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JohnMD
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USA
207 Posts

Initially Posted - 07/06/2006 : 13:34:34

Hey, all you guys with IDA rudders. Should I spring the big bucks for an IDA or not??? Will I be saying 'WOW' when I sail with it or will my wife be saying 'I told you so'??? I have a third generation rudder on a 250 WB and it is woefully inadequate. thanks a bunch

Edited by - on

RSHOOTER
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USA
101 Posts

Response Posted - 07/06/2006 : 14:37:50

Well, John I think you would be pleased. I have a kick-up IDA on my Wing Keel as it aids in storage being able to break it down. Much less weather helm with it. If you buy one I would recommend buying the Tiller as well otherwise you have to make some modifications. Joel will also drill and mount your Gudgeons if you give him the measurements. When you bottom paint it you have to lightly sand it to get the paint to stick.

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raulpou
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144 Posts

Response Posted - 07/06/2006 : 21:19:56

I wonder if it works with the wheel steering?

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JohnMD
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207 Posts

Response Posted - 07/07/2006 : 07:09:37

How much deeper does the IDA hang in the water? Looks to be a foot and a half or so. I've done three windy regattas with my boat. Besides being worn out trying to hold the tiller all day, once I had the boat round up and actually tack. Besides that, dragging the rudder thru the water sideways all day doesn't do much for performance. Thank you for your opinion. Anyone else with an IDA rudder have an opinion. (I understand opinions are hard to find, ha, ha,)

Edited by - on

Arlyn Stewart
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2980 Posts

Response Posted - 07/07/2006 : 10:47:18

<blockquote id="quote">quote:<hr height="1" noshade id="quote"> Besides being worn out trying to hold the tiller all day <hr height="1" noshade id="quote"></blockquote id="quote">
This comment surprises me a little as I thought the balanced 3rd short had reduced the effort to a reasonable degree. This leaves me wondering if there are other trim issues needed dealt with.
</ul> <ul><li>Is the boat balanced on her lines?</li><li>Is the mast rake a little forward of specs?</li><li>Is the center board positioned with some aft rake?</li><li>Is the rigging tension firm?</li><li>Is the main sail old and blown out?</li><li>Is heeling limited to twenty degrees?</li></ul>
Each of these will make individual contributions to increased weather helm and increase the rudder control needed. I'm not defending the 3rd generation rudder(short) as I've been on the record as saying it is inadequate (lift wise) for aggresive sailing conditions but the deal seems to me that on a tiller boat, the effort isn't going to get any less than the 3rd short offers as it is a very well balanced rudder, which I felt was as close to the zoom zone as design allows.

Zoom zone? Zooming occurs when a control surface is over balanced and constant effort is needed to keep it centered (very undesirable).

In fairness to Gerry Douglas's design of the 3rd rudder, looking first at the problems of the 2nd generation rudder.
<ul><li>Too much helm torque</li><li>Slow speed performance of rudder was inadequate for docking</li><li>Rudder was longer than the keel and was being damaged</li><li>The beaching rudder was overstressing steering systems</li><li>The blade on the water ballast had to be removed for launch and retrieve and if forgetting was getting damaged</li></ul>
His design of the 3rd....
<ul><li>Reduced helm torque by balancing</li><li>Increased slow speed docking performance</li><li>Limited the rudder for the water ballast to a rudder shallow enough for launch and retrieve</li><li>Limited the rudder depth on the wing keel to the depth of the keel</li><li>Got rid of the beaching rudder</li></ul>
Were there compromises in the design or was all for the better?
<ul><li>The water ballast didn't get a rudder adequate for aggressive conditions</li><li>The water ballast lost the beaching rudder that fit its needs much better</li>
So, the outright winner was the wing keel while the water ballast mostly lost leaving many water ballast owners unhappy with the 3rd generation rudder. When looking at the goals, the only plus for the water ballast boat with a beaching rudder was less torque as most were linking the rudder and outboard anyway for docking. Solving the torque was simple to achieve with the 2nd by adjusting it's rake and changing up the poor hold down system. Unfortunate, was that the goal to get rid of the beaching rudder was in my opinion a misguided goal, and should have more reasonably been to correct the hold down system that was causing the problems with the beaching rudder.

The real winners were the owners of other brands of boats that were buying (even coming to this forum to solicit) the Catalina 2nd beaching rudders from those who upgrading to the 3rd.

Sorry about the digression...

