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 Post subject: Rudder arms
PostPosted: Sat Oct 09, 2010 6:13 pm 
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This is a bit silly. I started reassembling my rudders and noticed one of my rudder bars was 2" shorter than the other. I can't claim credit for that, but it has taken me a long time to notice.
Anyway, could someone please measure their bars (tube end to tube end) so I know which is correct?
Many thanks...


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 Post subject: Re: Rudder arms
PostPosted: Mon Oct 11, 2010 11:59 am 
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I'm not sure which would be correct, but it will be much easier making the long one shorter than visa versa. :wink:


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 Post subject: Re: Rudder arms
PostPosted: Mon Oct 11, 2010 3:22 pm 
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Yes that was an option, but the arm is pretty frozen at both ends. And I would prefer the longer arm if I can make it work.


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 Post subject: Re: Rudder arms
PostPosted: Mon Oct 11, 2010 3:39 pm 
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Ok... I'm confused.

Quote:
but the arm is pretty frozen at both ends


Tiller arm or tiller crossbar?

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Matt Miller
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 Post subject: Re: Rudder arms
PostPosted: Tue Oct 12, 2010 4:50 am 
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Sorry Matt, I'm on the other side of the world...

Out of each upper rudder casting emerges a pipe/tube, and these are connected by a cross bar. It is these pipe/tubes that are different. Straight ahead not much of an issue, but as soon as the tiller changes the blades are no longer parallel, hence my wish to correct the problem.

The easy way is to make them both short but the long one is frozen in tight at the rudder end, and the cross bar end is also locked in tight. I don't want to destroy it. Anyway I would prefer the longer option. My question to the Forum was which is the correct length - 450mm or 500mm?

Cheers, Hendo


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 Post subject: Re: Rudder arms
PostPosted: Tue Oct 12, 2010 8:59 am 
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Location: Oceanside, California
Fyi... as the rudders turn, they should not be parallel. This is due to a designed-in feature called "Ackerman". The inboard rudder turns sharper than the outboard one which allows a tighter turn with less rudder drag. This Ackerman effect is created by the tiller arms bend inboard towards each other... not tiller length differences.

Side note: Wave and Getaway using EZ Loc rudders do not have Ackerman due to a design issue with the plastic rudder housings which doesn't allow for bend in the tiller arms.

As far as the tiller arms being different lengths... I'd also suggest shortening the longer of the two. Seems the simple solution.

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Matt Miller
Director of Parts and Accessory Sales
Hobie Cat USA


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 Post subject: Re: Rudder arms
PostPosted: Tue Oct 12, 2010 11:12 am 
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Thanks Matt, Ackerman effect eigh, I wondered why the offset on the tiller arms, makes sense. Years ago I accidently reversed my rudders when setting up my boat. Fortunately it was pretty obvious when I connected the cross arm and was corrected before hitting the water. :)


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 Post subject: Re: Rudder arms
PostPosted: Tue Oct 12, 2010 7:31 pm 
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Thanks Matt, that is interesting. I understood that there was a difference between hulls in a turn but never heard of Ackerman....


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