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Question on Balanced Rudder

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SKS
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Initially Posted - 10/05/2015 : 11:24:09

I've seen the drawings on the Balanced Rudder.
Intuitively, it makes a lot of sense to have some of the rudder area ahead of the pintles so that the rudder action is more balanced.

I don't, however, understand the weird shape.
Why are there odd angles to produce the area in front of the pintles.
Wouldn't it be easier to build with a simple straight section ?

Am I way off base here ?

"Lady E" 1986 Catalina 25: Fin Keel, Standard Rig, Inboard M12 Diesel, Sail No. 5339
Sailing out of Norwalk Cove Marina, Connecticut

Stinkpotter
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Djibouti
9013 Posts

Response Posted - 10/05/2015 : 11:46:05

The way they make blade area forward of the pintles on a transom-hung rudder is to make a "step" that extends part of the blade under the skeg at the rear of the hull. On some balanced rudders, you see two steps--one extends the upper part just below the pintles down to the skeg. The lower step entends the blade forward under the skeg. I suspect the slight rearward angle of the leading edge under the lower step is intended to cause the balancing section to be more toward its top so it applies less leverage against the lower pintle. There's no need for the balanced area to be equal all the way to the bottom of the blade.

Conventional wisdom is to have about 15% of the area forward of the invisible pivot line. Thus, the rudder is not totally "balanced"--it retains some centering force (when moving forward), but less than with a rudder with no balance designed in.

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

Edited by - Stinkpotter on 10/05/2015 11:54:40

SKS
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Response Posted - 10/05/2015 : 11:55:15

Thanks for your quick reply.
I guess the part I don't understand is why have two steps to produce the 15% area instead of a single step.

I may just go ahead and buy the rudder from Catalina Direct. At $648 dollars, it's a bit pricey, but if I take into account the cost of the wood, glass and my time, maybe not so much. The HDPE rudder has a single step.

I see Ruddercraft has one for $689, including new pintles. Lots of options.

How do I paint the HDPE ? I'll need some anti fouling paint, but do I need to prepare the surface in a special way ?

"Lady E" 1986 Catalina 25: Fin Keel, Standard Rig, Inboard M12 Diesel, Sail No. 5339
Sailing out of Norwalk Cove Marina, Connecticut

Edited by - SKS on 10/05/2015 11:58:50

islander
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Response Posted - 10/05/2015 : 13:54:56

quote:
How do I paint the HDPE ? I'll need some anti fouling paint, but do I need to prepare the surface in a special way ?

I'm not sure you can. Their claim is that HDPE is like Teflon and nothing will stick to it. My opinion is that if you stick it in the water for long enough, Critters will get a foot hold somehow. Some on this forum have said that the HDPE rudders flex when pressed hard. Others have said they love it. I do like the idea of being solid and never soaking up water. The fault in the Catalina rudders is that they rely on a thin fiberglass shell to give them structural strength. Most of the forces on the rudder and where they usually break occur around the lower pintle. I think over time the fiberglass shell starts to delaminate from the foam core from water intrusion or just plain heat from the sun or age and the rudder loses its strength then snaps. IMO there should be a SS rods/grid in the foam to give it extra strength through the pintle area. Just to show how much pressure is exerted on the lower pintle, This is what happened to my balanced rudder.

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

SKS
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Response Posted - 10/05/2015 : 14:40:36

Interesting photo.
It makes me wonder if maybe I should think about redesigning a balanced rudder myself.
From what I see, if the standard rudder has 100% of the area behind the pintles, then a balanced rudder has 15% in front of the pintles. The result is 115% of the area, and therefore 115% of the stress, resulting in ripped pintles.
Maybe a rudder designed with 15% ahead of the pintles and 85% behind the pintles might be better.

