Catamaran Hull Squat

Discussion in 'Hydrodynamics and Aerodynamics' started by francotripepi, Feb 28, 2019.

  1. Mr Efficiency
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    Mr Efficiency Senior Member

    He wants 8-10 inches, not much more than a heavy dew.
     
  2. Ad Hoc
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    Ad Hoc Naval Architect

    Well..with the fixed length of 7.30m...and an LD ratio of at least 7, that means the beam of each hull will be roughly 1.38m or 4 ft 6 inches
     
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  3. Mr Efficiency
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    Mr Efficiency Senior Member

    I say he might get away with a fat-hulled planing cat with jet drives and get a foot of draft. And have something that can traverse a little bit of chop without pulverising the occupants like a "flats" boat would.
     
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  4. fallguy
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    fallguy Senior Member

    I have been waiting for the opening.

    Bateau.com has a bunch of flats boats more practical for the sor.
     
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    It depends on what water he has to traverse, if there is choppy water over any distance, leave me out of a "flats" boat. I think a trailable cat, with dead flat demihulls aft, morphing into vee-hulls forward, in his stated size 24 x 8.5 feet, I'd go minimum 2'6 width to the demihulls, a tunnel around the same width, a little flam on the outsides gives you the 8'6, a draft of 12 inches at level trim would give a couple of tons of displacement, but you'd need jet drives. The boat would ideally be a lighter build, alloy or GRP sandwich. This would handle chop OK, if you kept the speed down to say 20 mph, which it should easily to be able to hold, with the flat and fat demihulls. I would expect a pretty lively, even unnerving action in a seaway, if wanting much more speed.
     
  6. francotripepi
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    francotripepi Junior Member


    Let’s see, bottom depth in never constant, so there will be places where you could go with a 2 ft draft, btw, 2 ft draft need 3 feet minimum to navigate at idle.....so you will be able to reach some places.....but having 8 to 10” draft allows you to navigate in 12 to 16” depts.....and that’s enough for most of these areas....that is why, most boats that venture in the Flats, mount their engines on Hydraulic Jack Plates, so they can raise vertically their engines in order to raise the prop closer to surface......this only helps at idle, where hulls do not create the void of water behind......if you see any show in TV or on YouTube on Flats Fishing you’d get the idea of shallowness......otherwise you’d hit bottom
     
  7. francotripepi
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    francotripepi Junior Member


    I would say around 12”.....anything else and you’re restricting where to go....
     
  8. Mr Efficiency
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    Mr Efficiency Senior Member

    What is the tidal range ? OK if the depth is the bottom of the tide, but who wants to get stuck, if it isn't !
     
  9. francotripepi
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    francotripepi Junior Member


    You are partially correct....chop around here is short and frequency is high....truly it’s the speed in which you move that might make it uncomfortable, but if you reduce speed, you reduce discomfort....and every boat is a compromise defined by the waters you spend most of the time navigating and the use you will need from your boat.....in the flats there are sandbars and tiny keys everywhere, hence speed is a relative need
     
  10. francotripepi
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    francotripepi Junior Member


    Got it....interesting
     
  11. francotripepi
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    francotripepi Junior Member


    Bingo....plenty boaters do get stuck....and the most common site in the bottom are lines that intersect.....they scar the seagrass and they are nothing else that the marks left by the skegs....
     
  12. Mr Efficiency
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    Mr Efficiency Senior Member

    I think the "fat and flat-tailed"planing cat with the central outboard, and jacking plate, could well be the go.
     
  13. francotripepi
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    francotripepi Junior Member

    C2F1F774-E013-491A-8B02-3229E8F123C3.jpeg E40F28FE-FBD0-403E-856E-40E6733F1258.jpeg 2A8997BF-C6AA-4965-9CE1-F0EC5E596E6E.jpeg 1BD826FE-DDE5-409B-9B08-8964C5911173.jpeg


    Welcome to the Flats.....this is where I love to boat and get “lost”......look at the pictures.....this goes on and on for miles....you have deeper channels between spots that run like highways, but most is like what you see....mangroves, Ibises, Tarpons, mantarays, all kind od fauna....absolutely stunning, none of those tiny keys (islands) are inhabited....only the main ones
     
  14. francotripepi
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    francotripepi Junior Member


    I believe you are also on the right track.....
     

  15. Mr Efficiency
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    Mr Efficiency Senior Member

    Any Permit ? There is a similar fish here called an oyster cracker, edible, but the Bonefish and Tarpon, basically inedible. I think I prefer catching good table fish.
     
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