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Old 11-03-2009, 07:31 PM
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Default Rudder Alignment....Toe In?

I have had the boat out of the water for the past week doing the annual maintenance and fall projects. Something I was thinking about is the rudder alignment. Have not measured or thought much about it since purchasing boat 2 yrs ago. Boat runs very nice so I guess that would be why I have not taken more time to learn about this topic. I would though like to double check things and improve wherever I can on how things are adjusted. I plan to do some engine alignment analysis once back in the water for a few weeks.

So what is the best way to measure the rudder alignment. Is Toe in the desired outcome and by how much? A 1/4 inch? From what I hae gathered so far they are parallel. Also the rudders are set just inside the prop nut, which I assume is standard.

Any info and advice is appreciated. We are putting the boat back in the water Wednesday night and all our other projects are complete so I would like to check this prior to launch and make any quick adjustments necessary.

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Old 11-03-2009, 08:10 PM
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I suggest you call Ocean and find out there opinion on the rudder alignment. Some boats rudders are aligned tow out and some tow in.
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Old 11-03-2009, 08:54 PM
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Quote:
Originally Posted by skiphughes View Post
I suggest you call Ocean and find out there opinion on the rudder alignment. Some boats rudders are aligned tow out and some tow in.
x2.

The deep V's, BF, Bert, etc., seem to spec trailing edges closer together than the leading edges, for more stern lift.

One of the guys on boatdiesel.com: loosen/unhook the 'slave' rudder, get up to your normal cruise speed, adjust the tie bar to the position the rudder falls in. Make sense? Sounds like it would certainly reduce drag doing it that way.

good luck!

Randy
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Old 11-03-2009, 11:24 PM
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Randy wisely avoided the terms toe-in or toe-out. If you do use either term it really helps others if you clarify whether you consider the forward or aft edge of the rudder the "toe". Most people feel their interpretation is obviously correct, but even different boat manufacturers do not agree which is which . That said, FWIW, I believe the manual for my Phoenix specs 5* toe out with aft edges apart.

I think a lot of manufacturers spec aft edge apart as a safety default as this tends to create a low pressure area under the stern and keep the bow naturally up which keeps it safest when needed most in large following seas. The drawback is that most of the time that configuration requires a good deal of tabs down to compensate.

Aft edges closer encourages higher pressure under the middle stern with bow lower effect , less tab down needed normally & less bow lift when running down into that next big sea. Deep-v hulls with substantial deadrise angle carried aft tend to stern squat so they may be more likely to try aft edges closer, though many still employ the safety default setting mentioned above.

Besides the increase or decrease in lift effect, the other good reason for not having rudders set just parallel is to avoid rudder vibration . Aft ends set either in or out will keep some side pressure on both rudders and prevent flutter. if just flutter prevention is the priority, the minimum "toe" +/- that prevents flutter would be best.

Letting the second rudder loose to set itself may work, but I would imagine chances of flutter could be great. That trick seems likely to work better with the directional powered drives of O/B's & I/O's . But if you let one free then added another couple few degrees tiller angle in or out as desired to that one it should work OK.

As Skip suggests, a call to Ocean Yachts should get both the mfgr's rudder spec and their rationale for it. Just make sure they define 'toe".
Ocean: eMail: info@oceanyachtsinc.com
Phone: 609-965-4616
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Old 11-04-2009, 01:10 AM
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yea ocean set the rudders just inside the prop nut for a very good reason and this is so that you could take out the propshaft to do repairs without removing the rudder, making life alot easier. my mechanic said that some of the older bertrams have the rudders aligned with the shaft, which well as you can see requires removing the rudder as well to take out the shaft.

just my 2 cents

Greg
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Old 11-04-2009, 09:14 AM
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Thanks guys. I know Tom at Ocean quite well. I normally have a few Q I like to ask prior to each project and he is very helpful. I spoke with him this am and on the 40 SS they like to have the aft edge of the rudder 3/4" out from the leading edge. I like to call that Toe In. So it looks like I will have some adjusting to do prior to launch. Thanks for the input above on the affects of each.

Should be a nice fall day in the Puget Sound for a afternoon run back to the home port.

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Old 11-04-2009, 09:53 AM
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I never really checked that closely, but I think mine are parallel. Trying to understand the concept; sounds like the "opposing" rudder angles keep the boat tracking straight while at speed. But isn't dockside maneuvering more complicated? IOW, if I set my rudder angle indicator to "0", but it's really slightly port or stbd- doesn't that complicate single-engine maneuvering?
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