Edited by - Arlyn Stewart on 07/07/2006 10:52:59

AADIVER
Admiral

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USA
966 Posts

Response Posted - 07/07/2006 : 10:57:15

When I bought my 2001 WK last December the original owner had "misplaced" its rudder, so he replaced it with whatever the current factory model is. I find it performs very well, especially when the main sheet traveler is always leeward which counteracts weather helm.
PRETTY PENNY requires degrees of reefing, either jib (110) or main, in winds over 15 knots to maintain under 15 degrees of heel on close reaches.
BTW, how do IDA rudders differ from those made by Catalina, and why are they so bloody expensive?

Edited by - on

JohnMD
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USA
207 Posts

Response Posted - 07/07/2006 : 11:50:33

* Is the boat balanced on her lines? NO, the bow is a couple of inches higher than stern

* Is the mast rake a little forward of specs? No, I was silly enough to set the boat up the way the manufacturer specified. However, I had to move the rake forward to do this and didn't notice any difference.

* Is the center board positioned with some aft rake? Yes, however I spent all day moving the centerboard up and down and it made little or no difference.

* Is the rigging tension firm? Yes, no slack in my leeward wires.

* Is the main sail old and blown out? Yes, my wife said something about freezing over before I can get another.

* Is heeling limited to twenty degrees? Yes, over 20 and the rudder will come out of the water and the boat will round up.

I'm sure each and every one of these things will contribute to weather helm, but, when it takes two hands to hold the rudder when going to weather, I think I need a pretty big change.

I think the 3rd gen rudder would be fine if it were a few inches longer. I think I'll try this and, if that doesn't work, I'll try an Ida Rudder.

After thinking about it, I'm not absolutely sure that I have a third gen rudder. The prior owner said it was, but?????? What distinguishing physical characteristic does a third gen have???

Edited by - JohnMD on 07/07/2006 11:56:09

Arlyn Stewart
Master Marine Consultant

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2980 Posts

Response Posted - 07/07/2006 : 15:28:40

John, the 1st and 3rd rudders are short enough to clear the ground while the boat is on the trailer. The 2nd would not unless it was a beaching rudder kicked back.

Measurements are <ol type="1"><li>st - 61"</li><li>nd - 75 1/2</li><li>rd - 59</li></ol id="1">
Remember that the 3rd at 17" is considerably wider than the 1st at a maximum of 12". The 3rd also is thicker giving the rudder more lift especially at slower speeds.

Note: the measurement for the 3rd is the water ballast version. The wing keel version is if I recall correctly about 10 inches longer and around 69". I think it is nearly seven inches shorter than the 2nd generation rudder to make it the same depth as keel. The 3rd water ballast as can be seen is a whopping 16.5 inches shorter than the 2nd.

Also for those following the thread, the third was never produced in a beaching rudder so if one has a beaching it is either the 1st or 2nd.

Is it possible that the seller of your boat suggested it had the latest rudder and honestly had no knowledge of the 3rd?

The 2nd is capable of producing aching amounts of helm torque, especially the beaching if positioned a little aft by a worn hold down system, but the blade was bad too. If you have the 2nd, then I fully understand the sore arms.

Edited by - on

Tom Potter
Master Marine Consultant

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1913 Posts

Response Posted - 07/07/2006 : 15:44:36

Arlyn,
Were there any changes to the WK rudder design over the years?

Edited by - on

Arlyn Stewart
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2980 Posts

Response Posted - 07/07/2006 : 15:45:59

Frank, your wing keel rudder is ten inches or so longer than that on a water ballast so comparing your rudders ability to hold your wing keel and that on a water ballast isn't comparing apples to apples.

The IDA rudder differs from the current Catalina 3rd rudder in that it is a high aspect ratio rudder (a longer thinner foil section).

High aspect ratio rudders suffer more stress and must be built carefully to handle the loads without breaking. There advantages are a better lift to drag ratio and of course a deeper blade that doesn't suffer great quantities of rudder area loss when the boat heels.

There disadvantages are they may be lower than a keel and suffer damage during a grounding and they produce less control at slower speeds and aren't as good for docking.

Edited by - on

Arlyn Stewart
Master Marine Consultant

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2980 Posts

Response Posted - 07/07/2006 : 16:42:08

Tom, yes of course. The wk experienced the same evolution of rudders as did the wb.

It is helpful to understand that all the producers of water ballast hulls got caught flat footed with inadequate rudders. Using old rudder percentages they just didn't realize that a hull designed for interior ballast with more hull form stability would require greater control needs when heeling at greater angles.

