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  1. #81
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    Quote Originally Posted by ksb51rl
    That's what I said! Except not necessarily better, just different.
    You guys are talking about aero/hydro-dynamic smoothness and the Roughness Reynolds Number

    I hate to disagree but the potential gain is so slight that it's marginal as to whether there's any benefit at all...maybe psychological but immeasurable in the physical sense

    Edit: I should include that the "roughness" benefit does exist at comparatively low speed but once the hull is planing that benefit is lost
    Last edited by PBO; 06-16-2010 at 06:51 AM.

  2. #82
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    The Triton just might get me back into FE. I first tried it 10-12 years ago. I spent well over $1000 to go 50MPH back then. After smoking a couple speed controls and an Aveox motor, I packed everything up and decided to wait until it became more cost effective.

    Looks like my wait is finally over. A 36" hull too. That'll help here in windy Oklahoma.

  3. #83
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    Quote Originally Posted by PBO
    You guys are talking about aero/hydro-dynamic smoothness and the Roughness Reynolds Number

    I hate to disagree but the potential gain is so slight that it's marginal as to whether there's any benefit at all...maybe psychological but immeasurable in the physical sense

    Edit: I should include that the "roughness" benefit does exist at comparatively low speed but once the hull is planing that benefit is lost
    So if we radar a boat back to back and consistantly record a high speed from boat to boat on different hull types how would you account for that?

    Also... I have seen the World Cup Sail boat teams on TV spend hours sanding the bottoms of their multi-million dollar sail boats. These guys have millions of dollars and highly trained aerodynamic and hydrodynamic minds working to optimize every inch of speed out of these boats. So if I see top teams for sailboats sanding the bottom of these boats I would think that there is some noticeable advantage.

  4. #84
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    Quote Originally Posted by PBO
    You guys are talking about aero/hydro-dynamic smoothness and the Roughness Reynolds Number

    I hate to disagree but the potential gain is so slight that it's marginal as to whether there's any benefit at all...maybe psychological but immeasurable in the physical sense
    Edit: I should include that the "roughness" benefit does exist at comparatively low speed but once the hull is planing that benefit is lost
    I'm willing to bet that if you take a boat that does say 50mph and test it with a gps before and then after sanding the bottom, you will acquire a slight gain in speed. It may not be noticable in the physical sense, but under gps i'm betting it will be.
    And personally i'm thinking the benefit will be gained at nearly any speed. Because either way the boat will be running on less of a wetted surface. I doubt the laws of physics change per low speed vs. running on plane. But I could be wrong.
    VXL Rustler on 3s
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  5. #85
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    Quote Originally Posted by nitrobaby
    So if we radar a boat back to back and consistantly record a high speed from boat to boat on different hull types how would you account for that?
    It maybe the psychological influence?

    Quote Originally Posted by nitrobaby
    Also... I have seen the World Cup Sail boat teams on TV spend hours sanding the bottoms of their multi-million dollar sail boats. These guys have millions of dollars and highly trained aerodynamic and hydrodynamic minds working to optimize every inch of speed out of these boats. So if I see top teams for sailboats sanding the bottom of these boats I would think that there is some noticeable advantage.
    I suspect you're referring to pre 2010 Americas Cup? & yes they do, they use a product on their hulls called Durepox & they sand to a 600g finish (generally) for a relatively low speed application. In this years event they raced multihulls & used different (some mechanical) devices for these types of gains

    One design classes & even offshore racing yachts (from supermaxi's to the smallest in fleet) do it depending on their knowledge & commitment BUT they do it for low hull speed gains. They're essentially forcing the boundary layer into turbulent flow, which offers benefit in light air conditions...

    Turn that scenario around & apply it to FE boats of hull speeds exceeding say 40knots. You'd be looking towards mechanical devices for hull speed advantages...like steps, airflow compression, ground effect, supercavitation etc

    Have a look at this project I'm involved in...it merges all these 'considerations' in a highly experimental platform that has shown some promise

    What I've explained here is far from a thorough explanation. The entire subject is incredibly complex & we can spend hundreds of posts discussing given examples but in the end it's very hard (almost impossible) to use much other than hardcore math to demonstrate the principles & the math leans toward my argument...I'm very happy to discuss though

  6. #86
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    Quote Originally Posted by PBO
    It maybe the psychological influence?



    I suspect you're referring to pre 2010 Americas Cup? & yes they do, they use a product on their hulls called Durepox & they sand to a 600g finish (generally) for a relatively low speed application. In this years event they raced multihulls & used different (some mechanical) devices for these types of gains

    One design classes & even offshore racing yachts (from supermaxi's to the smallest in fleet) do it depending on their knowledge & commitment BUT they do it for low hull speed gains. They're essentially forcing the boundary layer into turbulent flow, which offers benefit in light air conditions...

