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Matt Ralls |
New rudder for wing keel boats |
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Larry Howard posted previously about finding a group of wing keel owners who might want to replace their barn door rudders with a more balanced version. He
has been busy lately and hasn't been able to follow up. I am definitely going to replace the rudder on my '89 boat and wondered if their are others
who would like to do the same. The larger the group, the lower the design and set up cost per rudder. Any of you seriously considering an upgrade?
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jerrygagerman |
#1 | |||
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I'm interested.
Jerry Gagerman Mk I C-42 #431 Current Sea |
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melelana |
#2 | |||
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Guys,
Apologize for being out of touch for a while. Work has kept me out of touch and too often off the water lately. Writing this from Cape Town... Looks like it's not as big an issue as it was a couple of years ago. I would think it will take at least 15-20 committed owners to pay for a design ($500-1000), non recurring tooling (about $5,000) and low production rate recurring costs or $2,200 or so each. It would be so nice if Catalina would do for the shoal keel boats what they did for the fin keel boats years ago - introduce a redesigned rudder that's more efficient and has more balance area. Not a trivial task because additional balance area has to compete with control under power and the draft restrictions are real and impact shape a lot, but there are better options than the current barn door. I'm still willing to pitch in as I can, but it will take more than the three of us to make it happen.
Larry
Melelana Catalina 42 #175 1990 3cbn, wk Solomons, MD |
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fthomasjones |
#3 | |||
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capns: I am also interested in a group effort on the rudder. let us know what we can do.
tom jones Silver Fox Annapolis/Tortola |
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Doug Boyd |
#4 | |||
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Count us in too--we're encouraged by the building momentum.
Cheers- Doug |
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snsusi |
#5 | |||
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We're in too. Let me know when you get a quorum.
Patrick Duffy Athena - C42 MK1 #63
Last Edited By: snsusi 11/04/07 20:13:01.
Edited 1 time.
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svzephyr44 |
#6 | |||
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Perhaps this is a dumb question - but if we invest in all this does Catalina then get the rights to put the new improved design on all their new 42's? It
would seem to me that about $6,000 of the cost should be borne by Catalina as a product improvement. I would consider fitting the new rudder, but not funding
Catalina's R&D.
Roger
REBOOT USA 60493 |
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melelana |
#7 | |||
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That's the crux of the problem. Catalina feels the existing rudder is adequate and a new design is not needed. I approached Gerry Douglas with the
question at a rendevouz about 3 years ago. To be fair, there are some limits as to what's possible with the shoal draft (rudder draft needs to be at a
minimum 4" less than the keel) and balance area. Increased balance area would reduce weather helm pressures (but the weather helm would still be there)
but exacerbate the "hard left turn" tendancy the boats demonstrate under power as prop wash would have more balance area to leverage.
In talking with a noted designer, he's prepared to draw up a new rudder for about $500.00 and work with a rudder manufacturer to see if an existing mold could be adapted as a "close match" to save the mold costs. In talking to a rudder manufacturer, then recurring costs would be about the same or a bit higher (10-20%) than Catalina's. Those who paid the non recurring woud own the rights and we would have to discuss with the designer if we "owned" unrestricted rights or if a license fee would be needed for each rudder. The Cal 40 fleet did this a few years ago and engaged Carl Schumacher (before he died) to design their new rudder. With 20 owners chipping in, it cost about $1800/rudder, including new HMWP bearings that one of the owner's designed and prototyped. In their case, they deeded the design rights to the guy who worked up the bearings, but I believe it's now available to members of the Cal 40 association without charge. Best case would be if Gerry had a change of heart and incorporated a new design for us "stubby keel" boats as he did for the fins when he incorporated that nice elliptical rudder at around hull 500. However, the existing rudder works, emgineering costs both money and time as has to compete with other demands and margins in the boat business are challenging. Long way to answer the question, but anything we fund the NRE on belongs to us, not to Catalina Yachts. I'd love to put a new rudder in Melelana before the spring season gets started.
