Rudder Rebuild, Spinnaker Thoughts

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Missleedee
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Joined:Sun Aug 07, 2011 3:20 am
Rudder Rebuild, Spinnaker Thoughts

Post by Missleedee » Sun Aug 07, 2011 4:19 am

Hi All,

We have the kick up rudder and are in the process of rebuilding it. It has the wood core and is the minimum length according to the rules. For racing does this minimum length work best (less wetted area) or do factors such as steerage play a bigger factor (wind force dependent I'm sure) and favor the extra 3 inches? We only want to rebuild this rudder one time and could add length now. We also found the cores leading edge not symmetrical and may have to reduce the thickness to near the minimum tolerance to get it right. Has there been any structural problems (breakage) with the minimum allowable thickness?

We are going to fly the spinnaker on Monday and had a few questions. Does this class use twing lines on the guy instead of the pole downhaul, in most conditions, like a lot of the other boats in this size range? If so where are you mounting the twing turning block? Are you storing the spinnaker pole on the boom or the foredeck? Where are you launching the spinnaker from, forward hatch or companion way?

There are more questions to come when a search of this and the other sites don't answer our questions.

Thanks a lot for helping us get up to speed.

Lee & Rick

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cklamp
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Re: Rudder Rebuild, Spinnaker Thoughts

Post by cklamp » Mon Aug 08, 2011 7:17 pm

Lee, Rick, welcome!

I can't comment on the lengthy, but for the Rudder Width, you probably want to be as close to the maximum as you can get, rather than the minimum. It should get your foil shape better, and provide more lift.

For the spinn questions, I don't think i've seen anyone using a twing line, but you're best off checking the Class book, or hopefully someone smarter than I will post. Some people (me and many others) store on the boom, Some store it in an upright postion at the front of the mast, and I know another boat in Fleet 1 that leaves it attached to the mast, and just let's it sit down on the foredeck... So, do what works for you:) Spinnaker launching, most in Fleet 1 launch from the companionway. I haven't seen it, so can't comment, but I've head that Mean, Green Ugly in the fresno fleet has a launcher in the foredeck/hatch or something? Maybe you can inquire or someone else can comment on that since I have no first hand knowledge... just myth's and legend's to go on:)

later
Christian
Fleet 1 Webmaster
http://www.sj21fleet1.org
http://www.sj21fleet1forums.org
SJ21 1974 MKI #897, Mizu

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Capt. Woogy
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Re: Rudder Rebuild, Spinnaker Thoughts

Post by Capt. Woogy » Mon Aug 08, 2011 8:04 pm

Welcome as well. I'm sure you'll soon find out why we love these boats, once you start racing them. I don't have a lot of time to go into it now but I'll give you the short version of how I have Wooglin set up.
- Guy hooks on the rail just far enough to reach them from the cockpit. I still use a down-haul as well.
- Pole on the mast. PVC coupling attached mid-boom. We just leave the topping-lift and down-haul attached.
- Launch from a basket in the the companionway hatch. The only drawback is getting it around the spreaders. (We try to pull the guy to the bow before hoisting)
Good luck on your first race.
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Chris Popich
"Wooglin Juance Again" MK1 #986
Fleet 1 - Seattle

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cklamp
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Re: Rudder Rebuild, Spinnaker Thoughts

Post by cklamp » Mon Aug 08, 2011 10:10 pm

Chris actually stores his pole on the boom, I think mast was a typo:) I run the same setup as he does on the boom. I've also, and I think Chris has as well, setup both sides of the boom for pole Storage. This is nice to have when doing some point 2 point racing as you can store on whichever side is easiest.

As he stated a PVC Coupling is mounted mid boom. I think I used a 3" diameter one, but your pole will dictate what size you use. I also mounted some "air conditioner foam" inside the coupling to minimize some of the banging and clanging noise. Chris has used some of the Forespar plastic pad eyes at the forward portion of the boom to clip a pole end into. I tried using the same, but at one race myself and crew kept having issues hitting that pad eye easily, so I found some stainless Pad Eyes with a larger loop and riveted them on.

