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how to align the new rudders
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Author:  greensnopro [ Tue Jun 21, 2016 1:55 pm ]
Post subject:  how to align the new rudders
I finally got some new to me Epo's on the old cat, now I have to fix the hum, it's actually worse than the stock ones were.
So last weekend I installed new cam locks and adjustable upper castings and the rudders, then I came to alignment and realized I had no idea what to do as far as where to point them from what position. I found the screw under the tiller cross bar to adjust with, but do you adjust them with them up and point them to the Bow tip? or someplace? or with them down and square them off the transom? or what?
I sailed the boat and it seemed ok with minimal pull, but maybe more turbulence around the rudders, and a lot of hum.

Image
Author:  rattle 'n hum [ Thu Jun 23, 2016 1:00 pm ]
Post subject:  Re: how to align the new rudders
Check the rudder alignment section of this article on the support page:

http://www.hobiecat.com/articles/rudder-tuning,87/
Author:  greensnopro [ Thu Jun 23, 2016 1:32 pm ]
Post subject:  Re: how to align the new rudders
Thanks Jerome, I did find a video on youtube that covered all that but they both still lack on the exact point of rudder "aim" I will call it. I'm kinda leaning with using a square to the transom and then set the toe in.
Author:  rattle 'n hum [ Fri Jun 24, 2016 12:40 pm ]
Post subject:  Re: how to align the new rudders
If I understand what you're saying, I think it will be difficult to square them from the transom because you'd need to keep them dead center during the operation and since they're foil shaped instead of flat. We just lock them down (lower the front of the trailer if necessary) and measure the leading and trailing edges at the widest part with a steel tape measure. (You really need two people.)

Good luck!
Author:  greensnopro [ Fri Jun 24, 2016 3:18 pm ]
Post subject:  Re: how to align the new rudders
okay so I guess rather than trying to set each one to a dead straight ahead (and then add the toe in) I'll just make them with the toe in and see what happens.
What I'm concerned about is having one straight and one a few degrees off of straight forward which would create more drag.
I guess if they are the same distance apart maybe it would be just be an off center thing to go straight.?
Maybe I'm over thinking it, in my mind i wanted to center the tiller extension with the center of the aft cross bar and then adjust the rudders to perfect straight and then take and 1/8 in on each side, I just don't know how to find the perfect dead ahead spot to align with.
Author:  rattle 'n hum [ Sat Jun 25, 2016 8:31 am ]
Post subject:  Re: how to align the new rudders
Okay....I see what you're saying now. If you have adjusters on both ends, the optimum would be to adjust them equally so that the yoke for the hiking stick is centered AND the desired toe-in is achieved. However, if you only have the adjuster on one end (or if one is stuck), there won't be extra drag on the rudders as long as the toe in is right. The yoke just might off center by an inch or so, which is no big deal. Case in point....on boats with the newer (H20 style) connectors, the adjuster is only on one end of the crossbar.

As with most connectors on older boats, be careful not to damage/shear the adjusters/set screws during disassembly...they're notorious for getting stuck with galvanic corrosion. Patience and PB Blaster helps. During reassembly, I'd recommend a little tef-gel or lanocote. I use lanocote on pretty much everything on the boat......even on metal house plumbing!

Hope this helps!!

Edit: This may be more to your point about "squaring" the rudders for the toe-in adjustment........So long as the rudders are CLOSE to centered, the difference in rudder angles (relative to one another) due to the Ackerman steering principle is negligible. That difference increases the further the rudders are turned away from center.
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