"Twilight" an electric boat

Discussion in 'Boat Design' started by g.maclaren, Jul 29, 2008.

  1. Boston

    Boston Previous Member

    I also like the concept
    30" seems a bit narrow to me to
    Ive had canoes wider than that
    and spent my share of time swimming
    although with a hydrodynamic ballast box for the batteries
    you will gain some stability
    does it have to be a mono hull
    a simple outrigger would solve some of your stability problems
    might keep a late night moment of affection
    from turning into a late night swimming lesson
    :)


    (
     
  2. g.maclaren
    Joined: Jul 2008
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    g.maclaren Retired Expert

    Rick,
    I do like the FT idea, but can't imagine it being built by me.
    I'm too impatient and don't really enjoy the building.
    (If I could buy a boat to fill my "needs" (desires?), I would.

    I also like the idea of making the center section larger and adding
    two sealed end sections. That get the "dividing line" out of
    the cockpit and might make the two end sections easy to build.

    I am not al all concerned about using the Minn Kota trolling
    motor, esp. with larger capacity batteries. The old motor first
    used in my little green
    boat has had powered cruises of 1.5 hours and when I return to
    the pier, the charger does its job. The 12 v. battery is
    a car battery. So with better/more batteries and the more
    efficient Minn Kota, electric power is no problem in this
    application.

    From what I've read, golf carts use 6 v. batteries, so I'll
    get two of them and hook them up in series. With the Minn-Kota
    40# thrust motor supplied by two deep cycle golf cart batteries,
    the power and drive problems are solved.

    I might consider steering with a rudder, but that's another issue.
    I managed to break the vertical shaft of the trolling motor BUT
    that's because I was using the boat in a shallow lake -- not in the
    water for which Twilight is/will be designed and will be used.

    My big problem is hull shape. I want keep the batteries low.
    I want to sit with "feet on the floor."
    I want the boat to look kinda elegant -- reminding one of a
    late 1800's or early 1900's launch.
    I think low freeboard and plumb stem and stern and double-
    ended hull satisfies this. The decks do, too -- and may be
    useful if a wakeboarder is on the lake at dusk.

    Transportation is not really a problem. I have a boat trailer for
    my Four Winns I/O and it could be used to get TWILIGHT to the
    lake for long (1 to 2 week) stays. Having a 20 ft. long hull to store
    is a bit of a problem. But even if it didn't come apart, I could
    deal with storage, too. If I decide to leave Twinkle at the lake,
    having it come apart in sections of less than 10 ft. would be
    helpful.

    I'll continue to think about the original concept (folding in
    middle) but am now leaning toward a larger center section with
    comfortable cockpit and the two end sections added for a longer
    hull and associated aesthetics.

    I am not too concerned about stability, but would like the boat
    to float nicely with no passengers aboard, ie, moored at the pier
    between cruises. But even this is not an absolute requirement.
    I can pull the boat onto the pier, leaving the motor and prop
    hanging off the end of the pier.

    -=Grant=-
     
    Last edited: Aug 1, 2008
  3. g.maclaren
    Joined: Jul 2008
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    g.maclaren Retired Expert

    "I can always pull the boat onto the pier."

    "I can always pull the boat onto the pier."
    This shows the little green boat with its motor pulled onto the pier a few weeks ago when the water was very high and the lake was under a "no wake" order.
    -=Grant=-
     

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  4. g.maclaren
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    g.maclaren Retired Expert

    Maybe I should just order one of these:

    Maybe I should just order one of these:

    http://www.ElectricCanoe.co.uk/pictures.htm

    (His motor mount look just like mine.)

    Seriously, Twilight should be a boat used much like
    I'm sure this one is used. So, can a simple, cheap
    version of this canoe be made that meets my desires?

    I'd rather have something that looks less canoe-like
     

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  5. Tiny Turnip
    Joined: Mar 2008
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    Location: Huddersfield, UK

    Tiny Turnip Senior Member

    Hi Grant

    I've posted a picture and link of Swallow boats 'Winsome' on the pedal powered boat thread here. Post 61 I think. While a different power source, and not quite as skinny as you are proposing, It might capture a little of the ethos of your concept?
     

    Attached Files:

  6. Guest625101138

    Guest625101138 Previous Member

    Grant
    I don't think you would find building the FT too difficult. It might make sense to keep the centre section within a length suited to ply. If you can stitch and glue it would not be too difficult. It is possible to make cutting plans from the hull design I have. If you can fit two seats and table in the middle section at 8ft then the two ends become 5ft each.

    The long central hull is 16" wide as the maximum so would be fine for standing in. With the outriggers as shown I would expect you could stand on the sides as well.

    The boat will sit flat in the water with the two batteries stowed.

    I would be looking at setting the drive up beside the rear seat hanging down off the wing. This way it only needs to be deep enough to get the prop under water. Have offset propulsion on a long slender hull like this does not reduce performance in a measurable way. I think it could also be used for steering from this position.

    The actual shape of the hull is not super critical. It is very simple so would only take a few hours to mock up in cardboard so you get an idea of what it looks like.

