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Catalina/Capri 25/250 Sailor's Forums

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IdaSailor High Performance Rudder

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Nautiduck
Master Marine Consultant

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USA
3704 Posts

Initially Posted - 12/17/2009 : 19:30:23

I am looking to replace my original Catalina unbalanced rudder. I looked at Catalina Direct and they sell the IdaSailor HDPE High Performance Rudder. I also am communicating directly with IdaSailor.

Has anyone installed this rudder on their C250? If so are you happy with the change? I am looking to improve handling and figuring a balanced rudder will make steering easier in strong winds. Yes, I know I should reef.

Also, has anyone upgraded to the Catalina balanced rudder. If so, how do you like it?

I generally go with the stock item (Catalina) but am liking the idea of HDPE and no chance of de-laminating, etc plus I think I've read positive things about the IdaSailor version.

We cannot direct the winds but we can adjust our sails.

Edited by - on

slaedlein
1st Mate

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USA
51 Posts

Response Posted - 12/17/2009 : 20:21:54

After breaking my beaching rudder

, I went with the Ida because of the positive feedback from others and the fact that they would provide a beacing ruder that would work with a wheel. (Catalina could not)Ida was vary easy to work with and seemed willing to make any sort of modification that might be needed. I am very satisfied and though not much of an expert, feel that it performs better than my original. It cost more than I was expecting, but I think overall, it was a fair price.

Edited by - on

Arlyn Stewart
Master Marine Consultant

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USA
2980 Posts

Response Posted - 12/17/2009 : 21:06:29

Hi Randy, the Catalina 3rd balanced rudder for the W/K version has had no handling problems but has suffered from some cracking between the pintle mounts. It has adequate depth and balance.

At one time, Catalina was offering it at cost, and at the time I bought my 3rd I think it was $300.

Most rudders if they have bottom paint on them should not be left exposed to the hot sun as it can expand them significantly and cause some integrity issues.

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JohnMD
Navigator

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USA
207 Posts

Response Posted - 12/17/2009 : 21:11:10

I've had an IDA kick up rudder with a tiller for a couple of years now. Love it. Soooo much better than the third generation Catalina rudder I had. Much less weather helm, less rounding up, and more control at slower speeds.

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bear
Admiral

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USA
909 Posts

Response Posted - 12/18/2009 : 17:20:34

I'll second what John wrote. I have had my IDA rudder for three sailing seasons now. No indication of roundups anymore, but this was an upgrade from 1st generation Catalina rudder. I am very careful in
reefing though. One difference I found was rudder must be off boat or raised when coming out of water onto trailer, it will drag. Never
had to raise it in the water because I don't beach anymore. I don't think you can go wrong though...JMTCW

Edited by - on

Seadog
Deckhand

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USA
13 Posts

Response Posted - 12/18/2009 : 17:31:35

I seem to remember a thread about Blair's Wind and Wood Boats of Clarkston Washington having a rudder similar to IDA. I don't know where IDA is made but I would like to plug spending your money with NW vendors - keep it local when you can!

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Arlyn Stewart
Master Marine Consultant

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USA
2980 Posts

Response Posted - 12/19/2009 : 07:10:32

John, do you have the water ballast? If so, your report is very much in line with what has been heard. However, we've not heard that the wing keel version 3rd rudder suffers the same lack of control. Remember, the 3rd water ballast and wing keel version rudders are different with the wing keel being much longer.

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Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 12/19/2009 : 09:13:38

Thanks for the feedback guys. Sounds like people like their Ida (made in Idaho) kick-up rudders and that is good to hear. I would prefer a blade (non kick-up) for my wing keel so it would be nice to hear if anyone has that version.

I think my current rudder, which is quite long, is a 2nd generation blade. Our 250 is a 2000 model. We have friends with a 2001 and it has a different blade rudder which I figure is the 3rd generation. Theirs has part of the rudder protrude forward under the transom. Am I correct that my rudder is 2nd generation? Is it reasonable to expect that the Ida or Catalina balanced rudders will make a noticeable difference?? Here is a photo of mine. Disregard the "A" and "B" markings which I made while contemplating the mechanics of a hard link.

Thanks for all the help!

Edited by - Nautiduck on 12/19/2009 09:16:28

Arlyn Stewart
Master Marine Consultant

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2980 Posts

Response Posted - 12/19/2009 : 13:25:11

Hi Randy... your picture is the 2nd, which was shipped with 2000 models, at least most of them. The 3rd was introduced as you suggest with the 2001 model.

As a side issue, during 2000 the wheel steering was discontinued for a while as Edson was redesigning the pull/pull cable system and Catalina the rudder with these being resolved for the 2001 model. So, your boat is very likely an early 2000 model, sometime between Dec of 1999 and May of 2000. I remember coming back from my 2000 summer cruise and talking with Gerry Douglas and the new rudder was in the mix then and the wheel steering option was discontinued.

Your 2nd generation has adequate control but suffers excessive torque because it is not balanced. The 3rd generation is about the same length as what you have but is of course balanced to reduce helm effort. Also, the rudder design is significantly different, whereas what you have would be called a high aspect ratio rudder compared to the 3rd, which is designed to produce more lift at slower speeds as well as of course being balanced to reduce helm effort.

