Experimental electric - opinions, please.

Discussion in 'Boat Design' started by tinhorn, Sep 15, 2014.

  1. tinhorn
    Joined: Jan 2008
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    Location: Massachusetts South Shore.

    tinhorn Senior Member

    Would you guys mind passing judgement on my project? We baptised it last weekend and I don’t know if I’m trying to polish a turd or if this little boat actually has potential.

    Background

    I bought it when I lived in high desert country, no water, no boating background. I also bought the hull molds in preparation for moving to a region with lots of water around. It’s the first power boat I’ve owned—my other boats are rowed, paddled, or pedaled.

    I have no idea who designed or whether they knew what they were doing. (Still don’t.) Some design aspects seem quite clever—others seem pretty shade-tree. It was in pieces when I bought it, but enough components were there to reverse engineer the project. The guy I bought it from knew nothing about it.

    The Boat

    Total loaded weight about 500 pounds. Length is 8 feet, width at the wingtips is 4 feet 8 inches.

    Power is a 36# thrust Minn Kota trolling motor, group 29 battery (both purchased used). Uses the standard controls. Prop is a 10” Kipawa three-blade with model airplane spinner, mounted 1.5” below the hull.

    Motor angle was guesswork. I had no idea what the boat’s attitude would be, nor the optimal motor angle.

    Performance

    Setting 1- .9 knots drawing 6 amps
    Setting 3- 1.7 knots drawing 12 amps
    Setting 4- 2 knots drawing 14.9 amps
    Setting 5- 2.8 knots drawing 33 amps

    Steering was horrible--much skidding. Surprised me since the white chase dinghy corners like it’s on a track.

    Dilemmas

    Please let me know if you think the attitude looks reasonable for what this boat is.

    I was disappointed by the speed. I hoped for about twice the speed I’m getting. In the last half of the video you can see the chase boat overtaking the subject boat. Both used Minn Kotas and were at the same speed setting. BUT the chase boat has a curvaceous bottom and uses a 45# thrust motor. Which made the difference?

    Would a skid fin help it steer better? Or does it need a real rudder? Or both?

    I worry about the motor hanging so far below the boat. Lotsa rocks and shallows around here. Could I tunnel this hull in order to raise the motor? There’s a couple inches between the hull and the seat that I could use.

    I’d appreciate any comments you have—I’m in awe of your knowledge.
     

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    Last edited: Sep 15, 2014
  2. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    Thje red colored boat looks every bit like a boat plan that was published in a how to build boats magazine of the late fifties. The plans were for a boat that some adventurous guy in the Florida keys built from two sheets of ply. He called it "The Thing". It went very well with a small outboard of less than 10HP. It was bouncy and probably great fun for the kids. (I still have the yellowed, ancient, magazine with those plans)

    I think that what I see in the pix has some disadvantages with an electric drive system. The boat is a planing type. Planing with electric power is not likely.

    The white boat in the last picture does not seem to be the same as the red colored one. That one might be better with electric power......Maybe.
     
  3. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    I think his name was Martin. The cockpit appears identical to the Tiki Kayaks. Try to track down a fellow named Danny Delo. Last I knew, Danny had a fiberglass shop and store in Fort Pierce Fl. Danny and Martin go way back.
     
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  4. tinhorn
    Joined: Jan 2008
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    Location: Massachusetts South Shore.

    tinhorn Senior Member

    Haha! I found The Thing on Google.

    I agree about the general hull shape despite my lack of design acumen. I'd hoped that at the slow speeds of a Minn Kota the planing hull wouldn't be a detriment, but that white dinghy was sure faster in the water. White dinghy's a blast but not as cool as the red boat.

    I'm thinking about experimenting with a stern tunnel to raise the motor a bit. Think it's worthwhile to round off the sharp edge at the bottom of the transom while I'm carving up the tail end? I don't think this thing will ever plane (with electric) but a little more speed would be nice.

    I bought a Tiki kayak this summer and the cockpits are identical. (Also the same as a Tempest kayak.) One of the forum members here said he used to lay up the Tiki kayaks. It's a Florida boat--seems those Florida boys share a lot of designs with one another. Must be really friendly folks.

    Will try to locate Danny Delo.

    Thanks, guys.
     

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  5. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    um, that would be me.
     
  6. tinhorn
    Joined: Jan 2008
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    Location: Massachusetts South Shore.

    tinhorn Senior Member

    And my Tiki kayak shows an excellent layup--no air bubbles at all under the gel coat! Well done, Phil!
     
  7. Stumble
    Joined: Oct 2008
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    Location: New Orleans

    Stumble Senior Member

    Tin,

    Adding a tunnel won't do anything but add more drag. The problem you are facing is that you are trying to use a boat designed for planing speeds at displacement speeds, and that will never work, or at least it wond work well.

    It looks like a cool little boat, but it is the opposite of a fast displacement hull and no amount of work will really change that. I you want to go fast with small amounts of power the only good option is long, lean, and light. What you have is short, and fat.
     
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  8. tinhorn
    Joined: Jan 2008
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    Location: Massachusetts South Shore.

    tinhorn Senior Member

    And I hadn't even told you about my motor-protecting skeg ideas! I guess it's easy to see why this boat never went into production. Haha--and why the molds were available!
     

  9. tom28571
    Joined: Dec 2001
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    Location: Oriental, NC

    tom28571 Senior Member

    Exactly.
     
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