    Turn that scenario around & apply it to FE boats of hull speeds exceeding say 40knots. You'd be looking towards mechanical devices for hull speed advantages...like steps, airflow compression, ground effect, supercavitation etc

    Have a look at this project I'm involved in...it merges all these 'considerations' in a highly experimental platform that has shown some promise

    What I've explained here is far from a thorough explanation. The entire subject is incredibly complex & we can spend hundreds of posts discussing given examples but in the end it's very hard (almost impossible) to use much other than hardcore math to demonstrate the principles & the math leans toward my argument...I'm very happy to discuss though
    Yes. I would love to discuss further. I am just a dumb jock though. Ask me how to throw the boat in the corner an inch from the buoys completely blind due to six other boats thowing up a wall of white spray and still come out of the turn at the exit buoy still holding the same lane... I am your man but my comprehension of more complex dynamics is kind of slow... So I am excited to learn more in order to gain even more speed in what I am doing... to use the words of Denzel's Washington's Character in the movie Philadelphia... "Explain to me like I am a 6 year old" : )

  7. #87
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    never been into boats but looks as i will be pretty soon

  8. #88
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    Quote Originally Posted by nitrobaby
    Yes. I would love to discuss further
    Let me know how I may be able to assist, I'll do what I can to answer questions or theories

  9. #89
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    Quote Originally Posted by PBO
    Let me know how I may be able to assist, I'll do what I can to answer questions or theories
    What ideas would you have to optimize a vee bottom without adding steps? We cannot run steps in a vee hull in our organization. It will be considered a multi-planing hull or hydroplane so would have to run with the hydroplanes if we did that.

  10. #90
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    Quote Originally Posted by nitrobaby
    What ideas would you have to optimize a vee bottom without adding steps? We cannot run steps in a vee hull in our organization. It will be considered a multi-planing hull or hydroplane so would have to run with the hydroplanes if we did that.
    A couple of quick points;

    1. water is 1000 times more dense than air
    2. water buoyancy/density will vary depending on salinity, rain fall etc
    3. I'm not familiar with the racing rules generally

    OK, some ideas - in no particular order...

    - the hull should be as stiff as possible
    - a running plank will offer stability & reduce wetted surface area
    - shaft & water surface should be parallel to reduce vibration
    - exaggerate the width of the hull to form winglets to gain lift (like 1:1 25hp class)
    - reduce frontal drag to reduce the hull drag coefficient
    - install winglets to the base of the rudder to increase stability & provide lift
    - inject air/gas down the leading edge of the rudder to induce supercavitation
    - step trim tabs to reduce drag

    My ideas might be a little out there...I've got more but they're even wierder! I'm drawing inspiration from vessels like these




  11. #91
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    Now that's an interesting kayak, but it doesn't look too stable once you're stopped! (Not to change the subject... just found it interesting, being a paddler myself.)
    "Happiness depends upon ourselves." -Aristotle

  12. #92
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    Is it here yet ???

    Just kidding, Sure am excited about the boat and learning alot in the meantime. I'm going out today to pick up the material for the trailer frame.
    Sold a Shockwave 26 so it's $70 down $254 to go... (plus trailer)
    Never do anything half fast. Hey Ya'll, watch this

  13. #93
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    Quote Originally Posted by PBO
    A couple of quick points;

    1. water is 1000 times more dense than air
    2. water buoyancy/density will vary depending on salinity, rain fall etc
    3. I'm not familiar with the racing rules generally

    OK, some ideas - in no particular order...

    - the hull should be as stiff as possible
    - a running plank will offer stability & reduce wetted surface area
    - shaft & water surface should be parallel to reduce vibration
    - exaggerate the width of the hull to form winglets to gain lift (like 1:1 25hp class)
    - reduce frontal drag to reduce the hull drag coefficient
    - install winglets to the base of the rudder to increase stability & provide lift
    - inject air/gas down the leading edge of the rudder to induce supercavitation
    - step trim tabs to reduce drag

    My ideas might be a little out there...I've got more but they're even wierder! I'm drawing inspiration from vessels like these



    Hmmm....

    - the hull should be as stiff as possible (Check) Using Carbon Fiber

    - a running plank will offer stability & reduce wetted surface area (not legal in our organization. I like the idea though)

    - shaft & water surface should be parallel to reduce vibration (Check)

    - exaggerate the width of the hull to form winglets to gain lift (like 1:1 25hp class) I HAVE thought about this. What do you mean by the 1:1 25hp? Do you have a link?

