20ft Nemesis Cat

Discussion in 'Boat Design' started by Alexander Peter Bromley, Feb 24, 2021.

  1. Alexander Peter Bromley
    Joined: Apr 2020
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    Location: South Africa

    Alexander Peter Bromley Student Naval Architect

    Some more progress updates. Mould is off the plug and busy with lay-up.
     

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  2. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    work, work, work !
     
  3. Alexander Peter Bromley
    Joined: Apr 2020
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    Location: South Africa

    Alexander Peter Bromley Student Naval Architect

    Haha!
     

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  4. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    Looking forward to seeing the finished product in action !
     
  5. Alexander Peter Bromley
    Joined: Apr 2020
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    Alexander Peter Bromley Student Naval Architect

    Gelcoat.
     

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  6. S V
    Joined: Jan 2019
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    Location: Lithuania

    S V Junior Member

    APB, are you preparing also the molds for the "top" of the boat? What is your idea for the other parts of the ship, not the hull?
    How they will be made?
     
  7. Alexander Peter Bromley
    Joined: Apr 2020
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    Alexander Peter Bromley Student Naval Architect

    Everything, plug to mould to product, except pipework this will be outsourced.
     
  8. S V
    Joined: Jan 2019
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    Location: Lithuania

    S V Junior Member

    APB, my English let me down this time... The question was more about the technology process you are planning to make the top parts. The same as a hull?
    Do you have the molds for deck already?
     
  9. Alexander Peter Bromley
    Joined: Apr 2020
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    Location: South Africa

    Alexander Peter Bromley Student Naval Architect

    It will be the same process as the hull, 3D model to cnc.

    We are busy with structure and deck this week.
     
  10. Alexander Peter Bromley
    Joined: Apr 2020
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    Alexander Peter Bromley Student Naval Architect

    Some progress on the Nemesis!
     

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  11. Alexander Peter Bromley
    Joined: Apr 2020
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    Location: South Africa

    Alexander Peter Bromley Student Naval Architect

    She's out the mould.
     

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  12. Alexander Peter Bromley
    Joined: Apr 2020
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    Location: South Africa

    Alexander Peter Bromley Student Naval Architect

    A few more pics of the hull, dusty and caught a few nicks on the way out the mould nothing too serious.
     

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  13. Bullshipper
    Joined: May 2008
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    Bullshipper Bullshipper


    32" wide is what the Seacat 22, Worldcat 23 and simular boats have here in USA and even with a flat bottom rear to provide more floatatiion, still ride nive and soft with 2800 lb dry hull weight. Other cats with keels like yours to track straighter hands free will usually have about 11 degrees deadrise even with light Al builds, which also looks less than your drawing at first glance. So it is my opinion that your width is fine as is, and depending on your weight, I would give here around 11 degree for AL and 5 degrees for a slightly heavier FRP build.

    I had a 26 Prokat planning cat that had 44" wide sponsons with around 10 degrees and their width gave he a rougher ride than the Seacat 22 I owned that was close to the same weight w/o engines. And off course the PK could take a lot more load which still did not help her much.
     
  14. Alexander Peter Bromley
    Joined: Apr 2020
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    Alexander Peter Bromley Student Naval Architect

    Thanks Bullshipper, that's good to hear, it's is quite scary going with an all new design but will see what happens on the water.

    Not to give too much away but my deadrise is a lot more than 15deg, so it will be interesting to see how soft the ride stays with the wider demi's and also from a straight tracking point of view.
     

  15. Alexander Peter Bromley
    Joined: Apr 2020
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    Location: South Africa

    Alexander Peter Bromley Student Naval Architect

    Some shiny new horses have arrived!
     

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