electric powered slipper?

Discussion in 'Boat Design' started by matt76, Aug 18, 2014.

  1. matt76
    Joined: Jun 2007
    Posts: 33
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: st. louis missouri

    matt76 Junior Member

    I am extremely interested in building an electric powered slipper launch. Much like these:
    http://www.peterfreebody.com/freebody-slipper-at-a-glance.php

    How ever I do have some extremely novice questions about modifying the design a bit. I'm looking for a really low profile boat. much like a bass boat but i need a hull design efficient enough for electric motors. I do not know the correct terms to use here, i apologize, bare with me. If you can see the second picture in the link above you'll see a good side view of the boat. Basically is it possible to build a boat like this with the deck just a foot or so from the water line? I'm not sure how to explain it any better, im sorry.
     
  2. gonzo
    Joined: Aug 2002
    Posts: 13,342
    Likes: 325, Points: 93, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    Considering the basic nature of your questions and the design you are referring to, buying a set of plans is your best option. Also, the shipwrights producing those boats are some of the world's top craftsmen. It will take you a couple of decades of effort to be at their level. The upholstery itself is a trade that can take half a lifetime to master.
     
  3. messabout
    Joined: Jan 2006
    Posts: 2,933
    Likes: 172, Points: 63, Legacy Rep: 1279
    Location: Lakeland Fl USA

    messabout Senior Member

    Clarify what you have in mind with the term"electric boat". You can have an electric boat with 100kw of power or less than 1kw of power. They would be much different boats. The gorgeous gentleman's runabouts in your pictures will need big power. Probably not practical as an electric boat. If you want a quiet, efficient, slow boat, then you can get by with precious little power. The opposite boat designs would be very different.

    Tell us what you want the boat to do and how and where it will be used.
     
  4. matt76
    Joined: Jun 2007
    Posts: 33
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: st. louis missouri

    matt76 Junior Member

    This boat would only be used on small lakes that don't allow gas engines. Mostly used as a day boat and fishing boat. would need to carry 500 lbs of batteries, two passengers. cockpit only needs to be big enough for two seats, the rest of the deck i would like to be flat and able to walk the entire deck. 72-96 volt inboard motor, agni motors are impressive, elco, master volt, vetus, asmo. I would like to keep her under 20 foot.
     
  5. Clarkey
    Joined: Aug 2010
    Posts: 101
    Likes: 6, Points: 18, Legacy Rep: 10
    Location: UK

    Clarkey Senior Member

    The Slipper launches in the photos don't have much power - no point really, the speed limit on the Thames (their native habitat) is 5mph.

    ETA: A typical engine would be something like a Morris 'Vedette' - between 6 and 12hp, giving a maximum speed of about 12mph where permitted.

    Selway Fisher Design have some plans for small slipper launches, including some for electric power.
     
  6. gonzo
    Joined: Aug 2002
    Posts: 13,342
    Likes: 325, Points: 93, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    If you have over 48 volts, lt is considered high voltage and a lot of extra regulations come into play.
     
  7. Willallison
    Joined: Oct 2001
    Posts: 3,590
    Likes: 129, Points: 0, Legacy Rep: 2369
    Location: Australia

    Willallison Senior Member

    I recently completed the design for an electric launch which, whilst somewhat different to what you describe in character is a demonstration that the basic concept of an all-electric slow-running boat is a viable proposition. Nothing terribly new there... I'm certainly not the only one to have done so.
    The boat in the attached pic is powered by a Mastervolt motor and is fed (I think off the top of my head) by 450kWh of batteries, which are in turn supplemented by a thin-film solar array mounted on the hardtop. She will potter along all day at around 3-5 knots quite happily.

    Doing the same thing with a slipper-style launch is definitely doable - though you would lose the added charge afforded by the solar panels (unless they were incorporated into the deck).
    Modifying the topsides is no real problem in and of itself, but is there a reason why you want such low freeboard?
     

