB engine even approaching the RPM's that are directly related to rated HP. That "10HP" engine is still "10HP", whether it's running slow on a sailboat or fast on a fishing boat. Except, that at the slower speed of a sailboat, that "10" means almost nothing.

    At most times, the sailboat needs to move at a leisureley speed, not a "fast" speed. I've often thought 2-3 knots as being near top-speed needed for adequate motoring. If one needs faster speeds, then one should really look into a power boat.

    Of all the sailors I know(I dock at a "sailboat" marina), the largest concern is the remaining fuel at the end of the year or even worrying about the "second" year's fuel and whether to "recycle" it somehow. I only know of 1 sailor(maybe a second too), that has ever had to refuel during the boating season. Oh yeah, forgot, a very large sailboat has to refuel a couple of times during the season, but this boat runs a number daily charters and sunset trips . . . on a schedule.

    I have been on many sailboats and I have rarely seen the motors turned on in favor of sailing, except when a storm's coming up . . . AND, what's with that?

    I have yet to see a motoring sailboat outrun a storm that's coming, so the only advantage to motoring is the fact that sails are down. This seems like an issue that needs to be addressed by education of how to reef properly to sail through a storm(at least from time to time), or weather-watching and not going out when a storm's apporoaching.

    Otherwise, the only time a motor is started is leaving a dock, getting into the lake, running into the wind to hoist the mainsail, then returning to the dock. One half hour or so of motoring, maybe, once a week, tops.

    In fact, most sailboats spend much more time at dock, than away from the dock. Often the only time they move is to go to the clean-out station. For the most part, they don't need a motor at all and for that matter, I prefer the well-lit restrooms with showers . . . forget the clean-out.

    I'm not ranting as much as I'm asking, why isn't going electric much "simpler" and "cheaper"? Especially so, for smaller sailboats that don't need much to move them?

    Why is it that the worst-case scenerio, is always the "expected" scenerio, when we compare gas to electric?

    AND . . . why is the electrical need always determined based on the fastest possible hull-speed, when virtually no one goes hull-speed, except under sail?

    In short, why is going electric so complicated and costly?

    For me, a MinnKota, (55 to 70 pound thrust), with a Kipawa propeller, 4 or more deep-cycle batteries and a good charger(to plug in at the dock), is where I'm going to start.

    Beyond this, I'll operate my boat like a sailboat and not a poorly designed powerboat.

    I'm sure that I'm 100% all wrong, but this IS what I'm going to do and I'll let everyone know if it worked or didn't.

    I think everything will be just fine.
  2. Stumble
    Joined: Oct 2008
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    Location: New Orleans

    Stumble Senior Member


    I actually did this on my sailboat last year (Olson 30 abt 3600lbs). I used a 55 Minn-Kota 55 12V and my small house battery to get me in and out of the harbor. Now I can tell you it did work on a nice calm quite day, but if I tried to motor into any headwind, chop, or current the boat came to a stop. Max speed was about 2.5kn on a dead calm day with water like glass.

    So if this works for you then go for it, my problem really came down to not being able to get out of my harbor in the event of a head wind, so I went back to a small gass engine.
  3. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    SURV69, your reasoning is basically sound.
    Electric propulsion is still rare and therefore expensive. That may soon change when automotive components come available and production quantities drastically increase.

    The limited range problem can be solved by adding a small genset and a can of fuel to your system. I have an old Italian unit that even your wife can carry around with one hand, capable of delivering 25A to charge your battery.
  4. SURV69
    Joined: Apr 2010
    Posts: 7
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    SURV69 Junior Member

    Success ?

    I placed a MinnKota 24 volt 80 pound thrust motor on my Pearson 26 with 2 size 29 batteries.

    Deep sixed my 9.9 4-stroke Suzuki and replaced the prop with a Kipawa propeller.

    The boat travels faster than I generally like to go. The next time out I'll use the GPS for some figures. It appeared to run about 4 knots upriver.

    Generally speaking the motor will only go to about 3/4 speed. Beyond that speed the propeller begins to "slip"(early stage of cavitation?) and at near full-throttle the propeller cavitates.

    At 24 volts the motor draws 0.75 amps per pound, so it's probably drawing about 40-50 amps. I expect to operate at about 1/4 throttle or less except in certain cases. My 2-12 volts(24 volt) batteries have about 125 amp hours. Hopefully someone here can tell me if the 125 amp hours is the number of amp-hours to the 40% discharge or if it's to a 100% discharge.

    ANYWAY I personally don't believe the transition to electric should be such a costly endeavor . . . except, maybe, for larger sailboats(I have a Pearson 26). This, along with the earlier results of my 27 lb thrust motor on my old MacGregor 25 seems to agree with my belief . . . within reason.

    The motor costs $400(refurbished from Cabelas), along with the Kipawa propeller($40) and two wet-cell size 29 batteries from WalMart($85 each). I'm expecting to buy at least two more batteries.

    Too bad about the cavitation above 3/4 throttle.
  5. BTPost
    Joined: Dec 2009
    Posts: 47
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    Location: Excursion Inlet, Alaska

    BTPost Junior Member

    I am with CDK on this one, a nice SMALL/Quiet Honda Inverter Genset, and a 5 USG Gas-tank to power a 120Vac to 24 Vdc Charger/Power Supply, to get you in and out of Dock, is a nice way to go, and easily stored or fitted aboard. It also gives you some power for tools, etc, while away from the Dock, should that be necessary. What do you do for Running Lights? Whale Oil?
  6. Landlubber
    Joined: Jun 2007
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    Location: Brisbane

    Landlubber Senior Member

    ....OMG....Whale Oil.....don't tell the greenies mate, you will be harpooned.......use vegetable oil only, (unless of course you are a vegan, then it would be mineral oil)....oh ****, I am in trouble again....why not just use battery lights and then no one cares.....

  7. SURV69
    Joined: Apr 2010
    Posts: 7
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    SURV69 Junior Member

    LED lights with a dedicated & 2 very small 12 volt batteries(2 amp-hours each)

    The batteries are cam-corder batteries and measure 3/4" X 2" X 4", can be placed virtually anywhere and can easily be charged with a separate 5 watt solar panel.

    I also use puck LED's along with some bright strip-light LED's that run for days on a near-dead battery.

    If I conserve all my other uses for batteries, then virtually all my battery power can be used for the motor.
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