Foss foam rudder install

Kwehemef · July 25, 2022, 08:43:16 AM

Hi all,
We installed the new Foss foam rudder on our 1988 c34, not the elliptical. Has anyone done the same? Our boatyard did the install. I am wondering what to expect from the install results. Has anyone also installed the new Foss foam rudder on their mk1 wing keel 1988 c34? Please see attached photo.

Ron Hill · July 25, 2022, 02:00:15 PM

Kwe : It looks to me like you did get the new style elliptical rudder. I say that because the rear of the original rudder is a straight line from the top to the bottom. Yours is an elliptical curve!!!

A thought

Ron Hill · July 25, 2022, 02:14:39 PM

Kwe : I say you have the new elliptical rudder, because I made my own by scabbing on an addition piece on to the trailing edge of the old style rudder.

If you want to compare - just look at my Mainsheet tech note article that I wrote - w/pictures; where I show how to make your own elliptical rudder out of the original rudder !!!

A few thoughts

Ron Hill · July 25, 2022, 02:51:23 PM

Kwe : You asked "what to expect?" In my article I found that there was NO more uncontrolled "rounding up into the wind" while beating. However, with the added surface on only the trailing edge of the rudder, expect it to be a bite "heavier". As I point out in my article Catalina compensated for this in the MKII by installing a larger wheel for more mechanical advantage!!!

But, you'll enjoy the better rudder control especially with your wing keel. Don't believe that the elliptical change is so noticeable if you have a C34 fin keel rudder.

A few thoughts

Stu Jackson · July 25, 2022, 08:48:27 PM

Quote from: Ron Hill on July 25, 2022, 02:51:23 PM

...................

Don't believe that the elliptical change is so noticeable if you have a C34 fin keel rudder.

I DO believe. I'vementioned this before, but in two boats - my 86 and Dave Davis' #707, an 88 - there is a remarkable difference in two identical boats with deep keels.

When Dave "let me drive" his boat after he'd installed his new rudder (in maybe 2005), the difference is/was like regular automobile steering compared to power steering. Kinda like night and day.

Not that anybody here ever drove a car without power steering...:):):)

Ron Hill · July 26, 2022, 02:27:51 PM

Stu : Thanks for the updated info. That's the first I heard about the elliptical rudder performance on the fin keel.

I knew that the fin keel old rudder didn't have the uncontrol-able round up into the wind problem that the wing keel had. Just not enough rudder in the water when heeling!!

A few thoughts

Noah · July 26, 2022, 02:36:09 PM

MK1 fin keel with OEM rudder still does round-up if over canvassed.

Ron Hill · July 27, 2022, 09:23:04 AM

Noah : The problem with the wing keel and the original rudder is that you could become "over canvased" at just over 16kts of wind!!! When the hull heeled and the bow lowered there just wasn't enough rudder in the water!! You could NOT hold the boat from heading up into the wind!!! A tightened boom vang (flattening the main) helped!

A thought

Noah · July 27, 2022, 10:48:05 AM

16 kts. is about 1st reef time on my fin keel boat for the same reason.

Ted Pounds · July 28, 2022, 01:02:13 PM

Quote from: Stu Jackson on July 25, 2022, 08:48:27 PM
Quote from: Ron Hill on July 25, 2022, 02:51:23 PM

...................

Don't believe that the elliptical change is so noticeable if you have a C34 fin keel rudder.

I DO believe. I'vementioned this before, but in two boats - my 86 and Dave Davis' #707, an 88 - there is a remarkable difference in two identical boats with deep keels.

When Dave "let me drive" his boat after he'd installed his new rudder (in maybe 2005), the difference is/was like regular automobile steering compared to power steering. Kinda like night and day.

Not that anybody here ever drove a car without power steering...:):):)

Same thing on my fin keel, noticeable improvement. Also on the fin keel version the elliptical rudder seemed slightly better balanced than the original. That's probably because instead of adding area to trailing edge they added area by making the rudder deeper...

Ron Hill · July 28, 2022, 03:18:29 PM

Guys : If you look back into the Mainsheet Tech Notes of Nov 1998 for the fin keel rudder and May 1999 for the wing keel rudder; you'll find an overlay drawing of the new over the old rudders. I had asked Jerry Douglas for those drawings so all could see the differences and published them in those issues of the Mainsheet Tech Notes.

Re examining them I see that the fin keel elliptical added BOTH depth (7 inches) and some width (3.375 inches at the bottom tapering from 0 at the top) with no added surface infront of the SS column (pivot point)

Re examining the wing keel elliptical ONLY added to the surface width (5.7 inches at the bottom tapering from 0 at the top ) with no added surface infront of the SS column (pivot point) I'm sure that adding depth to the new wing keel rudder would have made the rudder deeper than the keel!!!!

That is why I said that the wing rudder on the MKI would be a bit heavier because on the MKII the wheel was much large for a better mechanical advantage. Now I can see the the fin keel had much better handling because it has 7 more inches of rudder in the water!!

A few thoughts

Noah · July 28, 2022, 03:46:00 PM

I want one! But am out of refit steam.

Ron Hill · August 02, 2022, 02:48:47 PM

Noah : Why don't you do like I did. When I was on the hard one winter I made a cardboard pattern from another wing keel C34 new style rudder. Then I added a scab-on piece to my old style rudder. It wasn't that hard to do. I wrote up a detailed "How To" for the Mainsheet tech notes with detailed pictures.

My 1st Mate was really worried!! She said "What if your Scab On piece comes off"!! My reply was simple - "You still have the original rudder"!!!

A few thoughts

Noah · August 02, 2022, 04:24:30 PM

Ron-it is a thought. But, I wouldn't get the benefit of the elliptical shape and improved foil/balance. My next haul-out is in 2 years, so I have time to think on it and time to hide more funds from my wife

Ron Hill · August 03, 2022, 02:39:57 PM

Noah & Any MK I C34 Fin Keel owners : I made my own elliptical rudder.!! All you do is find a fin keel C34 with a elliptical rudder MK ! or MK !!. Take some cardboard and make a tracing of that rudder. Then put it against your original fin keel rudder and you can see the elliptical add on piece that you can make. Follow what I did in my Mainsheet tech note article and you can made your own elliptical rudder!!!

If you look at the rudder overlays from Jerry Douglas that I published in the Mainsheet tech notes - you will see that NOTHING was added in-front of the pivot SS rudder column!! All added surface was aft!!

I commented that mine is heavier because substantial was added for the wing rudder and as I mentioned the new (then) MK II wing Keel has a larger 44" (I believe that's the size?) Edson wheel for better mechanical advantage!! Where as the The MK I boats MIGHT? only be able to go up to a 36" wheel (from 34") because of the cockpit configuration in the MK I.

A few thoughts