"Lady E" 1986 Catalina 25: Fin Keel, Standard Rig, Inboard M12 Diesel, Sail No. 5339
Sailing out of Norwalk Cove Marina, Connecticut

Stinkpotter
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Djibouti
9013 Posts

Response Posted - 10/05/2015 : 16:15:10

It's probably about 85-15%. Notice in Scott's picture that the upper step is just below the pintle but still behind the transom. The lower one is below the waterline and reaches under the skeg. If you make your own, I suppose a single step reaching under the skeg would suffice, although two shorter steps might have a structural advantage.

I have seen/heard reports of HDPE rudders snapping--they might be less tolerant of bending under extreme stress than the foam-cored fiberglass, which is what I had (from CD). Most breaks have been with the early unbalanced blades, which have wood core in the "head" down to the lower pintle, and are solid (I believe) below that. Those two sections are easy to recognize. The head often absorbs moisture, splits from freezing or whatever, rots inside, and then breaks off at the lower pintle in strong wind and chop.

CD warns buyers of the foam/fiberglass rudder not to leave it out of the water exposed to sun against bottom paint on the blade, which can cause the foam to expand and split the fiberglass. When my boat came out for the winter, the rudder came home and lived in the basement.

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

Edited by - Stinkpotter on 10/05/2015 16:17:31

islander
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Response Posted - 10/05/2015 : 16:39:42

As Dave said, most of the broken rudders are the earlier models. Now is that due to age? Will the balanced rudders do the same when they get that old? Are we expecting them to last forever? I don't know. I Do believe that another weak link in the design is having that step right under the lower pintle making the rudder smaller in the area you want strength. On top of that you drill two holes in that area weakening it further. The straps could be longer and wider to spread the load over a larger area also.

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

Stinkpotter
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Djibouti
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Response Posted - 10/05/2015 : 20:54:14

quote:
Originally posted by islander

...I Do believe that another weak link in the design is having that step right under the lower pintle making the rudder smaller in the area you want strength...

??? How else do you create the balancing area that projects forward of the pivot line through the pintles?

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

OLarryR
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Response Posted - 10/06/2015 : 03:37:31

I have an '89 with a balanced rudder. My opinion is that since it has lasted now for 26 years (in the water all year-round for the past 10+ years and also same with the PO) and without problems and considering this is a boat part constantly used with stress and fatigue, my efforts would be to go after something else that is not as reliable to potentially improve. After 26 years, other components need attention such as the outdated switch panel causing many to bundle/gang wires combined onto same switch - Many have installed new switch panels with more switches and relocated panel in more convenient locations than say under the steps. Outboard motor brackets were originally designed for lighter 2 stroke outboards and so many are now installing 3 and 4 spring brackets. Stays get changed out after 10-20 years or at least should be ....but I have not seen any stays advertised to last a lifetime or recommended to last ~26 years (though) probably some have them on that long. Sails - Many buy sails that are on the low end cost made with less thread count, less stretch resistant Dacron versus higher thread count, low stretch Dacron sails that do not blow out as quickly as the original sails (though all Dacron sails seem to last a long time before actually tearing but the lower quality sailcloth loses it's shape, depending on use, in as little as 3-4 years). Mast wiring and anchor lights eventually fail and that is prime for an improvement - Replacing wiring and perhaps going with a photo-diode LED anchor light.

My general philosophy is that if I get what I consider good life/reliability/service out of a product, I tend to want to go back to that same product/mfr again when I need a replacement. Since my balanced rudder has lasted so long, still going strong and still functions satisfactorily, when it does need replacement, I would want to ideally replace it with exactly the same manufactured rudder and I believe there are at least 2 mfrs that make replacements very similar in configuration and construction to my '89 balanced rudder.

.....Now...getting off my soap box.... owning a sailboat is like a hobby. Many of us enjoy working on the boats perhaps as much as sailing (well...maybe not as much as sailing). But many of us like to make improvements and many of us derive satisfaction out of doing these improvements ourselves. So, in that vein, I can definitely see the interest in designing one's own rudder with goal to making it an improvement over the existing one. (But you have to admit - Getting 26+ years out of any product seems pretty good !)

