Did a dream got shattered?

Discussion in 'Boat Design' started by BertKu, May 16, 2010.

  1. tugboat

    tugboat Previous Member

    - NOW THAT WAS FUNNY!!!! ...good one!

    ..uhh..hmmm maybe both??

    Thanks for that info ill look into it...you know me--i love anything grassroots engineered...ill get back to you on it...cheers
     
  2. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Not a problem Dough, Between the three of us we are nearly part of the furniture at boatdesign.net. I had tremendous loss of time as my motors only were delivered after nearly 1 year, only this February. I utilized that time to make and design the controllers. I made controllers with only N types Mosfets and up to 4 x 100 Ampere types parallel x 6. The cooling is done via seawater and not a flimsy little blower. I also worked on the radio system whereby I only have two thick plus and minus wires. A kind of CAN system. I took an order for Europe for a wireless timing system and I will deliver that in May to Europe.
    Further, I stick to a solid old fashioned Hartley design, as I like working with wood and the wife wants reasonable comfortable sleeping area for 2 when sleeping over. Dough, for me, making the boat and system is 80% of the fun.
    It keeps me healthy and busy.
    Bert
     
  3. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    I still would like to get and appreciate an answer on "is there any good reason to buy Lloyd's approved Marine ply" instead of normal BS 1088 Marine ply? Gonzo, are you willing to give me a hand here?
    Bert
     
  4. tugboat

    tugboat Previous Member

    wish i could help Bert. i Think to cover your bases you might go with a loyyds approved then at least you are certain to get insurance but if it were me--id go with the cheaper of the two...bs 1088 isnt that loydds approved anyway??...marine ply is usually good quality--but check this vid out...
    comprison of marine ply vs ordinary play--you might be surprised at the outcome...

    http://www.youtube.com/watch?v=_ymE...DvjVQa1PpcFNORBmmlLNcD25LilMlr77T6UQj-DLdG88=

    Doug
     
  5. BertKu
    Joined: May 2009
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    BertKu Senior Member

    Thanks Doug,
    Interesting Video you posted.
    I got a private mail. He suggested that the glue layers must be black. I should cut a piece from each 3 type of wood I bought and soak it in sea water and thereafter boil it in seawater for a few hours. That would tell me what I should buy more off.
    Bert
     
  6. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    My guess is that you end up with ply soup if you do that.
     
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  7. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    I have always enjoyed soup !! By the way any comment on connecting a brushless motor, acting as a generator to a brushless motor with a screw (propellor)??
    No controllers, no electronics, just some wiring and wind. For smaller designed boats it should work.
    Bert
     
    Last edited: Apr 15, 2012
  8. tugboat

    tugboat Previous Member

    CDK knows his electrics!..i can vouch for that...you might try just soaking you ply for a month??..i dont know if boiling the ply would help or not--but try it at least and see...what can it hurt ? and if you get ply soup --then try a different method--if you really can afford the ply--go with Joubert! its like buying corecell in price but since its supposed to be the highest quality marine ply anywhere - you cant go wrong...

    the question is relevant as in those vids i sent: does the difference in price warrant as much difference in material strength??? is it only a small difference or is the difference in strength equal to the extra cost??
     
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  9. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi Doug,

    I am grounded for two weeks not to lift anything more than 1 or 2 Kg. I will certainly in 2 weeks time, boil all three products, before I purchase all the other 15 - 24 sheets. I cannot lift the sheets, they are between 9 and 13 Kg each.

    But to come back at the brushless motors and helix concept. Would it be crazy to have something like the attached photo instead of a sail/mast ? a brushless motor on the ax, 3 wires with some switches in between to the back of the boat. Have brushless motor build into the rudder with a screw (propellor) and go fishing.
    Bert
    p.s. the advantage is one does not have to tack.
     

    Attached Files:

    Last edited: Apr 15, 2012
  10. tugboat

    tugboat Previous Member

    I dont think its Crazy Bert- Its quite innovative, as long as you get enough power to operate your motors. or charge a battery bank...i dont know too much about electrics--i wish i knew more and will have to learn more later. but from what i recall you motor is very low power requirements --i think it could work-i also think there will be a lot of bugs to iron out as wlel..but im going with steam so --we all have a learning curve in these areas...

    do you have a drawing or pic of your reduced boat??
    p.s. i have a BAD back too--so im limited in what material to use..so steel is a no go. i understand that kind of pain. I did too much heavy lifting when younger and didnt lift properly or got overeager and had to prove i was stronger than everyone else and so i ruined my back...
     
  11. BertKu
    Joined: May 2009
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    BertKu Senior Member

    My experience is that if I have an innovative idea, somebody else in the world also has a similar idea. No, I was just playing with the 5 brushless motors I have and experimented with it. One does not need lots of rpm to get the other side turning. I am not planning to apply it in my design, I was just wondering. From reliable sources I was informed that a 1400kg displacement boat has sailed with 1 kw motor on reasonable rough sea. But I like to play it save and want at least 2 - 3 kw in total.
    I don't want another argument on the net, after I was let down by NZ, I decided on the way to Cape Town, that is it.
    I will give you a private mail.
    Sorry to hear that, that certainly will impair your dream of a tugboat from steel.

    When I came back from Cape Town on Tuesday, Wednesday I was on the operating table. Just a small problem. My back is fine since I am drinking 2 liters of low fat milk every day. Just hernia suddenly.

    20 years ago, the prof told me that he will see me on the operating table within a year for my back. That was 20 years ago. I discovered milk.
    Bert
     
  12. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Not without electronics Bert!
    Connected to a battery the motor will start spinning and use power instead of delivering. Only if the prop turns faster than the motor would do, it starts to supply electricity.

    In the early days of wind turbines people used a 3-phase electric motor and connected it to the grid. The idea was that if the wind lets the motor turn faster, it feeds current in the grid and the Kw counter turns backwards.
    That really works, except for the fact that if the wind speed drops, the motor starts drawing current again. So the owner had to sit in front of the Kw counter with one hand on the switch if he wanted to earn some money.
     
  13. BertKu
    Joined: May 2009
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    BertKu Senior Member

    No CDK, that is just the trick. You don't need any electronics. I have tested it with a 900 watt drill on the one motor acting as generator and tried to stop the other motor acting as the screw. It was impossible for me. It is the same principle that if a EV goes down the hill, that it charges the batteries. I also was very surprised that It just works on the back EMF. De nice part of it is , it start under load already at very low revolutions. Here is a short clip. Sorry CDK, I have tried to attach it twice now. Will have to make a plan to prove it to you. Now you understand how simple it is. One helix type of wind collector, a 3 phase brushless motor connected to the ax, a similar 3 phase motor mounted in a waterproof compartment and a screw (propellor). The rest is 3 cables with 2 switches to stop and reverse.
    Bert
     
    Last edited: Apr 15, 2012
  14. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    MP4 format not supported

    Hi CDK,

    My apology. I made a short clip with my mobile phone, however it is in MP4 format and that is not supported by boatdesign.net.
    I have sent you a private e-mail with this clip attached.
    Bert
     

  15. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Sorry Bert, I thought you wanted the generated energy stored somewhere.
    With another motor connected to the output you need nothing else, it is an application known as an "electric shaft". With your very efficient permanent magnet motors the losses are minimal, around 5-10% for the whole would be my guess.

    The EV going downhill or braking does need some control circuitry to charge the battery, but that's an entirely different matter.
     
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