New Rudder Oversized?

Ron Hill · July 09, 2019, 02:43:44 PM

Dukes : WOW !! Ken has included my pictures of my modification of my original 1988 wing keel rudder to Catalina's new elliptical wing keel rudder. You might want to look in the Mainsheet tech notes and read my article.
Your rudder is going to be so heavy that it's going to be near impossible to control. Definitely get CD to take it back and send you the correct one. Way too much surface behind the pivot point. I pointed out that with the new elliptical rudder on the MkII C34, Catalina even increased the wheel up to 42" just to take care of the heavier rudder (more purchase)!!
Don't believe I have to say anything about the 3 inches longer (deeper) than the wing keel - do I? Grounding by rudder first!?!

In another Mainsheet Tech note article I have an overlay drawing of the OLD and the NEW wing keel rudders (also the fin rudders) to send to Catalina Direct so they can see their screwup! Jerry Douglas sent the drawings to me.

Just looking at your picture I also see that you do NOT have a Catalina 3 bladed Sailor Prop!!! Looks like you have a Michigan Wheel with a much larger cord surface area!! Don't know the pitch nor diameter, but it may be a large load on your engine!! Something else to check.

A few thoughts

KWKloeber · July 09, 2019, 09:22:33 PM

Quote from: Ron Hill on July 09, 2019, 02:43:44 PM

Your rudder is going to be so heavy that it's going to be near impossible to control.

Just a guess but I'd bet the HDPE rudder, though larger, is a no heavier and likely lighter than the CTY fiberglass rudder!

Dan, did Ken quote the different weights?

Ron Hill · July 10, 2019, 12:40:33 PM

Guys : When you add more surface area behind the pivot (rudder column) of the rudder with the same amount of surface in front of the pivot - the heavier the rudder gets!! Simple Physics!!

I'm not talking about weight

, but force needed to control the wheel steering!!

They must have added surface area before the pivot to counteract the much larger added surface behind that pivot or it would be almost impossible to steer!!

However, there is still an BIG issue if that rudder is really 3 inched deeper than the keel!

A thought

glennd3 · July 10, 2019, 02:18:37 PM

I have the same rudder as Dan on my boat. Previous owner installed in 16. I have no weather helm compared to my 30. I looked and cannot find a picture but it extends past the hull and is basically rectangular. I have no problems with it.

Noah · July 10, 2019, 02:51:48 PM

Glenn- does it extend aft of the skeg as well? Hmmm? Glad it sails/handles OK. However, if it was me, I would be concerned that it extends below the keel, which in my opinion, increases the chance of damage in groundings—even light ones.

glennd3 · July 10, 2019, 04:39:15 PM

It does extend beyond the skeg, but not deeper the keel. Previous owner was very happy with the change in performance, says wife , he has passed. I will also say that I back into marinas,slips and it turns on a dime when backing. In the first picture on this thread I think the photo makes it look longer than it is, mine extends beyond the skeg but if you are not really looking you would not notice. Like buying a new car you never see one on the road till you buy one and then you see them everywhere. I will look at it this weekend and try to see how far it extends.

Jon W · July 10, 2019, 05:01:59 PM

If possible it would be interesting to see a photo of your new rudder to compare.

Noah · July 10, 2019, 05:57:10 PM

Glenn and Dan- Dan said his rudder "extends 3 inches below the wing keel" and it looks to extend at least 6 inches aft of the skeg. So, It sounds different (larger) than Glenn's.

Sdsailor · July 10, 2019, 06:05:41 PM

Glenn that's good news that your performance did improve. Thank you. I went to the shipyard to retrieve my old rudder but it was cut up and tossed last week. No matter though, as my old rudder post was bent and as a result, the top of it had to be cut away to make it home. My plan at this point is to tune the rigging, get the new sails on this weekend and give it a whirl. Not sure how much I'll be able to determine in 7knots or wind. Thanks for everyone's input!

Noah · July 10, 2019, 06:27:50 PM

Dan—I believe Glenn has a different size rudder (smaller?) as he says it doesn't extend deeper than the wing nor far aft of the skeg. Also, to clarify, Glenn bought his boat with his current "rectangular blade" rudder installed by the PO, and has only sailed his boat with this rudder—so he has no way to compare it to the original Catalina rudder or judge performance change—only the hearsay of the PO's widow. On the plus side, Glenn says his boat sails very well and he is happy with the performance, so you may be with your new rudder too. However, if you don't like it and you ordered the elliptical rudder and instead CD sent you the RudderCraft rudder—then you have recourse to reject it.

glennd3 · July 11, 2019, 05:37:16 AM

Quote from: Jon W on July 10, 2019, 05:01:59 PM
If possible it would be interesting to see a photo of your new rudder to compare.

I looked for a picture while on the hard, could not find one as I purged some from my phone and the one I did have had a car in the picture that blocked a view of the rudder. I will be at the boat this weekend and I believe I can get a picture of the top of the rudder in the water.

Steve_in_lex · July 11, 2019, 06:42:33 AM

Our PO got the CD rudder so I haven't used anything else. It looks weird but seems to steer fine. Reverse is often a problem. Picture attached.

Ben H. · July 11, 2019, 07:26:24 AM

For reference, back in in 2016 I installed a new rudder that I purchased Direct from Catalina Yachts. I believe at the time their quoted price was better the CD. The PO had broken off the original rudder. Here is an image of the new rudder installed.

Ron Hill · July 11, 2019, 02:11:08 PM

Steve : Your rudder doesn't look deeper than the keel!?!

glennd3 · July 11, 2019, 06:04:32 PM

https://www.catalinadirect.com/shop-by-boat/catalina-34/hull-deck/stern/rudders/rudder-c-34-c-36hdpe-unifoil-wing-keels/

I looked at CD website I believe I have model 8036 HDPE which states the following, which I believe is what I am experiencing when sailing. I do not fight the wheel, easy to sail.

Our Catalina 34 and Catalina 36 rudder's balanced shape moves the center of effort of the rudder forward for a lighter helm. This rudder offers a vastly improved shape you can see when compared to the original Catalina 34 and 36 rudder's. It is an NACA (National Advisory Committee for Aeronautics) 0012 airfoil considered by many sailboat designers to be the ideal combination of maximum lift with minimal drag.

I did some searches for 0012 airfoil but got caught in a physics lesson!