Designing a 20 ft power cat

Discussion in 'Boat Design' started by B. Gabor, Sep 17, 2012.

  1. B. Gabor
    Joined: Sep 2012
    Posts: 2
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    Location: Hungary

    B. Gabor New Member

    Hi,
    I'm new here but I read this forum a long time, and I think there are many people who are adept at designing power catamaran hulls... Last year I decided to make a relatively small cat (approximately 20ft.) a bit similar to large offshore catamarans. The design of deck is almost complete, but my problem is that I don't know how it will work with this size. I don't want to build a cruiser, but a faster open boat without a cabin (with 80-100 hp outboard motor). I will upload a few images of my idea and I hope that you can advise in this context.
    Here is a screenshot of shape of the hull.
    Thanks in advance!
    Regards, Gabor
     

    Attached Files:

  2. tunnels

    tunnels Previous Member

    Its a tunnel not a cat !!!! understand what you doing !!!!

    Its not a Cat!!, its a tunnel ??
    what you have is a tunnel hull differant from a cat !!!
    The dead rise is way to shallow and will be a thumper and hard riding the tunnel width is way to wide as well and will hit every wave really hard believe me i build lits a tunnel boats and dont like cats at all !!!!!tunnel roof in a tunnel boat is the key to its success get that wrong and it will not perform very well at all !!!,
    tunnels hulls are born from race boats so horse power on a 20 foot tunnel 2 x150s or a single 250 hp would be ideal !! 80 OR 100 HP forget it you are wating your time it wont go very good at all !!!
    What you have is a performance hull and should be treated as such underpower and you have a dog .
    Cats are cats and tunnels are tunnels !! they do not perform the same and the technology for each is completely differant from each other !!!!!! Back to the drawing board !!!:eek:
     
  3. Frosty

    Frosty Previous Member

    Lots of money and work for something that might not work.

    There are hundreds of these boast on the market that will cost half of a risky build --

    You and the dog could be fishing this time next week.
     
  4. tunnels

    tunnels Previous Member

    You are right theres got to be a herd of boats out there for sale about that size.
    And yes you and dog could be fishing next week ! :D
     
  5. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    Isn't Hungary landlocked ? Where are the waves that will make it a 'thumper' ? On the Danube ?
     
  6. tunnels

    tunnels Previous Member

    Ok it will be a noisy boat and with a tunnel that wide the air going under will never compress and help lift the boat !! thats what the tunnel is for !!! its not just there to look sexy and make the boat stable at rest it has a very important role to play !!!Like i said its based on a performance boat design so take advantage and get the best .
    Yes rivers and lakes can get a little lumpy at times with wind and wakes from other boats and thats where tunnels really come into there own in those conditions Check out this site if you want to learn something !!www.aeromarineresearch.com/
     
  7. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    How do you figure a narrower tunnel will supply more lift ? Makes no sense to me.
     
  8. tunnels

    tunnels Previous Member

    Just have a look at a few tunnel boats the penny just might drop that its out of proportion !!!:eek:
     
  9. B. Gabor
    Joined: Sep 2012
    Posts: 2
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    Location: Hungary

    B. Gabor New Member

  10. tunnels

    tunnels Previous Member

    That cat come tunnel has a hydrofoil across the tunnel and thats a whole differant thing . It take extra power to push and raise with a hydrofoil where as a true tunnel rides on a cushion of air between the hulls . sounds simple but its tricky !! get it right its magic get it wrong its unmagic . :D
     
  11. Frosty

    Frosty Previous Member

    Hes not asked for performance or lift -- --he said he wants to go fishing.

    Why don't you ask for more information.

    Maybe he wants a cat for stability.
     

  12. Mr Efficiency
    Joined: Oct 2010
    Posts: 9,899
    Likes: 880, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    He did ? :confused:
     
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