A lot about marine design was/is experential.

Also interesting is that initial complaints about the control issues of the 250 and other wb models were blamed on water ballast as a ballast medium. Also, remember that the 250 was designed to be a wb boat... it wasn't produced in a wk until after more than 200 were built and sales were stagnant and the wk was produced to save the design and cure the handling problems. Catalina jumped right into the wk fray with a tall rig with a 150 genoa and got taken to school.

Learned very quick was the problem wasn't water ballast but rather the hull form needed for interior ballast. Such a hull form produces lifting forces from the asymmetrical footprint that when unbalanced to the CLR throw the boat into a yaw. Catalina got caught and the only thing they could do was to remove the tall rig and 150 from the options and urge everyone to, "sail it flat".

It was then that serious attention was given to why the boat was yawing excessively, if it wasn't water ballast then what was it? So, in a sense, it was the wing that saved the water ballast by getting the blame off.

To help illustrated what was to blame, understand that the 250 is one of few sailboats that has a net decrease in weather helm when trimming the bow down to her lines. The reason is that trimming the bow down to her lines moves the lift center of forces imposed by the asymmetrical footprint brought on when heeling closer to the desired center of lateral resistance and lessens the yaw force caused when that lift force is far from the CLR balance.

Most boats see increases of weather helm if trimming the bow down and if you want a real argument, go to the Precision forum on the Trailer Sailor and suggest to them that trimming the bow down can on some boats decrease weather helm and watch the reaction.

They will argue that trimming the bow down increases weather helm and they are correct as doing so moves the CLR forward and reduces the yaw damping effects of an aft CLR. What they don't grasp is a net effect... in other words, if trimming the bow down moves the CLR forward and increases weather helm by a factor, but moves the asymmetrical lift center point more to proper balance reducing yaw forces by a factor, the net effect can be a reduction in yaw forces and is infact true for the 250.

Most sailboats don't suffer the asymmetrical lift balance issue as much as the 250 bacause they first don't have a hull form designed for maximum form stability and they may be more fortunate to have an asymmetrical lift center naturally closer to the CLR balance.

Heck, its only been in the last few years that asymmetrical lifting forces have been recognized to play a part and the definitions of sailboat balance have been altered to include them.

Those who have given attention have done some rather interesting things. In the remote control one meter designs... the winners are now hull forms that have a heeling asymmetrical footprint that yields a lifting force to weather rather than the tradional leeward lift.

Again...more than asked for but perhaps interesting.

Edited by - on

britinusa
Web Editor

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USA
5404 Posts

Response Posted - 07/07/2006 : 20:54:56

Arlyn, I think I actually understood what you said. Not because of what I know, but because of the way you said it. Thank you.

From your description, I would assume that adding an additional water tank into the V berth storage area would reduce the tendancy to yaw to wind?

(Or did I not understand it

)

Paul.

Edited by - on

atgep
Master Marine Consultant

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1009 Posts

Response Posted - 07/07/2006 : 21:11:57

On my 25, (not the same) Shortening the forestay by a half inch got rid of my weather helm and turned my boat into one that will sail itself for a long way on its own.

Tom.

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ABYON
Deckhand

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Canada
11 Posts

Response Posted - 07/11/2006 : 12:18:11

I installed an IDA kick-up rudder this Spring on my 2003 250 water ballast with wheel steering. IDA added 3 extra inches to their standard length at my request.

I found IDA to be very helpful and responsive. The product is of very nice quality.

I find my boat's handling has much improved whether under sail or power. The tendency to round up has been much reduced but not eliminated (It is my experience that any boat pushed beyond a certain limit will round up). I do feel we have a lot more control and manoeuvrability.

On another topic. I bought my boat new and have grown to love it. This forum is wholly responsible for saving my nautical relationship. If it had not been for the amazing advice I was able to glean from this site, I think all of the irritants associated with owning a boat would've quickly soured me on the 250. Thank you.

Edited by - on

raulpou
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144 Posts

Response Posted - 07/11/2006 : 17:57:55

Did they charge you extra? What was the reason behind the added length?

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ABYON
Deckhand

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11 Posts

Response Posted - 07/12/2006 : 10:09:16

No extra charge. In fact, it was their suggestion.
No fancy theories behind the extra length. It was based on my "seat of the pants" observation that the original rudder (3rd generation)was way too short. I could see it almost breaking out of the water anytime the boat heeled significantly or if we were in larger following seas. I figured no matter how well designed a rudder may be, it's not going to work if it's not in the water. I don't know if the extra inches were actually needed but I have no complaints so far. My wife feels she has better control at the helm. I feel the boat can be pushed harder. And, at low speed, docking manoeuvres are more predictable.

