20ft Nemesis Cat

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

  1. Jimboat
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    Jimboat Senior Member

    Alexander - yes, that's me. Good luck with your project. Looks like fun.
     
  2. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    Great! I will order a copy this week.
     
  3. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    It's been a while, had a bit of a dud builder who needed too much micro-managing for my liking so onwards to another company who is enthusiastic about building boats!

    In the meantime I the company I work for managed to run a CFD analysis on the Nemesis. It looks promising. No signs of porpoising or dynamic instabilities at our desired operating speeds.
     

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  4. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    In the below image the software can indicate how much lift the demihulls are producing for a given speed. The grey line being the hull draft at rest compared to the speed in the colored in hull.

    upload_2021-8-10_22-38-47.png
     

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  5. Mr Efficiency
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    Mr Efficiency Senior Member

    Is the original design unchanged ? It just seems the deadrise angle is less, but of course that is purely a notion that came into my head ! Did you ever consider a plank bottom to the hulls, it would have dug into the sand less.
     
  6. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    Hi Mr E. Yes the design is unchanged I did think about it but I would rather sacrifice the digging into the sand on the beaching then overall ride. Some of the SA boats have flats towards the transom which helps with the motors being able to be mounted higher as the transom height is reduced.
     
  7. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    Some more progress.
     

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    BlueBell and cracked_ribs like this.
  8. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    Progress report.
     

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  9. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    She's coming along nicely. Finishing up the plug and then onto the mould.
     

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    BlueBell likes this.
  10. Mr Efficiency
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    Mr Efficiency Senior Member

    Looking good, big job.
     
  11. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    Thanks Mr E. the "fat cat" is coming along haha!
     
  12. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    Some more progress, onto the mould-making.
     

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  13. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    Afew minor updates made to the stainless and T-top
     

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  14. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    .
     

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  15. Alexander Peter Bromley
    Joined: Apr 2020
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    Alexander Peter Bromley Student Naval Architect



    Nice example of South African skiboating.
     
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