    Attached Files:

    • 221.JPG
      221.JPG
      File size:
      976.1 KB
      Views:
      184
    • 147.JPG
      147.JPG
      File size:
      1.1 MB
      Views:
      593
  8. portacruise
    Joined: Jun 2009
    Posts: 1,048
    Likes: 20, Points: 38, Legacy Rep: 218
    Location: USA

    portacruise Senior Member

    "Nothing terribly new there"
    What has changed in the seven years since the original post? Lower cost of lithium batteries? Is that enough to get a reasonable speed/range even on a small lake for a sporty boat? If a Tesla car power setup could be put into a boat, would it make much difference in performance and range?

    PC


     
  9. fredrosse
    Joined: Jan 2005
    Posts: 324
    Likes: 16, Points: 28, Legacy Rep: 56
    Location: Philadelphia PA

    fredrosse USACE Steam

    Easy Electric Boat

    A possible option, at a cost much lower than a new build, which might fit your criteria. Convert a used fiberglass sailboat hull into a small electric cruiser. These boats are very inexpensive if found with bad sails or a broken mast, and there are plenty of these.

    The attached picture shows an O'day Javelin (14 foot sailboat) which I purchased on e-bay, with trailer, for $107 US, and converted to 24 volt inboard electric drive.

    For a total input of about 100 hours work, plus less than $1000 (including new tires, bearings and lights for the trailer) I was able to have a nice simple electric boat that cruises for about 4 hours carrying 4 adults at about 5MPH, or 20 hours at half speed.

    A complete description of the build is on the Yahoo electric boat site.
     

    Attached Files:

  10. fredrosse
    Joined: Jan 2005
    Posts: 324
    Likes: 16, Points: 28, Legacy Rep: 56
    Location: Philadelphia PA

    fredrosse USACE Steam

    Electric Javelin Build Details

    A description of the Electric Javelin Build, with all relevant details. I have used this boat for years without trouble.

    One good feature is the simple 12/24 volt electric setup. A simple switch puts the two deep cycle marine batteries in series for 24 volts, in parallel for 12 volts. Another switch gives forward or reverse rotation. For a simple cruising boat of this type, two forward and two reverse speeds are very adequate, and far far less expensive than electronic speed controls that cost plenty.

    I usually just run at full speed since several hours cruising are available. At low speed the boat can run for more than 20 hours, allowing easy exploration of the lakes and rivers, or slow speed trolling while fishing.
     

    Attached Files:

  11. portacruise
    Joined: Jun 2009
    Posts: 1,048
    Likes: 20, Points: 38, Legacy Rep: 218
    Location: USA

    portacruise Senior Member

    Yep, I've also used a heavy duty DPDT switch for series/ parallel and 2 speed control. It is old tech and works well at low speeds, also 100% efficient/ more reliable compared to electronic speed controls. Downside is that it is hard to hover if you need that capability, since you would have to constantly toggle between the 3 speeds- 0%, 50%, 100%...

    Porta

     
  12. TomCat58
    Joined: Dec 2013
    Posts: 12
    Likes: 1, Points: 0, Legacy Rep: 14
    Location: Washington State

    TomCat58 Junior Member

    I am working on a solar electric boat and I hope you can share a few things.

    1. Approx. How many amps do you use/draw at your 3-5 knots on smooth water with 0-5 winds ?

    2. How many solar panels do you have on top and how many amps can they produce with full sun directly over head ?

    3. What brand and model solar controller are you using ?

    Thank you in advance for sharing... I would like to get my boat built the best I can with limited funds. Others success and failures are very valuable info.

    TomCat
    PS Nice boat. A very nice boat :)
     
  13. fredrosse
    Joined: Jan 2005
    Posts: 324
    Likes: 16, Points: 28, Legacy Rep: 56
    Location: Philadelphia PA

    fredrosse USACE Steam

    450 kWh

    I believe there is a typo in the description.

    A lead-acid battery with a capacity of one kilowatt-hour has a weight of more than 50 pounds. Therefore 450 kWh battery capacity comes to the weight of about 450 large (Group 27) automotive starting batteries, with a weight of 22,500 pounds, slightly more than 10 long tons.

    I doubt that the nice little cruiser shown in the picture has such a displacement!
     

  14. gonzo
    Joined: Aug 2002
    Posts: 13,342
    Likes: 325, Points: 93, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    I think it is sales hype rather than a typo. But then, I am a cynic.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.