    Rick W.
     
  7. g.maclaren
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    g.maclaren Retired Expert

    Hi Tiny,

    That is does. I visited their website

    http://www.swallowboats.co.uk/content/view/94/104/

    and found it also uses water ballast to trim for light, or no second person aboard.

    Nice.
    Thanks,
    -=Grant=-
     
  8. g.maclaren
    Joined: Jul 2008
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    g.maclaren Retired Expert

    Rick,
    Just returned from a 2 hour cruise on a small local lake. As usual, there was much interest shown in the little green boat.
    The motor worked fine and I did not hit any stumps, etc. -- so brought it back in one piece.
    I had just about decided to make a model of a most simple hull shape (I'll make a sketch and post it here within 24 hours.) but have decided to first try to model the FT hull you posted as a pdf.
    I'll try using luan ply, 1/4 scale.
    Maybe before I start cutting wood, I'll post sketches of the components.
    Do you think there is a way to "hide" the shape of the boat in plan view?
    To make it look more "old timey?"
    I'm also going to post a new page (tonight) at www.grantmaclaren.com/twilight

    -=Grant=-

    PS -- The two images here show the first model with waterproof seams.
     

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  9. g.maclaren
    Joined: Jul 2008
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    g.maclaren Retired Expert

    Rick,
    Could the beam of the FT's main hull be 20 inches?

    I think it be more suitable to my building skills to
    just make it a real "tri" and have the small hulls
    be supported by (round or square) aluminum tube.

    Width of passenger's bodies would have room within
    a 20 inch beam and I would not have to build those
    beams with their intersecting curves. I'd make a mess of
    that, methinks.

    There could also be a "table" supporting the small
    hulls. I've tried to show that in a sketch below.

    The monohull idea came to me while cruising
    this evening. The dimensions are more suitable
    to ply sizes and the sloped "transoms" might be
    extended as seat backs. Eight feet would give
    plenty of room for two. The box keel is shallow,
    so batteries would be in the center of the center
    section and the passengers would have to sit
    lower than I would like.
     

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  10. Guest625101138

    Guest625101138 Previous Member

    Grant
    I have tried to make it look more conventional. The various images will hopefully give you a better idea of how it goes together.

    The colour scheme is to distinguish pieces. The main hull and seating pieces would be maybe 7mm ply. The deck and outriggers would be 4mm ply. You would need some bulkheads and some trim to get the shape and stiffen it up.

    I expect it would be quite heavy. Say 100 to 120lb. I would need to do more detail to get it more accurate.

    If I get time over the weekend I will look at the box keel.

    Rick W
     

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  11. Guest625101138

    Guest625101138 Previous Member

    Grant
    Here is the box keel version.

    Its initial stability is a bit twitchy but it stiffens up quickly so I doubt that it would roll easily. I have not done a stability check but with 120lb of batteries low down it will be stable enough.

    It has similar performance to the wider canoe having the same beam, which is about 0.5kt slower for the same power than the FT.

    Obviously this is quite simple to build. If it is going to be in parts I would still suggest a middle with two ends.

    There is a variant of the box keel that I have called FT2. I have raised the floor to be almost clear of the water. It means just the chine submerges so it is similar to the FT. It performance is almost as good as the FT.

    Rick
     

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  12. kengrome
    Joined: Jul 2006
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    Location: Gulf Coast USA

    kengrome Senior Member

    Grant, this doesn't look like the launch you mentioned above, but it looks good to me nevertheless -- and it has an excellent box keel and is human-powered which makes it ideal for repowering with a trolling motor and a couple batteries:

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

    [​IMG]

    The plans are only $52 and it's design makes it an exceptionally strong and stable boat with that box keel bottom and built-in 'sponsons'. This one is 32 inches wide. The designer has a larger version too in case you think this one's not big enough.:

    http://www.jemwatercraft.com/StudyPlans/BuccaneerXW16StudyPlans.htm

    [​IMG]

    Obviously the interior would be of your own design, but these hulls are virtually guaranteed to be strong and stable, and they come from a well known designer of human powered boats -- just like Rick only different!
     
  13. g.maclaren
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    Location: Ballwin, Missouri, USA

    g.maclaren Retired Expert

  14. g.maclaren
    Joined: Jul 2008
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    Location: Ballwin, Missouri, USA

    g.maclaren Retired Expert

    Autocanoe to be electric soon?

    Rick (and others),
    Did you notice on the website mentioned in "I want one of these" post that the designer says his electric powered version is coming soon?
    See
    http://www.autocanoe.com/
    -=Grant=-
     

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  15. g.maclaren
    Joined: Jul 2008
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    g.maclaren Retired Expert

    Another photo

    Only to keep this thread alive, I am posting a recent photo of my 1/4 scale model in water, loaded with rocks.
    I'm trying to develop a quick and easy waterproof joint in luan ply and think I've found a solution. It uses the paper tape used in adding machines and Titebond III glue, then house paint.
    More to come soon.
    Please stay tuned.
    Busy with other project right now.
    -=Grant=-
     

    Attached Files:

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