Later
C
Fleet 1 Webmaster
http://www.sj21fleet1.org
http://www.sj21fleet1forums.org
SJ21 1974 MKI #897, Mizu

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Diarmuid
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Location:Laramie, WY

Re: Rudder Rebuild, Spinnaker Thoughts

Post by Diarmuid » Tue Aug 09, 2011 3:29 pm

Black plastic MagLite clips fit our Forespar (1.5"?) spi pole perfectly & are very beefy. We have one up the mast & just swing the pole vertical on its ring & clip it securely. Would work on a boom, too.

http://www.amazon.com/MAGLITE-ASXD026-F ... B00002N9ER

Are you planning to glass over the wood rudder core once it is reshaped? I'd trust a glassed blade of class-minimum thickness, but not a varnished wood one (unless laminated -- that's a different animal). I recommend making a NACA 0006 or 0012 template for your intended chord(s) and using that to achieve symmetry and maximum lift/drag performance. I shaped our rudder out of UHMW polyethylene (which is not class legal) using the NACA foil numbers, and we are very happy with the result. It's also a good chance to slenderize other parts of the assembly to save weight on the transom. Our stock kick-up design was 30+ pounds, even with a mahogany blade! The rebuild shaved almost 15 lbs, without compromising strength. Old rudder head:

Image

New rudder:

Image

Foil shape:

Image

Given our boat speeds, a fatter foil would be okay -- tho this one has no trouble turning the boat at low speeds. Max thickness is 1.25".

Mark Sailmaker
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Re: Rudder Rebuild, Spinnaker Thoughts

Post by Mark Sailmaker » Tue Aug 09, 2011 5:22 pm

Here in Eastern NC, most boats use twings led from just forward of the shrouds to a cleat on the cabin top. We use small plastic Holt/Allen snatch blocks on the twings so you can take the one off the sheet in drifting conditions. Having twings allows you to move the lead forward when running in big breeze to stabilize the kite. Also very useful on the jib sheet for a reaching lead. We have a pole downhaul as well - that is led from the base of the mast so you don't have to adjust it when easing or trimming the pole. For the last couple years, we've been leaving the pole on the mast ring, setting the forward end on deck and tacking over it. That's ok with the jib, but a pain with the genoa. I'm going to work on boom storage over the winter. Each method has it's benefits and costs. I worked out a shock cord topping lift retractor that allows the pole to be hoisted and struck without going on deck - a big asset for doublehanded sailing. Most boats hoist and retrieve the kite from the companionway with a bag like the J-22/24 use. Trapping the kite with the main can be a problem if you ease the main too far at the top mark. The Family Dommel launches and douses from the forward hatch, but they almost always sail 3 handed with the kite, so somebody can go forward either on deck or below for the douse.
Re the rudder - we have a minimum length rudder and I think it's faster - less drag. We've never had a control problem - just don't try to over power the sails with the rudder...it doesn't work. The main is many times bigger and will always win. Make sure that after you fix the blade, you relieve the sharp edge on the inside lower edge of the rudder head - file or sand a big radius on that edge. I've seen several broken blades because of scoring on that edge.

Missleedee
Posts:6
Joined:Sun Aug 07, 2011 3:20 am

Re: Rudder Rebuild, Spinnaker Thoughts

Post by Missleedee » Fri Aug 12, 2011 1:36 am

Thanks folks. This answers a lot of questions and also brings up more. We just picked up the boat yesterday and are getting registration and such taken care of. Hopefully we will get her in the water on Mon or Tue. We will probably build a rudder for racing down the road. The spinnaker ideas are great. I figure we have most of the winter to sail the boat (Lake Havasu AZ) to get everything up to speed (including the crew). We are trying to determine where to go next spring/summer and it's looking like the Northwest. Sorry East coast guys but our RV does not have a clock that works on Central or Eastern time. As we get things rigged look for a stream of questions. We really appreciate your effort in answering and hope to meet many of you. Lake Havasu AZ Western Mid Winters anyone?

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