Efficient electric boat

Discussion in 'Boat Design' started by Jeremy Harris, Jun 22, 2009.

  1. joco
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    joco Junior Member

    you guys ever saw this or try it.?

    i like it a lot..at least the shape off it and how the lower unti as not mutch drag and all.


    i do like a lot.like a lot this little kit. how easy its to move it around its portability etc. and light..simply love it.

  2. joco
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    joco Junior Member

  3. joco
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    joco Junior Member

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    BATAAN Senior Member

    Wow, if VoltBoats can make that for $2700 they'll sell a lot I think. Perfect for covert military ops too. Autopilot, GPS, go-home feature, whoo, I want one. Now I can go to the Pub, get far too drunk, and the kayak will take me home. It used to be my horse but the rich guys on Wall Street stole all the money and I had to eat him.
  5. kerosene
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    kerosene Senior Member

    have to agree that the volt kayak is impressive that really is the price point.

    It will only work if they get big volume but the only way to get big volume is by competitive pricing. Needs serious capital to get all that working for that cheap.
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    BATAAN Senior Member

    I hope it works out for them. Totally agree about volume/capital problem that always plagues these startups. Unit in video looks like a beta test unit, kind of cobbled up but obviously nicely thought out and I'm loving the battery options. BUT you could mount an electric trolling motor through a vertical tube just big enough for the aluminum tube that connects the control head and submersible motor, connect a cheap small tiller autopilot hooked up to one of many available small gps units and you'd have something that could be retrofitted to any largish kayak. There are lots of these "sit-on" kayaks available, some are thermo-formed like this, others roto-molded out of PE. I once converted 3 fiberglass "18th century" longboats we used in the Bahamas filming a certain bunch of Pirate movies like this, using 36 volt motors assembled through a tube out the keel. They hauled butt upwind towing others, all loaded with extras in full costume, at night, in the rain. Here's a photo. Used 3 each 12v batteries wired in series hidden in a box under a thwart. The vertical tube of the motor was shortened quite a bit and a special low thwart built inside to take the top of the glassed-in steel (this is a movie job) tube that comes up a bit above the waterline.

    Attached Files:

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    BATAAN Senior Member

    Note behind: Yes, these were installed in the bows of these boats and worked fine.
  8. Jeremy Harris
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    Jeremy Harris Senior Member


    My electric boat development thread seems to have veered off into a speculative advert for what looks suspiciously like an investment scam to me.

    If this 'volt boat' is so great, why isn't there any real technical information on their website about it? All they seem to be saying is "give us a deposit NOW, or miss out on our wonder boat that is sure to sell quicker than we can make it".............

    There's no indication the boat exists, the pictures look photoshopped to me and the whole thing looks like an amalgamation of off-the-shelf bits tacked together (I'm guessing the hull is a bog-standard SOT canoe and the motor is a bog-standard trolling motor).

    This isn't 'efficient' within my definition at the start of this thread, in fact it's probably close to something anyone could bolt together for the price of a rotomoulded SOT, a cheap trolling motor and a leisure battery.

    A decent SOT is around $700 to $800 (see this one: http://www.madrivercanoe.com/produc...ation/adventure_destiny_series/adventure_16/), a cheap trolling motor is maybe $200 and a leisure battery should be less than $100, so what's so great about selling a package with all this in for more than double the price?

    Anyway, getting this thread back on track, an update. I've been testing the solar panels and they are better than I expected. I am pretty sure that I can get enough power from them in reasonable sunlight to sustain full cruise power, which is more than I'd hoped. Added to the approximately 8 hours of battery endurance, I am now confident that the boat can be completely self sustaining provided that I don't cruise for more than about 6 to 8 hours per day.

    The propulsion system is just about ready to go into the hull, with luck it should be fitted this weekend, when I'll add some photos to this thread to bring it up to date. I've made some changes, mainly to the way that the propulsion leg fits to the hull, as I decided against having it mounted in an outboard style well. It still uses the efficient prop inspired by Rick Willoughby's experimental work on his pedal powered boat though.

  9. portacruise
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    portacruise Senior Member

    Jeremy, I'm also generally suspicious of money forward schemes, so will watch to see how this one develops.

    Thanks for the update. I can't wait to see the final product of your expertise.

    Sorry if I missed this from a previous post, but is the boat meant to be self sustaining over more than one day, should it be travelling in unprotected waters? What is the expected full cruise speed?

    Applauding your accomplishment.

  10. joco
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    joco Junior Member


    first sorry about the tread.

    man reading all off it..i stop thinking it was a personal tread and more a electric yak tread at all...sorry again.

    the only thing i did is try to find good product to show you guy to guive ideals...

    for the volt yak...its no joke..its in few kayak fishing site already talking about them

    it sher look cool.


    will it be reliability .there is a lot off stuff in this yak...gears and motors and stuff that can go wrong..will see how this thing will turn out.

    2700$is not tobad for all this.

    i got 6 kayak here and i am doing 2 that will come electrics soon..so my kayaks run in the 1500$ plus a motor 200$(or bassyak kit that run into the 600$) plus time plus batterie plus wathever you will be over 2000$ in no time.anyway.

    its just one more option..like all other option..efficient i dont no i did said that because it could be nice..efficient mabe not in your standard.