Larry
Melelana Catalina 42 #175 1990 3cbn, wk Solomons, MD |
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svzephyr44 |
#8 | |||
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Larry:
Thank you for taking the time to explain. I was not trying to be a pain, just trying to understand. Further: What would I expect from a new rudder? We normally trim out weather helm to 2 - 4 degrees in all wind conditions. In general, the stronger the wind the more weather helm we leave in. Should I expect to go faster? I feel very ignorant, but I don't know what benefit to expect. Does the concept of a "balanced rudder" suggest that the pivot point would be more in the center of the rudder than the end? Given the configuration of the drive shaft and the rudder does this suggest some major structural work? I think on Reboot (#493) that when my prop is feathered there is only an inch or two between the back of the prop and the rudder. Does anyone design rudders with trim tabs? In the aviation world the solution to the barn door seems to be adding a trim tab to offset the effort. That is also, I understand perhaps incorrectly, how many of the wind activated steering systems get the mechanical advantage needed. Would a trim tab design permit reducing steering effort while crusing but still provide a smooth rudder surface while racing? I say that as I presume a trim tab would introduce additional drag that would be detremental to speed in light winds. Again, I am not trying to be a pain, but just trying to understand. Roger Reboot #493 |
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melelana |
#9 | |||
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Roger,
No problem. I'm feeling guilty that work committments have kept me from communicating as much as I'd like. Trim tabs. Trim tabs were very popular in the 60's and early 70's (and were widely used on 12 Meter boats) to balance helm forces and are still used on some boats today. In the early 70's, I was the helmsman on a 54 footer with a trim tab and it was pretty unwieldy to use. After a season of sailing with it, we glassed it in and went without as the IOR rating rule penalized us for the tab and it didn't add much to performance. Linkage is complicated (and expensive). Most complaints about the existing rudder center around the way in which it loads up in 15-20 knots as the boat heels. In adition, as weather helm builds up, the additional rudder angle needed to counter it adds significant drag, slowing the boat. A more efficient shape (within the limits of draft) and fine tuning the balance area has the potential to reduce rudder forces and improve performance. A couple of owners have modified their rudders and report that they are happy with it. Old timers on the forum may remember "Gaston" who modified his rudder. The current owner's comments to me are : "Not having owned the boat prior the the new rudder I have nothing to compare it with but from what I have read there was a lot of helm with the original. I find the boat sails to wind with just a slight bit of weather helm in winds over 15knts and in winds under 15Knts the boat will steer itself without the wheel brake applied. I've owned a lot of boats and sailed a lot more and I find my boat steers as well or better than most . Motoring is another story ...you have to hang on with both hands. I assume this is caused by the proximity of the prop to the rudder (it's very close and was made closer by the install of 1" shaft saver/spacer). I also have an auto prop which may add to the problem. I really doesn't bother me as i use the pilot when motoring but I was wondering......" On Melelana, I have an Autoprop with the original rudder and I wouldn't say I have to hang on with 2 hands, but it does require constant right rudder pressure under power. Having raced a lot on "modern"fin keel race boats, there is a world of difference in feel and response. I'm sure that a big part of that difference is the short wing keel vs a 7+ foot, narrow chord fin on the race boat and I suspect any improvement we would see would be incremental, not revolutionary. As Bob Perry says, there's nothing that makes a boat go well to windward like deep draft and we have traded that off for thin water access. I would consider any design that was not a "drop in" replacement in the same way a replacement Catalina rudder unacceptable. One possible outcome is an opinion from the designer that only marginal improvements to the existing design are possible given draft and installation lmiitations and that might lead to a decision that a redesign just isn't worth the cost. Larry
Larry
Melelana Catalina 42 #175 1990 3cbn, wk Solomons, MD |
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nickwigen |
#10 | |||
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A few years ago Mrc Bisnare of Vive la Vie Hull #349. modified his existing rudder by adding some area and improving the balance. He had posted
photos of the modifications on the old forum site but I can't find anything now. Does anyone else remember any of this? (or am I making this all up?)
Nick Wigen
Ursa Minor #178 FK, 3-Cabin Portland, Oregon |
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