boat designing help!! PLEASE!

Discussion in 'Boat Design' started by ber1023, May 29, 2008.

  1. Boston

    Boston Previous Member

    are foils allowed ?
     
  2. Seagull170
    Joined: Jan 2009
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    Seagull170 Junior Member

    Virtually anything is allowed, providing it's safe out in the North Atlantic
     
  3. Boston

    Boston Previous Member

    hmmm then maybe one of the more experienced members could show you guys how to take advantage of that in the design
    would be an eye opener to cut something off that old time of what was it,
    two hours fifteen ?




    now I realize its not a sailing race but the concept is the same

    a few even crude foils later and that displacement hull could be a flying hull

    take a look at Hydropter if you get a chance and notice the similarities with that tri huller you guys pictured a few posts back



    a three blade design like Hydropters could be simplified to lift something like Mr T's hull ( although you guys will want build your own design )
    and need room enough to move around and keep things ballanced
    you will have to look to some of the other members to help you with the specifics as Ive never built a foiler before, and you want this thing to kick *** first time in the water

    course
    they wrecked hydropter at 70+ mph
    and by some miracle everyone lived
    so if you go with foils
    and end up in the drink
    remember this warning

    dont try this at home

    we want pictures
    best
    B
     
  4. Mynhardt Coertz
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    Mynhardt Coertz Junior Member

    would a foil work with a motor , one would not want the prop clearing the water. Perhaps the foil could be adustable in its lenth pending sea conditions and the amount of clearance requiered yet maintaining enough depth on the prop ?
     
  5. Mynhardt Coertz
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    Mynhardt Coertz Junior Member

    With regard to stabillity I was wondering if two foils next to each other ofset at away angles would contibute, say two upfront and two at the rear
     
  6. Tcubed
    Joined: Sep 2008
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    Tcubed Boat Designer

    See , that' s the problem with posting unfinished drawings.

    The head of the engine is to poke out the deck. The cowl fairing allows it fresh air but some spray protection and cuts the windage and keeps the wash from spillin into the cockpit . The cowl is clipped into place or other easy method so paddling is no problem.

    The prop is hard to get to and is fixed in position so any probs would have to be dealt with with swim goggles and hanging inverted or some such . Not the most convenient, but everything is compromise.

    The strength issue is not a problem, you just build correctly. With all the weight concentrated amidships the only issue would be sagging loads which are much less than hogging loads can be.

    To get the whole thing flying on foils immediately means the engine must be adjustable height wise on the go, which is serious complication and inevitably more weight (which will have its induced drag price). Plus three times more complex stability and control issues. And you have to figure out how to get over the hump whilst reducing as much as possible resistance at the typical racing speeds. The advantage is the difference between drastically reducing wetted area resistance & wave resistance and creating a new resistance; induced resistance.

    It is certainly worth looking into but it is not an easy solution and would require quite a bit of experimentation before reaching close to optimization. With the foil stabilised VSV it is all very easy to predict, thus minimizing experimentation with real materials ($).
     
  7. Boston

    Boston Previous Member

    just throwing it out there Mr T
    hope you didnt think I was dissing on your design
    just having fun with what seems like a great project

    couple of questions for the more experienced
    could the rear wing be welded to the plate on the gear case housing to kinda automatically keep the prop in the water but flying and steering all at the same time
    and a couple of larger wings could go through hull at a little ahead of the center of gravity and angle down
    they could be belt sanded out of a chunk of aluminum
    maybe a couple of struts to hold it all together
    might fit that camper's budget just about right
    dont get me wrong
    Im all for optimization but that last 10% tends to cost 90% of the budget
    so the question is
    how perfect do these wings need to be and still work
    another question for the more experienced among the crowd is
    if the thing flies could it be shorter and still hit take off spead given s/l ratio's
    and if so how short given a 5 hp engine and x amount of wetted surface area including of course wings

    hell as long as we are welding stuff might as well cut up another gear case housing and weld an extension to the gear case and drive shaft to get the hull up off the waves better
    I seem to remember something about someones Dad being a mechanic
    guy might know how to weld

    those foils are ogivoil sections arent they
    kid with a belt sander and a few weeks could probably grind one out

    engine would need to move back from center some
    but there,s probably as many ways to do this as there are kids in Bermuda

    speed and safety dont get along all that well
    besides its not a party till someone gets hurt
    you guys must have a whole archive of great wrecks and things that sunk
    any film ?




    watch out for low bridges and
    you have my absolute best wishes in your quest for victory
     
