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Discussion in 'Boat Design' started by Guest625101138, Jul 14, 2008.

  1. Leo Lazauskas
    Joined: Jan 2002
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    No luck, again. The offset table in the Michlet file produced by Delftship has junk at the top, e.g. offsets of 1.039143E21.
    I have had this sort of problem many times with Delftship and Freeship.
    Shame, it is a great program for many things, but these sort of problems and its occasional inaccuracy are very disappointing.

    Leo.
     
  2. portacruise
    Joined: Jun 2009
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    Location: USA

    portacruise Senior Member


    Vic/Porta
     
  3. Guest625101138

    Guest625101138 Previous Member

    Leo
    I checked this one. Delftship had waterlines higher than the aft deck when I generated the last .mlt file. I deleted all the stations and waterlines from Delftship and just set them for the export to Michlet.

    Attached works in Michlet. Should have checked the first one. I cannot go deeper than 130mm because the aft deck does not have much freeboard.

    Rick
     

    Attached Files:

  4. Guest625101138

    Guest625101138 Previous Member

    Vic
    I never had to touch the prop this year. Just momentary stop and the leaves/weed just peels off. Even stuff that wrapped around the prop when I cut corners and went shallow into growing weed. A couple of back and forth motions with the pedals, blade flick in and out and the weed gets thrown off.

    The folding prop is a big step in overcoming weed. It gives me more design freedom with locating the prop.

    Rick
     
  5. kengrome
    Joined: Jul 2006
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    Location: Gulf Coast USA

    kengrome Senior Member

    I have considered the possibility of incorporating straws or coroplast into the hull so that the low pressure created via the venturi effect sucks air onto the hull surface as the hull moves through the water. Technically I think it might work without the necessity of a pressurized air system ... but if there were a surface treatment that would trap tiny bubbles of air at the hull surface it might be easier and more effective than drilling lots of holes in the hull and gluing straws into them.
     
  6. portacruise
    Joined: Jun 2009
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    Location: USA

    portacruise Senior Member

    Bubbles do work and this is a clever approach. Sometimes there is marine life we can mimic to increase efficiency. Like the olympic swimsuits that have ridges which mimic sharkskin?

    Porta

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

    kengrome Senior Member

    In light of this report that Rick posted in another thread (it's a PDF file, see figure 15) it seems that my straw concept might work best in the aft portion of the hull bottom since that's where the low pressure on the hull will create suction:

    http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=8895319&article=0〈=en

     
  8. I57
    Joined: Feb 2008
    Posts: 172
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    Location: Melbourne, Australia

    I57 Senior Member

    Seats

    Just changing the subject for a moment, have made a new seat and am using an inflatable cushion for lower back support. Tried it for the first time today and went for 1.5 hours with no aches. The cushion gave good support but also allowed movement when pedalling, the problem with the old one was sitting in one rigid position all the time. Does anyone else have seat problems?

    Ian
     

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  9. Clemens
    Joined: Jan 2010
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    Location: France

    Clemens Junior Member

    Hello TT,
    found your description and photos by chance. Seems we share a lot of ideas and preferences!
    I did some work on my seacycle twin in order to make it fit for multi day excursions.
    Best greetings
    Clemens
     
  10. Clemens
    Joined: Jan 2010
    Posts: 14
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    Location: France

    Clemens Junior Member

    Cruising Seacycle

    Hello,
    I'm new to this forum, signed in today, after Rick sent me the link to this very interesting thread.
    Thrilled about your modified Dart catamaran!

    Three years ago, I modified my seacycle twin in order to transform it into cruising vehicle. After a 2 day trip to the canal connecting the rivers Rhine and Marne I added another platform section to put up a small tent on the deck. I made several 3 day excursions on Lake Konstanz, Germany.
    Next I'd like to make a lighter and wider platform of foam, epoxy and fibre glass / carbon fibre.

    Enclosed you'll find a report in Velo Vision.
    Cheers Clemens






     

    Attached Files:

  11. Guest625101138

    Guest625101138 Previous Member

    Clem
    Have you made any plans for the deck modification?

    Are you only in the thinking stage or have you got a finish date in mind?

    Rick W
     
  12. Clemens
    Joined: Jan 2010
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    Location: France

    Clemens Junior Member

    New platform / deck for Seacycle

    Rick,
    so far, I only did some sketches.
    It would be great to test the new configuration in June.
    Will send layout soon.

    My goals:
    • bigger platform / deck - 230x140 instead of 190x90
    • lighter (20 kg less)
    • lower profile (-8 cm)
    • less parts to assemble
    • faster to put together
    • more appeal to my son to come along on a boat trip :)

    Best greetings
    Clemens
     
  13. Guest625101138

    Guest625101138 Previous Member

    Clem
    There is some free 3D CAD software called Delftship that can be used for drawing up things like you propose so you can visualise them. It also allows you to get accurate measurements of pieces.

    Takes a little bit of learning but is worth the effort if you do not have access to other CAD software.

    It can be a challenge to get children to join you in the things you like doing. As they get older they have their own interests. I think you would have a special child who enjoyed pedalling on the water.

    Rick
     
  14. blisspacket
    Joined: Jun 2005
    Posts: 55
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    Location: st augustine

    blisspacket Junior Member

    Great report, great effort. Thanks for sharing, Rick.
    Is there any merit to a pulling folding prop that might not require a strut?
     

  15. Guest625101138

    Guest625101138 Previous Member

    Believe it or not (I can show video) a pushing prop is self stabilising. As long as the prop pushes and is on a curved shaft it will align itself with the flow. A pulling prop would want to dive.

    Rick
     
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