foiled rudder

[CaptK]

A lil CP rudder history...

Used to be only a few guys with foiled rudders, and they'd made them on their own. The CP's sized from the 23 and down (this was pre-'Cats and Eclipse days) only came with a flat plate aluminum rudder. On top of the inefficient shape of the blade itself was the fact that almost all of the blade was positioned aft of the pintle axis, making it that much more difficult to steer (moving some surface area forward of the axis of rotation helps provide power to turn the blade when it is deflected).

Deflect that puppy more than a few degrees, and you could hear the stall burbling in your wake. On the CP23D that I had then, it really bothered me, especially when trying to make ground to windward. The fact was that I had a thing which turned my boat using drag, not lift, and it basically slowed me down constantly. Adding insult to injury, it was positioned so that it was almost as hard as it could possibly be to actually turn the rudder off center.

Having a background in composite construction (making surfboards and fixing boats), I decided to make my own foil to fix these design defects, and then get a friend of mine to make a mold from it, so that we could make them fairly easily, and available for other CP sailors. I used software to make the proper foil shape of the proper size, and then made a couple different prototypes of the profile shape of the rudder (to position CE more forward). The testing of these went well as far as the efficacy of the foil - though my prototype construction failed quickly, as expected - it was just 'proof of concept', anyway.

Buoyed by the test results, I constructed half-foils of pink foam covered in epoxy, planning to bond the two pieces to my flat plate rudder with adhesive. I was in the process of fairing the foil halves when Joel from Idasailor started inquiring to the CP Yahoo group about what kind of market there might be were he to produce a foiled rudder. I contacted him and told him of the work I'd done, and we began working together.

Using the foil shape and design dimensions I'd come up with, Joel made the first CP foiled rudder to be constructed of HDPE with an aluminum 'spine'. I bolted it onto my boat, and it worked great, except for one problem - he'd used aluminum plate that was CP16 blade thickness, and my 23 bent it during a hard day of sailing in 20 kt winds. Not much of a problem, that! Fixed in rev. 2 , and with a couple more small improvements, CP's now had a great source for a tough, nice solution to the flat-plate rudders that they were shipped with.

And that's how it happened. If you have been using a flat plate, you'll notice an *immediate* difference when you go to a foil. I think it also bears pointing out that newer small CP's are now getting foiled rudders from the factory - cool!

One huge advantage of the IdaSailor rudder that I'd like to point out too is how extremely easy it is maintenance-wise. The HDPE is way tougher than a foam-core composite FRP rudder that I would have had my friend build, and the HDPE is also very easier to keep clean, even when it has been left in the water long enough for marine flora and fauna to have colonized it. Add to that the fact that Joel and the other folks at IdaSailor are very nice and customer-happiness oriented, and it's a win-win situation to upgrade your old rudder to this newer solution.

[Paul]

Hey CaptK!!  Great to hear from ya!  WOW, I never new your link to the Idasailor rudder.  A hardy thanks for your contributions and a pitcher of grog to ya!!

[Rick Klages]

If I had waited for CaptK I could have saved some typing!  Bravo job on the rudder!

ick

[Gil Weiss]

Joel wants me to buy the flip up w/hydraulic strut version for my CP19. It replaces everything and includes a new wood tiller.

Has anyone used the new version yet?

Oldgoat

[Craig Weis]

CaptK

Thank you very much. I have the 'foil' and think the world of it. I talked two cp'ers into purchasing that rudder after each test sailed mine on Comfort & Joy.

[Ralph Erickson]

Gil, In addition to Joel, I want you to buy the flip up w/hydraulic strut version for your CP19 too.  Then I can see if I want to buy one too! 

Ralph

[CaptK]

The new version sounds even better! It was always a chore to keep the rudder out of the water when I wanted to store it 'up', using a line - seemed like a last few inches of the top of the blade always stayed in the water, and it was difficult to even get it that far. The hydraulic assist sounds like a good addition. Go for it, Gil!

I forget who it was who first posted about foiling their rudder way back when, but by the time I did what I did several people had done so, with good results. *Those* are the people who deserve the thanks!