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ABYON
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Canada
11 Posts

Response Posted - 07/12/2006 : 10:20:07

Just another quick comment. Our second time out with the new rudder we recorded our best speed ever... 6.9 knots. Our previous best was 6.3. This is our fourth season with the boat. Could be a lot of things but my feeling is that it is, in great part, attributable to the rudder and the extra confidence it's given us.

Edited by - on

raulpou
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144 Posts

Response Posted - 07/12/2006 : 17:20:44

Did you have to do any modifications? Also, who did you talk to about the added length?

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Arlyn Stewart
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2980 Posts

Response Posted - 07/12/2006 : 20:26:28

To exceed hull speed of 6.3 knots, several factors have to come into play... one of them is having minimum drag. A high aspect ratio rudder like the IDA will have less drag than the thick foiled Catalina 3rd.

It may not have as good of slow speed docking control however.

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raulpou
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144 Posts

Response Posted - 07/13/2006 : 06:54:04

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Arlyn Stewart
 To exceed hull speed of 6.3 knots, several factors have to come into play... one of them is having minimum drag. A high aspect ratio rudder like the IDA will have less drag than the thick foiled Catalina 3rd.

It may not have as good of slow speed docking control however.
<hr height="1" noshade id="quote"></blockquote id="quote">

Arlyn,

I understand the concept but by adding length, does that compensate for thickness? I thought that by being so long one would compensate for the other. Obviously I base this on "hunch" not scientific knowledge.

Edited by - on

ABYON
Deckhand

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Canada
11 Posts

Response Posted - 07/13/2006 : 10:39:41

No modifications as such. Just bit of drilling in the rudder itself. The rudder arrived with the gudgeons pre-installed. But since I have wheel steering, I had to drill six holes to install the plate that connects to the steering arm. I also drilled a seventh hole for the emergency tiller.

As for the extra length, this came as a result of a conversation with Joel at Idasailor. I knew my 3rd generation rudder was woefully inadequate. I also suspected from observation that it was mainly due to the short length. So in looking for a replacement rudder one of my principal considerations was a significant increase in length. It's also a significant expense. I didn't want to do too much experimentation and my gut was telling me the control problems we were experiencing were mainly due to the fact that there wasn't enough rudder in the water under certain sailing conditions. When Joel sensed my concern he said that he thought their rudder as designed would perform well. But he added that he could make it about 3 inches longer at no extra charge. My gut told me to go for it so I ordered the rudder with the few extra inches.

My observations are subjective of course. But they are supported by my wife who takes the helm as often as I do.

Edited by - on

JohnMD
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USA
207 Posts

Response Posted - 07/13/2006 : 11:34:23

I think you've convinced me. I was thinking about adding a few inches of glass to my 3rd gen rudder. I think a new IDA would be much nicer. I'll probably have to be really nice to the wife for a while.

Do you have any guess as to how much past the keel the rudder sticks down? I guess it really doesn't matter tho, it is a kick up. Thanks for all the good info.

Edited by - on

Arlyn Stewart
Master Marine Consultant

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2980 Posts

Response Posted - 07/13/2006 : 12:12:42

Raul... high aspect ratio foils are thinner, longer and have less chord...and wont suffer as much rudder loss when heeling as a short, thick large chord rudder. But... it is not just the square inches that massage the lift ratios... a thicker foil produces more lift at slower speeds than does a thin foil... but the thick foil also produces great amounts of drag at higher speeds. Everything is a trade off.

If I were sailing on a docile lake and lived in a slip that required intricate manuvering to get in and out of... I'd want the thicker foil. However, if I were racing or sailing aggressive venues demanding maximum control... I'd want a high aspect ratio foil deep in the water.

Edited by - on

ABYON
Deckhand

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Canada
11 Posts

Response Posted - 07/13/2006 : 14:30:03

I have the water ballast version with swing keel (5'9" of draft) so the rudder does not go deeper than the keel. But you're right. With a kick-up rudder you should have no problem. IDA delivered the rudder with a nylon breakaway bolt for the pivot point (actually they also included a spare). So far it's performed flawlessly.

Edited by - on

raulpou
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144 Posts

Response Posted - 07/13/2006 : 16:13:30

I am also convinced. I will give Joel at IDA a call. Thanks so much for the info!

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