Is an inline rudder faster than an offset rudder?

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  • Steven Vaccaro
    Administrator
    • Apr 2007
    • 8718

    #31
    Originally posted by martin
    My friends Genesis was very squirrelly in the turns & would flip if to tight turn was taken, he had to take quite wide turns to prevent this. Switched to the offset rudder & it turns very sharpe much faster & stays flat & planted in turns now.
    Lets see a photo of how he made the conversion?
    Steven Vaccaro

    Where Racing on a Budget is a Reality!

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    • jevmax
      Legend
      • Aug 2007
      • 368

      #32
      Originally posted by detox
      A rudder that is not fighting itself to keep hull tracking strait is a fast rudder. For perfect rudder adjustment set rudder dead strait in line with centerline of hull (offset or inline rudder). Then remove turnfin and run the boat (accelerated quickly)then check to make sure boat is tracking strait. If not bend or shim your strut until hull tracks strait. Once strut is set do the same for turnfin making sure rudder is dead strait. You may have to bend or shim turnfin bracket to get hull to track strait.
      A major factor regarding your boat tracking straight or how much you have to ride the rudder to keep it going straight, is the prop. You can get the boat tracking straight, then change the prop and notice that it starts pulling to the right. Prop walk. Different props or a higher or lower strut height will cause more or less prop walk, and that can have a significant impact on your boats speed as you turn the rudder slightly to keep the boat tracking straight. With all of the interest in over powering and over propping FE boats to get the ultimate top speed, guys will see the effects of prop walk. When you are actually making a SAW pass, with timing lights and a 330' distance between them, one key to setting records is keeping your boat running straight through the time trap without riding the rudder. If your just running your boat for bragging rights using a GPS, it's not so critical. Just let the boat run in a big arc without holding the rudder, and you'll likely get its highest speed. A prop may make the boat go real fast, but it also creates so much prop walk that you can't run straight!

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      • jevmax
        Legend
        • Aug 2007
        • 368

        #33
        Now that we've breached the phenomenon of "prop walk", consider the role the rudder can play in compensating for it and thereby increasing your top speed. The amount of rudder area in the water is the only thing keeping the prop from walking the transom to the left and steering the boat to the right. Therefore a wide and/or deep rudder is a good thing, because if you have to hold any amount of left rudder to keep your SAW boat going straight through the timing lights you'll notice that kills the speed. It's another balancing act. The rudder is a major source of drag to a boat going fast. You want to have enough rudder in the water to counteract the prop walk, but not too much. Keep the rudder thin and wide, and just deep enough in the water to cause the boat going straight ahead.

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        • martin
          Fast Electric Addict!
          • Aug 2010
          • 2887

          #34
          I dont have a photo but i made one for another friend for his Miss Geico which was the same construcrion as the Kintec offset bracket. The one he made for the Genesis was pretty much the same idea. Martin.

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          • detox
            Fast Electric Addict!
            • Jun 2008
            • 2318

            #35
            Originally posted by jevmax
            Keep the rudder thin and wide, and just deep enough in the water to cause the boat going straight ahead.
            Good advice. Now I have to find one of those rudders. I may have to make my own.

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            • sundog
              Platinum Card Member
              • Feb 2009
              • 878

              #36
              Originally posted by JIM MARCUM
              PS: I was running a strudder on my 56" Segad. It was squirely as hell. www.youtube.com/watch?v=IPZGtssIXyQ Gonna put an offset on it & test it in a few weeks. Let you know how that goes.
              Jim, please do a test with a gps before and after if you are able (without changing anything but the rudder). There is little real info available on actual speed differences, mostly speculation. Thx, Sdg
              Legend 36 sailboat, KMB Powerjet Ed Hardy Viper, ABC jet pwrd BBY Oval Master, ABC Hobby Jetski, NQD Tear Into's, HK Discovery 500, MickieBeez pwrd Jet Rigger!, Davette/Gravtix jet sprint, KMB Powerjet Pursuit, NQD pwrd Jet Catamaran!,Steam pwrd African Queen, Sidewinder airboat, Graupner Eco Power

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