Without them, who knows how long CP sailors would have gone around dragging flat plates through the water?

[idouglas]

Thanks Capt:

I keep my CP16III/XL on a mooring in the ocean and as you say: the last few inches of my IdaSailor rudder still rests in the water, even in the fully up position.  Without antifouling paint, the plastic rudder is a great host for all sorts of green slime and other living things like barnacles. 

To avoid having to scrape the rudder clean once a week, I'm thinking of grinding down the top one inch or so of the metal  blade where it attaches to the rudder so that I can pull the thing completely out of the water. 

My question:  does anyone have any experience with such a retrofit to the IdaSailor?

Thanks.  idouglas

[Rick Klages]

Notching the back of the rudder plate is not a bad idea.  If I end up mooring next year I might consider that. Thanks for the idea!

ick

[CaptK]

Sounds like it would work, but - if I were you I would contact Joel at IdaSailor prior to doing that, and ask him if that would effect the warranty and/or strength of your rudder.

I used to move some heavy stuff forward before leaving the boat to get the stern up as high as possible.

Another idea: You might be able to duct tape a paint scraper to a short pole, and use that to scrape the rudder top from the cockpit fairly easily, if you can't get it out of the water all the way.

We use tile scrapers to hit the waterlines here. You can stand on deck or dock and reach far enough to knock off the bad stuff.

Just a thought.

[idouglas]

Capt. That's exactly what I wondered and so I wrote to Joel at IdaSailor.  Below is his response, including a note on warranty.  He's a good guy working for a good company.  idouglas

"Thanks for the kind words about the rudder, I'm glad that it is meeting your
expectations for quality and performance, your feedback is much appreciated.
I'm sure that removing some rudder core plate material would probably be a
good solution to the rudder raising dilemma. Another thought would be to
remove the pivot bolt, raise the rudder to the desired new position, then
mark the proposed location of a new pivot hole in the rudder's aluminum
core. (mark the new location through the rudderhead's pivot bolt hole)
Next, pivot the blade to the down/deployed location and see if the mark you
have made will work in the down position as well. If that is the case, you
may find that drilling a new pivot hole that will accommodate the full range
of movement fully up and fully down may be a simpler solution than grinding
away part of the rudder's aluminum core at the top.
Unfortunately, because there seems to be a lot of variation in the OEM
rudderhead castings, our parts fit a little differently from boat to boat,
some blades raise more fully than others.
I spoke with Hutchins about this and they told me that they had drilled the
aluminum flat rudders on a boat-by-boat basis and there was no real standard
on pivot hole location. This was a function of variation between rudderhead
castings as well.
Hope this helps, as long as any grinding takes place above the existing or
proposed new pivot hole, we don't have any issues with your modifications
affecting your IdaSailor rudder warranty.
Thanks again, let me know how your project goes."
-Joel
Joel Santarone
General Manager
IdaSailor Marine Inc.

[PhotoEd]

Just wanted to say that I got my Ida Rudder in yesterday and IT IS BEAUTIFUL!!

Can't wait to get her wet!

[multimedia_smith]

I got mine soon after I got the boat... definitely the best single improvement along with new sails.
Not that it's a big deal... but an added bonus is the fact that it has neutral buoyancy, so instead of adding weight to the stern... it wants to float!  Pretty Cool
Dale

[Bob P WHTMTS]

The new version sounds even better! It was always a chore to keep the rudder out of the water when I wanted to store it 'up', using a line - seemed like a last few inches of the top of the blade always stayed in the water, and it was difficult to even get it that far. The hydraulic assist sounds like a good addition. Go for it, Gil!

I forget who it was who first posted about foiling their rudder way back when, but by the time I did what I did several people had done so, with good results. *Those* are the people who deserve the thanks!

Without them, who knows how long CP sailors would have gone around dragging flat plates through the water?

Is the Kurt as in "Epiphany" CP-23 in NMB.  A light went on when you we're talking about making your own faired rudder.  I did the same, using a 12:1 foil shape still using it.  I called mine a rudder slipper" since it slipped over the factory flat blade.

Bob P

[roland cobine]

 three words-----buy the rudder