Rudders and Rudder Stock Stainless 316 329 or Aquamet(aqualoy) 22

Discussion in 'Boat Design' started by fpjeepy05, May 24, 2012.

  1. TeddyDiver
    Joined: Dec 2007
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    Location: Finland/Norway

    TeddyDiver Gollywobbler

    Not so simple Frosty.. Like wave action affecting sway makes shear forces for the rudder shaft. Ad to that some torsion so you got some serious forces.
     
  2. Frosty

    Frosty Previous Member

    Looking at the internet ---sigh--- there appears to be a confusion over the word shear.

    Amercans call it bending,--- like in the cooking world broiling in uk is grilling. Gas to me is what I cook with.

    To me shear is guillotine as you would have on engine bolts taking engine thrust or the shear of the bolts on a bolted flange driving toque.

    It would appear that the USA meaning is more simple meaning a break.

    Serious forces from wave action and torque? --what on a 2 inch shaft.

    A 2 inch shaft would transmit 300 HP You going to generate excess of that with a hand held steering?

    Over engineering is bad engineering.
     

  3. MikeJohns
    Joined: Aug 2004
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    Location: Australia

    MikeJohns Senior Member


    Frosty, I’m sure you learned all this once in the dim past. Don’t get too confused by the internet either. The terms are the same worldwide and shear has been called shear in the UK since the inception of engineering. It might help to look up basic beam theory.

    Understanding shear is very important in engineering design.

    Perhaps read up on Bending moments and shear diagrams for a start.
    Direct shear is present whenever you load a structure with a force and there isn’t an equal and opposite force opposing. Then the supports push one way and the load pushed the other. There are two reactions one is the bending moment or your axial tension and compression. The other is trying to dislocate the structure laterally, shear strength of most materials is around 0.6 of its tensile strength.

    Also a shaft is subject to torsion it's not in tension and compression (Normal stress or bending moment) , it's being subject to shear.

    Your shaft and power transmission is another logical slip up, you are forgetting torque in that relationship. Torque times rpm should ring some old corroded bells somewhere in your past ;)
     
    Last edited: May 27, 2012
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