making my own rudder (Hacker)

Discussion in 'Boat Design' started by Joris, Apr 21, 2014.

  1. Joris
    Joined: Mar 2013
    Posts: 59
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    Location: belgium

    Joris Junior Member

    Hey Folks,
    I started building a 20' runabout (Gladys from the Runabout book) last year and i'm getting in the fase where i need to fit rudder/driveshaft etc.
    In the runabout book it says ;
    "Rudder : To be of Hacker type. Made suitable to this job. Consisting of bronze rudder, special stuffing box, special hanger bracket, and sliding type tiller."

    Some info on what "Hacker type" really means or sizes would be very helpful. Also, if i find measurements i thought about making my own rudder in stainless steel, just not sure if it needs to be solid or not?

    All help is much appreciated!

    Joris
    Belgium
     
  2. Eric Sponberg
    Joined: Dec 2001
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    Location: On board Corroboree

    Eric Sponberg Senior Member

    Hi Joris,

    Hacker probably refers to the Hacker Craft boat company. Their website is:

    http://www.hackerboat.com/

    I am not sure that they indeed have their own style of rudder. However, other sources of powerboat rudder here in the US are:

    Buck Algonquin: http://catalog.buckalgonquin.com/category/rudders-2

    Western Branch metals: http://www.wbmetals.com/rudders.asp

    That should give you a start.

    Eric
     
  3. Joris
    Joined: Mar 2013
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    Location: belgium

    Joris Junior Member

    Thanks Eric,

    Now that i have an idea about sizes and shapes, i noticed most rudders have a solid shaft. Any reason not to use a hollow shaft (with larger diameter of course)

    Joris
     
  4. Eric Sponberg
    Joined: Dec 2001
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    Location: On board Corroboree

    Eric Sponberg Senior Member

    Joris, On small boats, one likes to use as small a rudder shaft as possible, particularly on rudders like these because the shaft is often thicker than the rudder blade. The swelling in the blade for the attachment of the shaft causes drag, which at high speed can be significant and can affect the way the rudder performs. Also, larger diameter shafts mean larger bearings and stuffing boxes which are more expensive and take up more room. Small solid shafts work best.

    On larger vessels, such as slow-moving sailboats, then hollow shafts can make sense.

    Eric
     
  5. Joris
    Joined: Mar 2013
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    Location: belgium

    Joris Junior Member

    Thanks again Eric!

    A found old chris craft rudder with 3/4" shaft. Beeing from the same period i trust it will do the job.
    I see most rudders have the shaft pressed into the blade and therefore need added thickness or swelling. If it was made from one sold if piece without the swelling, would that make a noticeable difference at moderate speeds?

    Joris
     

  6. Eric Sponberg
    Joined: Dec 2001
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    Location: On board Corroboree

    Eric Sponberg Senior Member

    The old Chris Craft rudder may work, provided the size of the boat on which it was originally used, the installed horsepower and the speed are similar to your boat.

    The reason stainless steel rudder stocks are mounted in cast bronze rudder blades is because stainless steel is harder and twice as stiff as bronze, although they are about the same strength. Bronze, on the other hand is easy to cast, easier to do than stainless steel. So the mix of the two materials utilizes the benefits of each.

    Therefore, it would likely not be that great a choice to have an all bronze rudder with the shaft cast in place with the stock. Conceivably, you could do it, however, and then machine the stock perfectly round after casting for proper turning in the bearings. Alternatively, you could use wrought products--a bronze shaft and bronze plate and solder them together. Finally, you could do the same with stainless steel--use 316L stainless steel for the best construction to minimize corrosion at the welds.

    Certainly, if you make the rudders without a bulge for an inserted stock, it should perform better than the traditional designs. You might not be able to judge or feel any performance effects until you reach high speeds, however.

    I hope that helps.

    Eric
     
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