Even though your 2nd has adequate control to avoid most roundups, it suffers having less control at slower speeds, whereas the 3rd has noticeably more control at slower speeds and especially in reverse. There is a trade off of a little more drag but probably not noticeable to anyone but a racer.

Edited by - Arlyn Stewart on 12/19/2009 13:32:45

Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 12/19/2009 : 14:46:20

Arlyn, thank for the information. A couple of questions:

What does "balanced" mean in a rudder?

The IdaSailor High-Performance is described as a "True NACA 0012 airfoil blade, balanced rudder for reduced helm effort. The high lift to low drag foil helps your boat to weather and increases speed off the wind." Is that what you mean by high aspect ratio? [url="http://www.idasailor.com/catalog/product_info.php?cPath=33&products_id=427"]IdaSailor High Performance C250 Rudder[/url]

Would you have an opinion on whether that rudder or the 3rd gen Catalina rudder would be better? We are primarily lake sailors in winds under 15MPH although the winds can kick in more that that on occasion.

Edited by - on

Nautiduck
Master Marine Consultant

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3704 Posts

Response Posted - 12/19/2009 : 17:57:40

OK, I did some online research and found that a balanced rudder fits this description (from Wikipedia):

Before the balanced rudder, all ships employed a rudder that was a simple flat piece of wood or metal, situated at the after end of the hull and hinged at the forward end, which could be angled to one side or the other to deflect the water passing it and hence provide an impulse to turn the ship. This required the exertion of significant force, as the passage of the water past the rudder tended to force it into a straight line in conformity with the flow.

The concept of a balanced rudder involved the shifting of the center of rotation of the rudder to a point approximately 1/3 of the way from the forward end to the after end. This meant that when the rudder was turned, the flow of water past the ship actively worked on the forward third to increase the angle of deflection, whereas the same flow acted on the after 2/3 to reduce the angle.

The mechanics of fluid dynamics produced a solution in which the turning force applied in one direction on the rudder by the passing fluid was balanced by the turning force applied in the other direction, allowing the rudder to be moved with only limited mechanical resistance.

It seems that there is a "sweet spot" for how far back the rotation point should be moved. The Wikipedia definition is oriented towards large power craft. For sailboats it seems like 15-20% is the range. Too far and the boat will turn too easily.

Now that I know what "balanced" means the concept does seem to make a lot of sense. Use some of the passing water to create a force that helps to make the turn.

Edited by - Nautiduck on 12/19/2009 18:48:19

Arlyn Stewart
Master Marine Consultant

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2980 Posts

Response Posted - 12/19/2009 : 19:18:55

Yep, the one third point isn't any good and is only a mental thing. Actually the point at which the balanced rudder balances is not a geometric balance but a balance of center of the hydrodynamic lift, which is a good bit forward of the geometric center.

Think of it this way, if the balance point were reached, then the lever forces would be equal fore and aft of the hinge line. The rudder would probably then go into flutter and not provide a course held smooth by the lever of positive aft pressure. The rudder would not be satisfied positionally and would flutter with whatever linkage play existed and the boat would have no hands off the rudder stability.

A slight bit more forward balance of neutral would see the tiller go hard over if one took his hand off it for a moment... so such a point is unworkable.

When I added balance to the 2nd generation beaching rudder by modifying the head to allow the rudder to position forward some, only about an inch or so was gained ahead of the pintle center line but it made a huge difference in the torque compared to the previous position of about two inches aft where the poor holding mechanism was positioning the rudder.

To your question of which rudder, Catalina 3rd or IDA... For the wing keel I'd say Catalina 3rd, for the water ballast beaching IDA.

Edited by - on

Nautiduck
Master Marine Consultant

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3704 Posts

Response Posted - 12/19/2009 : 19:20:36

(Simultaneous post Arlyn - I understand your point that it is not just the physical location % on the blade.)

OK now I'm getting into this balanced notion. Look at the photo of the IdaSailor balanced rudder for the C250:

Assuming that the pintles are the rotation point, there is actually not much of the blade ahead of the rotation point. Of course, on an unbalanced (standard) C250 rudder all of the blade is behind the point of rotation as the pintles actually extend out from the blade.

It is amazing to me that such a small difference in the amount of blade fore/aft of the rotation point can make a significant difference in handling.

Edited by - Nautiduck on 12/19/2009 19:24:40

Arlyn Stewart
Master Marine Consultant

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USA
2980 Posts

Response Posted - 12/19/2009 : 21:28:19

Randy, this is actually a very interesting concept to digest. My other interest besides sailboats is model airplanes. All planes depend upon balance as a flight stability issue. The closer that the plane can be balanced to the center of lift, the more efficient the lifting forces and less drag and more aerobatic it becomes but all that comes at a trade off to lesser amounts of stability provided by an aft positive lever trying to keep the wing angle of attack stable.

If the plane becomes too tail heavy, the pilot is then fighting to control a plane that wishes to either climb or dive but won't fly level. The same would be true for an overbalanced rudder, a straight course would not be possible.

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