V8 Hydroplane design.

Discussion in 'Boat Design' started by rebar, Feb 4, 2010.

  1. marshmat
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    marshmat Senior Member

    I'm afraid I don't have enough first-hand experience with such boats to offer sound advice on what plans to purchase. Looking at the Clark Craft there, it does appear that the sponsons are unusually shallow; a flat-water boat perhaps but best kept at the dock when things get choppy.

    You do want proven plans- not a prototype build. Making pretty drawings is easy; making drawings that are hydrodynamically, aerodynamically and structurally appropriate for this application is very difficult. A lot of hydroplanes have been destroyed due to one design flaw or another. These things are equal parts aircraft and boat- the airflow is a major contributor to lift and stability at speed- and are not easy to design.

    This is certainly a doable project for someone patient, mechanically competent, and reasonably good at carpentry. It does not need to be expensive; the materials cost for an 18' hull can easily be kept under $4k-$5k USD, much less if you're patient and resourceful. Your choice of powertrain and the level of finish desired (are you going with cheap gauges set in plywood, or Gaffrig Racing instruments in anodized aluminum bezels) will be the big budget-setters.
     
  2. dand0_4
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    dand0_4 Junior Member

    Boatdesigns.com has plans for small outboard powered hydros that I bet could be scaled up and modified for an inboard.
     
  3. rebar
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    rebar Junior Member

    That would be great. thanks
     
  4. mr hot rod
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    mr hot rod Junior Member

  5. powerabout
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    powerabout Senior Member

    a v8 in an 18 foot hydro would do well over 100mph you would want to be careful
    Hydro's are the fastest boats for any given engine class!

    you'll get some designers and builders from here;
    http://www.antiqueboatamerica.com/a...t=ForSale&Type=ListBoatType&Data=12&Name=Race

    build a classic with some stone age v8 and then slow will be cool and safe and both the engine and the boat will be a talking point.

    Just found this
    http://www.wildriversjet.com.au/hydroplane.htm
    I like the part where Jones supplied plans to ozzies for free? Must be a few around then
     
  6. rebar
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    rebar Junior Member

    I missed those. Thanks..

    I disagree.. I dont think a stock or mild V8 could push a 18' hydro over 100.

    Thats the plan.. Under power a hydro so its safe.. or safer..

    Another approach could be to design a hydro with less lift. Or no lift like Dan Ellisons top fuel "riggers". http://www.ellisonraceconcepts.com/ Which also makes the boat easier to transport since the sponsons are removable.

    How much speed would you sacrifice without any lift? Anyone..

    Yup. But not a stone age engine. A popular engine with lots of cheap obtainable parts. 350...:idea:

    Another thing Im unsure of is if a hydro be launched from a boat ramp? Looks like most of them have a high tiltable trailer (to make them narrow enough for transport) and require a crane to set them in the water.
     
  7. powerabout
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    powerabout Senior Member

    here's a stock ish class with our small ozzie v8 engine 253cu in (which also comes as a 5 and 6ltr version)
    http://www.ignitedesign.com.au/NSWHC/boatprofiles/classdefinitions.htm

    The 4.2 litre class is based on the 1970's Holden V8. Except for the camshaft which may be of any make or grind, only standard Holden replacement parts are permitted. The cylinders may be overbored a maximum of 0.040 inches. Compression may be raised by the removal of metal from the block or heads. (no domed top pistons) with a minimum combustion chamber volume of 53ccs. The standard intake manifold must be used with one four barrel carbie, either Rochester or Holley. Porting, polishing or larger valves are not allowed, nor is magneto ignition. Balancing, stronger springs and dry sumpimg are permitted. Fuel is restricted to pump petrol. Though 320 bhp has been registered on a dyno by a legal motor, 300 is generally quoted. Engines will run safely up to 7200rpm.

    The kilo record is 200 kph (124.4mph)
     
  8. TollyWally
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    TollyWally Senior Member

    Rebar,
    Go for it. Even the best of designs are tweaked for optimization after they are built. A friends brother had a shop building racing hydros. She gave me a tour one time, talk about cool, but that's another story.

    I was looking at a hull and saw these wierd appendages on the sponsons. They were basically new aluminum bottom sections grafted onto the plywood sponsons to give them more volume. They used aluminum so it would be strong enough being added on rather than being integral with the structure of the old sponson. I asked him what they were all about and he said it was an experiment. I asked him about the design and he grinned and said "we're sort of faking it, that's what we do , try something and time it." He then walked me around the shop and showed me several other hulls that had been grafted, cut away, etc. He said lots of ideas don't pan out, the best ones make the fastest boats.

    I guess my point is even the big boys sometimes resort to trial and error. I loved your fusion post.
     
  9. fishfighter
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    fishfighter New Member

    I been reading this thread with some interest because I was kicking the idea around myself of building one. Alot of the links ya'll posted gave some ideas and I want to thank ya'll for doing so.

    There are 2 boats left I what to build. One is a high speed hydroplane and the other is a power cat.
     
  10. Boston

    Boston Previous Member

  11. rebar
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    rebar Junior Member

    Yes. Iv found plans from Harlan Orrin. From the 60's but they are better then nothin.

    Where can I find prop shafts,stuffing boxes, struts, props etc?
     
  12. Boston

    Boston Previous Member

    get em used
    you will save a fortune

    best thing to do is buy a wreck from the boat yard and salvage what you can

    throw a party and have a bonfire with the rest
    assuming its a wood boat that is

    cheers
    B
     
  13. rebar
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    rebar Junior Member

    From the plans available from Harlan Orrin. I think the 1939 Plans for Ventnor 24 foot hydro " MY SIN/TEMPO VI might be the most suitable. Its a two seater and would fair better with boat wakes with its V bow.

    http://www.vintagehydroplanes.com/rctempo.html

    http://www.vintageboatinglife.com/Default.web/Ventnor 10 1938 24' Hydro.jpg

    http://www.vintageraceboatshop.com/It's a Wonder.htm

    Except its big at 24' and I dont know how well a chevy 350 would power it.

    The 225 Ventnor hydro might be a better option but need to find out the length.

    http://www.vintagehydroplanes.com/sunshinebaby1.jpg
     
  14. fishfighter
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    fishfighter New Member

    Myself,I am trying to stay under 18',better if under 16' and of course I am looking to power with a 350 ci.
     

  15. TollyWally
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    TollyWally Senior Member

    Where can I find...

    Years ago a friend of mine and I traveled several towns over and purchased the running gear from a small cabin cruiser a guy was selling. It was a great deal, $200.00 for a 327 chevy, BW gear, prop, shaft, rudder etc. He had sold everything else of value out of the boat and was hoping we'd haul the hull home and take it apart there. We asked him a few questions about what he was going to do with the hull and how careful we would have to be to just dismantle the parts and take them away. He said we didn't really have to be careful but wondered if we could accomplish it in a day.

    I broke out the chainsaw, made a few slices and within half an hour we were headed out of town with all of our booty still attached to a slice of the skin of the hull that we had manhandled into the back of my rather large delivery truck.

    Keep us updated on your project and post pics as they are available. Good luck.
     
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