Larry
'89 Robin's Nest#5820, Potomac River/Quantico, Va
http://catalina25.homestead.com/olarryr.html

Edited by - OLarryR on 10/06/2015 03:50:22

mrapkins
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Response Posted - 10/06/2015 : 05:00:24

As I have said before, in addition to the rather poor design of the rudder itself (thin shell around foam) the reason the rudders break/fracture is because the pintle is too small. All the force on the rudder (remember desperately trying to hold the tiller as your boat rounds up) is on the tiny pintle. I had my pintle made longer when, upon more reflection, I should have added sections vertically to spread the load.

More structure inside the rudder would help but look at the size of that pintle!!

Edited by - mrapkins on 10/06/2015 05:34:50

islander
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Response Posted - 10/06/2015 : 06:51:00

quote:
How else do you create the balancing area that projects forward of the pivot line through the pintles?

Dave, I'm not an engineer but I do know that having a corner creates a stress point. If I had the resources to build a foam core rudder I would radius that corner or have that leading edge slant out gradually from that corner down to the second step that goes under the skeg. Then foam in a SS grid with vertical rods in the front 1/2 of the rudder extending from the head to 2/3 the way down. Larry has a point, 30yrs ain't bad for something to last but if an improvement can be made then why not. Also when I was repairing my broken pintles the foam inside the bolt holes did not appear to be high density but rather a lower density. Also if it soaks up water then its open cell,Not closed cell. Probably to save $$$ in production.

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

Edited by - islander on 10/06/2015 07:22:34

Stinkpotter
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Djibouti
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Response Posted - 10/06/2015 : 07:58:55

The characteristics of the foam might be chosen to keep it from exploding the shell as it cures. I doubt that its cost is significant in a $600+ rudder. SS grids are common in big-boat rudders--just one of those factors behind big-boat prices. Another potential weak spot, if you want to look for them, is the lower gudgeon, which is screwed into a small threaded bronze plate that's embedded in the fiberglass. Others are the fore and aft chainplates, particularly on the earlier models... (There was a picture here of one that ripped off the bow.) As discussed here many times, she wasn't built for sailing over the horizon like a Cape Dory or Pacific Seacraft, didn't cost like one, and still doesn't. (Check listings for mid-'80s Dana 24s.)

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

awetmore
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Response Posted - 10/09/2015 : 14:14:23

I had the Ruddercraft HDPE rudder on my C-25 (Catalina Direct sells it too). I had the normal one, not the heavier "blue water" one.

I wouldn't buy that rudder again. It has too short of a chord length, so it stalls very easily. The rudder is more flexible than fiberglass ones and has a funny flutter in the water when the boat is moving fast that I've never felt with other rudders.

I did use bottom paint on it (Pettit Unepoxy) and that worked just fine.

Alex W
Seattle, WA
Express 37 "re-Quest"
previously owned 1984 Catalina 25 "Lutra"

SKS
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Response Posted - 10/09/2015 : 15:15:03

Sounds like the Blue Water design is the best.
A little more money, but stronger. Am I right, the Blue Water rudder is also balanced ?

"Lady E" 1986 Catalina 25: Fin Keel, Standard Rig, Inboard M12 Diesel, Sail No. 5339
Sailing out of Norwalk Cove Marina, Connecticut

bigelowp
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Response Posted - 10/09/2015 : 19:23:47

I have had the HDPE balanced rudder since 2007. Yes, it needs bottom paint. Yes, the paint wears faster than on the fiberglass bottom. I have not had any issues regarding it breaking/bending/etc. And it, at the time, was truly turnkey and whittler looks great. SKS -- I will be hauled this week at NCM so you can see it (and the rest of the boat) in person if you wish.

Peter Bigelow
C-25 TR/FK #2092 Limerick
Rowayton, Ct
Port Captain: Rowayton/Norwalk/Darien CT

awetmore
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Response Posted - 10/15/2015 : 09:26:50

quote:
Originally posted by SKS

Sounds like the Blue Water design is the best.
A little more money, but stronger. Am I right, the Blue Water rudder is also balanced ?