    - reduce frontal drag to reduce the hull drag coefficient (Not sure I follow this)

    - install winglets to the base of the rudder to increase stability & provide lift (This is very interesting but may raise a red flag from the rule committee but I think it slips by... maybe I will have to check)

    - inject air/gas down the leading edge of the rudder to induce supercavitation
    (This is very interesting also. On our boats there are water injection holes in the rudder that shoot the water up through the moter to keep it cool. I was thinking to use a similar method along with the air pressure from the pipe that we also use to pressurise the fuel tank to provide the pressure to push air in front of the rudder as you suggest but I think the force of the water would over power the pressure of the exhaust pipe and fill my pipe up with water everytime I got up to speed. LOL! Otherwise I can't think of any other efficient way to do this... but I think it is a great idea.

    - step trim tabs to reduce drag

    This is a good idea. More and more boats are being designed so they need very little to no trim tabs at all though.

  14. #94
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    Quote Originally Posted by nitrobaby
    - exaggerate the width of the hull to form winglets to gain lift (like 1:1 25hp class) I HAVE thought about this. What do you mean by the 1:1 25hp? Do you have a link?
    I was thinking of what I know as wing boats. In Australia they run starting with 6hp for 8yr olds through to 25hp in long course events. The hull doesn't change, just the age of the driver & size of motor



    Quote Originally Posted by nitrobaby
    - reduce frontal drag to reduce the hull drag coefficient (Not sure I follow this)
    If you look at riggers, they've left traditional hull shapes in favour of purely functional, streamlined shapes. I'm wondering how much of the mono hull bow section really needs to retain it's traditional shape...if you could narrow that down to comprise only the essential elements you may be able to improve the aero drag coefficient?

    Quote Originally Posted by nitrobaby
    - install winglets to the base of the rudder to increase stability & provide lift (This is very interesting but may raise a red flag from the rule committee but I think it slips by... maybe I will have to check)
    I was thinking a simple end plate. I can't find a picture to illustrate but you wouldn't need much to give a profound effect without suffering drag

    Quote Originally Posted by nitrobaby
    - inject air/gas down the leading edge of the rudder to induce supercavitation
    (This is very interesting also. On our boats there are water injection holes in the rudder that shoot the water up through the moter to keep it cool. I was thinking to use a similar method along with the air pressure from the pipe that we also use to pressurise the fuel tank to provide the pressure to push air in front of the rudder as you suggest but I think the force of the water would over power the pressure of the exhaust pipe and fill my pipe up with water everytime I got up to speed. LOL! Otherwise I can't think of any other efficient way to do this... but I think it is a great idea.
    This won't be easy when applied to such a small scale but a soda bulb or similar would be sufficient charge if released in sufficient amounts to escape pinholes in the leading edge...

  15. #95
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    Quote Originally Posted by PBO
    I was thinking of what I know as wing boats. In Australia they run starting with 6hp for 8yr olds through to 25hp in long course events. The hull doesn't change, just the age of the driver & size of motor





    If you look at riggers, they've left traditional hull shapes in favour of purely functional, streamlined shapes. I'm wondering how much of the mono hull bow section really needs to retain it's traditional shape...if you could narrow that down to comprise only the essential elements you may be able to improve the aero drag coefficient?



    I was thinking a simple end plate. I can't find a picture to illustrate but you wouldn't need much to give a profound effect without suffering drag



    This won't be easy when applied to such a small scale but a soda bulb or similar would be sufficient charge if released in sufficient amounts to escape pinholes in the leading edge...
    Interesting! What is your background? How have you acquired your knowledge of all this?

  16. #96
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    Boats mainly. I run a large boat/ship repair business but have a variety of interests & experiences with a number of unusual projects

  17. #97
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    I cant wait,i cant wait!!!!! yeeeeehaa!!!

  18. #98
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    just pre ordered, have black jack 26 forsale!!!ha ha cant wait, save 30.00 on tower coupon

  19. #99
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    Quote Originally Posted by ebomb
    just pre ordered, have black jack 26 forsale!!!ha ha cant wait, save 30.00 on tower coupon
    People know of any more places to post boating equipment up for sale. I'd like to sell one of my custom jobs.

  20. #100
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    I'm seeing some input that only works on 1:1 scale boats and not FE
    some companies have tried to copy the hulls of full size scale boats and to find out some ideas just to not work and the FE boats run like crud
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