    ((((((((((((((((((((i realy taught you would have like this thing.))))))))))))))))))))))))))))))

    and for the so great no one no if it so great plus....you will never see that many technical info in any site..this they try to keep for them.

    but if that thing ever come up you will see more info i am sher lika all other electric kayak on the market...i no a few and not many saw tecknical stuff.

    i personaly dont like the 100$ deposit thing taugh..weird...mabe a way to get some $$ i dont no..i dont think its a scam..but not sher how it will finish..but there is a market for those type off boats....and trully this is some ideals for all off you guys. that are into electric boat..mabe some even wont like it..because off some ideal out there ..anyway will see..if it ever goes out..
  11. joco
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    joco Junior Member


    Last edited: Aug 29, 2010
  12. bapou
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    bapou Junior Member

    first electric boat testing


    on the weekend, I performed the first water tests with my boat+electric setup. The purpose of the boat is very similar to the one Jeremy is building, a solar driven river cruising boat. My setup incooperates many ideas of Jeremy's
    great research.

    The testing was successfull, although the performance is still much behind of what was expected from the calculations. But there are many things which can and have to be improved.

    Short description of the present setup
    Boat: Classic 14, plan modifed from Geodesic Airolite boats (gaboats.com); this was described earlier in the thread.

    -chinese brushless motor HXT63-74
    -rewound to 12turns x 1.25mm^2 wire (by Ralph/powercroco)
    -added Hall Sensor, SS40A (information in endless sphere forum, as described by Jeremy)
    -homemade casing (mainly by Ignaz)
    -Sealing using a rotary shaft seal (nak tc 1230 7 5)

    different propellers were tried out:
    - Bolly 12x6 CFK
    - APC 12x8
    - CAM Carbon Power-Prop 12x8

    The spinner was lost in the testing...

    Motor controller (main information from the endless spheres forum)
    electric bike controller, infineon 6Mosfets, from ecrazymen/keywin (sold in ebay under the title 24V 250W brushless controller for E - bike & scooter )
    Modifications Motor controller:
    -changed Mosfets to IRFB 3206 (3Miliohm)
    -changed shunt
    -beefed up the board traces
    -removed the voltage regulator (to run with 12V) (as Jeremy described)
    -changed the resistor network for the voltage measurement of the processor

    Battery system
    4x HiTech 50Ah LiFePo, bought via the UK (David Cowperthwaite)
    Fechter/Goodrum BMS (information in endless sphere forum)
    some modifications were made to the BMS to minimze the heating and to allow mounting in the seasled PeliCase Box
    - MOSFET changed to IRF 1324 S-7
    - Resistors and LED were brought to an external circuit at the top panel of the battery case

    Results of the first testing (Handgeld GPS, and eagletree logger with Powerpanel, handwritten notes, therefore not very accurate):

    1.) Boat testing
    see the attached graph; The APC propeller worked less good than the other ones; maybe because of flexing. With two persons = roughly 350pounds of load, at 100W, the boat reached around 4.7km/h; increases of the power to 200W and 300W did not increase the speed very much (up to 7km/h).

    Some example RPM data (APC 12x8, 200pound load in the boat)
    100W 530RPM, 200W 630RPM; 300W 700RPM

    1.) Motor only testing; I run the motor at different loads, and calculated the characteristics using the Drive Calculator program. See the attached graph. The results are disappointing; ns = 107RPM/V, maximum eta is 70%. The main problem: Above 150W, the RPM and the eta are strongly decreasing. This explains why I did not reach the expected speeds...

    - The boat was faster when driving backwards! ( roughly +0.5km/h with the same power). Is this due to the bad hydrodynamics of the Motor/Propeller setup? Or do I have to mount the the (airplane) propellers backward. In the moment I mounted them in the same direction as in an airplane and thought that is does not matter. I will test this in the next days

    - The sealing of the motor axes does not seem to be 100% leakproof. Any ideas what could be improved? In the moment, it is an 12mm axes in a single rotary shaft seal.

    - The efficiency of the motor is poor; It is likely due to the large number of windings (to get the slow RPM), they increase the resistance ri. Jeremy, do you have (or can you produce) a similar diagram of your factory wound motors?

    I'm looking forward to your comments and ideas

    Thom (alias bapou)

    NOTE: The propeller was mounted backwards; mounting it right improved the speed; therefore the speed graph is meaningless
    The Bolly Carbon propeller was not 10,5x6,5 but 12x6; therefore the legend in the graph is wrong

    Attached Files:

    Last edited: Sep 7, 2010
  13. pistnbroke
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    pistnbroke I try

    Seems clear to me the motor is not low enough in the water and the flow is disrupted by the transom...if the photo is the running positon...
  14. bapou
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    bapou Junior Member

    on the photo, the motor is in its resting position. It is lower during driving...

  15. daiquiri
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    daiquiri Engineering and Design

    The keel and the motor casing in front of the prop are too thick and create turbulence, imho. Same for the transom. The upper half of the prop disc works in the transom wake.
    No wonder it works better when running backwards, imho, when the prop is fed by the clean waterflow.

    Ok, this was written before your last post...
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