Personally I'd buy a fiberglass rudder from Foss Foam vs any of the HDPE rudders.

Alex W
Seattle, WA
Express 37 "re-Quest"
previously owned 1984 Catalina 25 "Lutra"

SKS
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Response Posted - 10/15/2015 : 18:48:17

quote:
Originally posted by bigelowp

I have had the HDPE balanced rudder since 2007. Yes, it needs bottom paint. Yes, the paint wears faster than on the fiberglass bottom. I have not had any issues regarding it breaking/bending/etc. And it, at the time, was truly turnkey and whittler looks great. SKS -- I will be hauled this week at NCM so you can see it (and the rest of the boat) in person if you wish.

Thanks Peter. I saw your boat tonight. Very nice. You take your mast down for the winter ? NCM must cost you a fortune !

Steven

"Lady E" 1986 Catalina 25: Fin Keel, Standard Rig, Inboard M12 Diesel, Sail No. 5339
Sailing out of Norwalk Cove Marina, Connecticut

DavidBuoy
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Response Posted - 10/16/2015 : 20:38:46

quote:
Originally posted by awetmore

quote:
Originally posted by SKS

Sounds like the Blue Water design is the best.
A little more money, but stronger. Am I right, the Blue Water rudder is also balanced ?

Personally I'd buy a fiberglass rudder from Foss Foam vs any of the HDPE rudders.

I love my Foss balanced rudder. Great people to work with and awesome quality. You do have to prep the rudder yourself and drill and mount the hardware which wasn't bad. Have to make sure to sand off all fiberglass release agent before barriercoating. I didn't do it well enough and had to redo it after one season, no worries though. Here's the original versus the Foss balanced:

Edit: photo won't post

Captain Rob & Admiral Alyson
"David Buoy"-1985 C25 SK/SR #5053

Edited by - DavidBuoy on 10/16/2015 20:41:25

Ape-X
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Response Posted - 10/17/2015 : 04:53:03

don't sweat your choice, pick what speaks to you and don't look back. Put time into balancing your sailplan and sail trim which reduces stress on the rudder.

s/v No Worries, O'Day 28
PO Moe'Uhane - C25 SR/FK #1746

bigelowp
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Response Posted - 10/17/2015 : 06:22:17

Steven

Just go down to NCM during a blow in mid winter and listen to the wind in the rigging and then think about that over 30+years on a deck stepped boat -- I view removing the mast as cheap insurance as the standing rigging and deck should last longer -- plus I can inspect and make improvements if needed. Also reduced opportunity for water to seep through during winter under shrink wrap. Lok forward to seeing your's, hopefully this weekend.

Peter Bigelow
C-25 TR/FK #2092 Limerick
Rowayton, Ct
Port Captain: Rowayton/Norwalk/Darien CT

Stinkpotter
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Djibouti
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Response Posted - 10/17/2015 : 08:53:32

I stored Passage at NCM--they required taking the mast down at the time, and I appreciated being able to inspect the rigging on the rack and having the rigger set everything up the next spring. Periodically I'd go over to remove some snow from the cockpit, and on windy days, I'd marvel at the lashing poly-tarps on many boats--beating up the gelcoat, teak, etc... I figured if Passage could withstand rain in the summer, she could take some snow in the winter, as long as it didn't accumulate above the companionway threshold. The wind mostly took care of that, and my plastic children's snow shovel did the rest. She did get some puddles on the galley sole, but she was in better overall shape when I sold her than when I bought her.

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

islander
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Response Posted - 10/17/2015 : 13:44:30

quote:
I figured if Passage could withstand rain in the summer, she could take some snow in the winter

It's not that the boat can withstand rain in the summer, Covering the boat in the winter is to prevent melting snow from getting into cracks and crevices then re-freezing at night doing damage. C25 cockpit floors and the scuppers are known trouble spots for water intrusion so a cover can help stop the freeze, melt,Re-freeze damage.

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

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