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Shoal draft rudder
Posted: Sun Apr 13, 2008 10:50 pm
by Guillaume C.
Amayotte asked me for dimensions of my C26 rudder, I'm posting them here so they are available if anyone else need them in future. This model have the save draft as the swing keel raised, does anyone know if it made by Crysler or a custom part?
It is made of foam with one layer of biaxial cloth (9 oz maybe... not sure). If I was to make a new one I would probably use a NACA profile to increase the performance, but it's working allright as-is. I do not know the internal structure. Let me know if you dont understand the measures, this is not the best technical drawing Ive done!

Posted: Mon Apr 14, 2008 9:18 am
by Banshi
Heavin's to betsy that's quite the beast you have there, if it won't turn the boat then ain't nothin gonna turn it

It's got to be a home brew, all the ones i've seen so far are swing. Clearly the length is a trade off to shorten it up and the position on the shaft helps to keep it from being to heavy handed when turning. I bet with a Spinnaker up (maybe even without in heavy air) on a Broad Reach or run it would still build up your arm muscles?
Posted: Mon Apr 14, 2008 10:55 am
by amayotte
That's awesome,
Thanks Guillaume.
I will start working on it.
Adam
Posted: Fri Apr 18, 2008 5:16 am
by Guillaume C.
Banshi wrote:I bet with a Spinnaker up (maybe even without in heavy air) on a Broad Reach or run it would still build up your arm muscles?
Did not had the occasion to try a spinnaker so cant answer, but with main&genoa it has never been heavy. I'm not soooo sure it's home-made as I vaguely remember to have seen picture of another boat with this rudder..:/
Posted: Fri Apr 18, 2008 5:32 am
by EmergencyExit
You've probably seen that pic on the swing keel backet repair page on Windwards site.
http://chryslersailing.lizards.net/sail ... acket.html
Posted: Fri Apr 18, 2008 5:38 am
by Guillaume C.
Bingo! They are similar but not the same, 2 different home-made I guest
Posted: Fri Apr 18, 2008 7:01 am
by Banshi
Different year perhaps, sure does seem larger than needed though, but these aren't America's cup boats either, where drag means defeat

Speaking of keel brackets...
Posted: Fri Apr 18, 2008 1:06 pm
by Windward
If anyone has occasion to remove the keel shoe brackets, please please please take good pics, and I'll post them on chryslersailing.lizards.net. You might consider making a plaster cast of them, too, which would simplify making new ones. I'm particularly interested in what the keel / shoe mating surface is like, since in the drawings it appears the keel itself is concave there.
I want to replace them on Windward... don't trust them or the keel pin that well after all these years, but would like to have some new ones fabbed up prior to getting into it. Were I to replace them I'd like to use something like lead and epoxy to fill and fair the exterior, adding a few more pounds of ballast in the process. I'll bet another 20 - 50 # down there would make a difference when life gets puffy.
Off to the boat for the weekend. Fair Winds, all.
Posted: Fri Apr 18, 2008 5:37 pm
by EricBerg
Jeff, if anyone bites with the keel bracket info, I'm in for a set also. I hope to chip off all the rust, fairing material etc to see what it looks like this spring. I'm not real confident of what I will find. I bet there are quite a few of us who'd like a set to go. Drive the cost down considerably.
Eric
79 C-26
SiouxFalls SD
"a curious thing"
Posted: Fri Sep 12, 2008 12:00 pm
by Guillaume C.
Update: I've been able to test the boat more recently and have found some limitation with this rudder. When the boat is heeled so that the rail touch the water, the rudder is partly in the air and with this limited surface the boat turn to the wind
So...not the best model if you want to race, but if you are often in shallow depth, this is still a good option, the boat steer fine in more normal condition
Posted: Fri Sep 12, 2008 12:14 pm
by Banshi
Yeah but if the rail is in the water then you should probably be reefed anyways.
Posted: Fri Sep 12, 2008 12:23 pm
by NoRush
Can't keep the rail out of the water in anything more than 10 kts

Posted: Fri Sep 12, 2008 12:52 pm
by Guillaume C.
How were you heeled in your best upwind performance? When I had enough wind to test, I seemed to gain a bit of speed when the rail go to water level, but could not stay this way long enough (rudder and lack of wind) to test the limit to get optimum speed
Posted: Thu Sep 18, 2008 9:36 am
by Holiday
Is your shoal draft rudder as deep as the keel when the keel is up? If not can you estimate how much shorter the rudder might be? I have been thinking about a rudder the same depth as the raised keel. This would be build with a weaker bottom section to prevent hull damage by the rudder shaft if grounded hard.
Posted: Thu Sep 18, 2008 1:58 pm
by Guillaume C.
yup same deph as the raised keel
When I'm in shallow deph i let the keel down a bit, so if I ground I can raise it and back up.
Posted: Tue Aug 11, 2009 7:38 pm
by amayotte
Guillaume,
I know it's been a while but I am now gathering all the parts needed to make a shoal rudder. I have some questions though.
Would you say that your rudder would work better if it was longer or shorter?
Is your rudder removable from the rudder post?
If it is removable how does it attach?
do you find that there is a lot of resistance or pull when steering, or would you say it is fairly balanced?
This is what I am thinking of doing for mine:
I was going to make it the same draft as yours : ~26"
I was toying with the idea of making it 36" long. Seems kinda long...not too sure.
I am either going to do a NACA0013 or NACA0015 ( with a 5% leading edge radius)
and I was going to make the rudder removable in case it doesn't work.
Tell me what you think,
Adam
shoal rudder
Posted: Wed Aug 12, 2009 5:51 am
by mainsheetmike
My boat has an identical rudder. It is split on the trailing edge from water intrusion into what lookes like plywood. I am taking it off and filling the split with epoxy, then glass cloth around the whole rudder. I too was worried how the boat would respond with the rail down in heavy seas. The preivious owner took the boat to the Bahamas three times, and didn't have any problems. I wounder if threre was a pattern or plans for these rudders at one time, as they look the same. mike