  8. Seagull170
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    Seagull170 Junior Member

    Have a look on google earth.
    Bermuda 600 miles westish from North Carolina.
    The race is run anti clockwise & starts from just inside the point of the fish hook one year & almost the opporsite side of the inlet the next year alternating each year.
    Turn left at the point of the hook, shortest wat is a straight line those speckles in the water are coral, difficult to say how deep depends on the tide but look less than waist deep, normally good conditions here.
    Go between Island & shore art the first most westerly point, watch out for swimmers.
    Round the most westerly point deeper here, coral but not visible, ignore.
    Follow the cliffs close in as you sweep around to the most southerly point of the Island, swell now building up as you get closer to the coral ****** heads, the swell is confused with coral & cliff echoes appearing from all directions.
    Those white spots are niggerheads that appear 2 foot out of the water & then dissapear in a cloud of foam, calmest conditions just inside the coral line, but the straight line rule has you going through them all the time.
    Good surfing when you get it right but get it wrong & you'll understand the expression "submarine", but the water is warm.
    Slog all the way up the south shore , some of the best fun to be had without involving women, to the most easterly point doge the coral & turn left.
    Nice conditions here now 1 to 2 foot, not really a swell, turn left at Fort St Catherine, now your on the finishing straight, just pray there is no wind, if there is you'll be going almost straight into it, & it's a horrible short nasty only 2 foot chop, move the crew man as far forward as he can go to try & hold the bow down, when he comes out of there his colour won't be sun tan but bruises, just hope he's got a high pain threshold, or you've got to move the throttle like a throttle, not an on off switch.

    A beautiful ride with some of the nicest guy's who keep trying to pour beer down your neck. Mind you they do speak the strangest English!

    In the aftermath of a storm I belive they get a lot of floating Seaweed, don't foils stop working when they catch a bit of that, & how quick do they stop?

    Isn't the water on the north side of Bermuda the Sargasso Sea?

    Get that Seagull out of the shed & start thinking & working or start talking to the Bermudian racers if you don't weigh too much, you might get a ride as crew, you won't regret it!
     
  9. Boston

    Boston Previous Member

    good gods I think we have been invited

    ok important stuff there
    question
    is there any kind of penalty for hitting the swimmers
    or is it more of a point system

    rear sweeping foils might shed that weed automatically
    but that bit about dodging coral heads sounds a little
    well
    "dodgy"


    B
     
  10. Seagull170
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    Seagull170 Junior Member

    I can hardly invite you, I'm in England, I just go there to race.

    For hitting a swimmer you get a free 6 month holiday, & as an added attraction you get to be Bubba's ***** for your entire stay.

    You launch from a beach as well that might be difficult, but not as painfull as stalling with weed or sculpting coral.
     
  11. daiquiri
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    daiquiri Engineering and Design

    Hey guys, I feel like this idea about foils would spoil the meaning of this race. I mean though it is called a race, with its winners and non-winners, it still remains (as I've understood it from the videos in this thread) for the local population a moment of happy ride around the island with any hull available, even the most desperate one. Correct me if I'm wrong on this.
    If you start putting too much high-tech and muscles (with the relative costs), the others will have to follow and you will create something different, less joyful and easy-going ad more (or too) competitive.
    Imho.
     
  12. Seagull170
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    Seagull170 Junior Member

    Have no doubt it is a very competitive event.

    The locals I would guess would love to see a boat fly around the Island, the boats you've seen on this thread have evolved over the last 25 years, no doubt there are further advances to be made in hull design.

    If it looked like you were going to come to an untimely end, you would have to arrange your own safety boat, no ones been hurt yet, though many hulls have been broken.
     
  13. Boston

    Boston Previous Member

    so you say no rules and no ones been hurt yet
    ok
    launching ramp
    big one
    get some speed up and hit the water at lifting speeds
    ( sorry had a Wilie coyote moment there )

    I know this is a kids race :) so no worries
    I'm thinkin this can be accomplished Gilligan's Island style
    maybe have a short metal plate sticking out of the hull
    use some door hinges to attach the foils to swing up and down
    use a brace on another hinge to hold it down and support it when its flying
    with some kind of pin holding it to the foil that can be removed should you get fouled or need to clear the coral
    the top of braces should be up out of the water when the boat is at sub lifting speeds


    I'll make a sketch when I get a chance
    but I agree that the design should be made by the kids
    so I'll keep it just a sketch

    best everyone

    B
     
  14. Seagull170
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    Seagull170 Junior Member

    This is not a kids race, though there are some younger crews, the average age would probably be between 30 & 40.

    If you have a look a google earth, now work out how much of this island paradise is a beach that you would want the wind to push you onto.
    If the foils hinge back when they touch something you now have 2 underwater brakes that prevent you paddleing out of harms way.

    Sorry to appear negative, But if this is going to move forward in big steps let's make them well thought out ones.

    Surface piercing foils could be a very rational possibility if the answer to the to a floating plastic bag/floating weed stalling a foil or coral removing one completely question, or would seats & harness's be a necessity?
     

  15. Boston

    Boston Previous Member

    well if they could angle back enough then I think they would they would shed weeds
    any one got any experience with foils and weeds please speak up
    and if they were on hinges and struts they could be raised to avoid obstacles
    big question is
    how accurately do foils have to be and still function adequately
    Im just throwing it out there and seeing what comes back
    so no worries on the negativity
    might not work
    cant hurt to ask

    best B

    I still think the Acme beach ramp idea Would at least make for good showmanship



    what happened to ber1023
     
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