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PostPosted: Sun Jul 15, 2018 1:37 pm 
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Adjusted mast rake on a 70's something boat. Would like to have the ability to adjust rudder rake without making it permanent, not wanting to re-drill the holes in the rudder. I run a small fab shop, so the possibilities are endless as far as modifications go. Slotting the casting, making cam plates, spacers, etc. should be easy enough, as well as adding a set screw. Is there anything else that may prevent me from getting this to work? I plan on pulling them next week and taking a closer look.


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PostPosted: Mon Jul 16, 2018 7:21 am 
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I have a pair of old style rudder castings with no adjustments.

I ended up 3d printing some spacers to go at the bottom of the rudder casting (taped to the rudder itself). It helps remove slop (while obviously putting the rudders back a bit so balance with mast rake). Since I've fitted the spacers, I've had no problems with the rudder cams and can lock and unlock really easily. Might be worth a try and it's quick and reversable

Image

Image

If you look carefully at the rudder, the horizontal strip from the bottom of the rudder is Kapton tape holding on the spacers.

Image


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PostPosted: Wed Jul 18, 2018 12:55 pm 
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Joined: Thu May 24, 2007 5:28 pm
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Location: Bristol, IN
I'm going to need to rake the rudders forward, toward the front of the boat. I ordered a rudder stiffening kit, but that is a great idea to take up the side to side slop in the front edge using printed spacers like that. I will have to modify to prevent the spacers from preventing the rudders from stopping since I need my rudders to go more forward.... I just happen to have a 3d printer as well. Do you have the .stl file, or CAD file still?
Thanks,
-Mike

andylsun wrote:
I have a pair of old style rudder castings with no adjustments.

I ended up 3d printing some spacers to go at the bottom of the rudder casting (taped to the rudder itself). It helps remove slop (while obviously putting the rudders back a bit so balance with mast rake). Since I've fitted the spacers, I've had no problems with the rudder cams and can lock and unlock really easily. Might be worth a try and it's quick and reversable

Image

Image

If you look carefully at the rudder, the horizontal strip from the bottom of the rudder is Kapton tape holding on the spacers.

Image


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PostPosted: Wed Jul 18, 2018 7:00 pm 
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Here's the tinkercad for the rudder shim. It's *very* basic, but should be a good starting point.

Everytime I do something in tinkercad, I keep thinking I should sit down and fully learn fusion 360.

https://www.tinkercad.com/things/jWNamyriuxa-hobie-rudder-shim/editv2?sharecode=cWAVTNWnUIO9gEMR0N5MfQ2MYu2EDI37uWg0yPGpGGE=

I previously printed a rudder cam, just to see if I could and it kind of worked. Not great, but was fun to try.

Edit: What is it about your boat setup that means you need the rudders forward? Not enough weather helm when block-to-block on the main sheet boom?


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PostPosted: Thu Jul 19, 2018 5:27 am 
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Location: Bristol, IN
andylsun wrote:
Here's the tinkercad for the rudder shim. It's *very* basic, but should be a good starting point.

Everytime I do something in tinkercad, I keep thinking I should sit down and fully learn fusion 360.

https://www.tinkercad.com/things/jWNamyriuxa-hobie-rudder-shim/editv2?sharecode=cWAVTNWnUIO9gEMR0N5MfQ2MYu2EDI37uWg0yPGpGGE=

I previously printed a rudder cam, just to see if I could and it kind of worked. Not great, but was fun to try.

Edit: What is it about your boat setup that means you need the rudders forward? Not enough weather helm when block-to-block on the main sheet boom?


I think fusion 360 requires a subscription of around $300/year. I know someone who swears by a program called sketchup. You have to dig around the net, but there is an older version that is stand-alone and free that works. He doesn't use it for 3d printing, but I think there is a way to output to .stl. I am lucky enough that I learned AutoCAD from middle school, and have had jobs using it ever since, about 20+ years. I remote into my work computer and use it at home as well. I recently learned solidworks, which is nice, but for what I do, simple AutoCAD works great. Both programs though take a long time to learn.
Only thing about my printer is that it's a stereolithography printer using resin and a projector to cure the layers. I have yet to find a resin that is strong, but not brittle. Our library has a filament printer I can use though.

From everything I've read, the more forward the rudders, the less weather helm, less pull on the tiller arm. It's also apparent if your rudders are not locked into position, if they are kicked out a bit, you can really feel how hard the tiller is to pull. I've inherited the boat from my father who passed a few years ago. Looks like he replaced a broken side stay at some point. Problem is, now there is one newer, shorter side stay, and an original side stay on the opposite side, and original front stay, so I had to make an extension on the bridle since the original front stays were shorter, and currently waiting for the other new style side stay to come in. The block gap is huge as is, and current setup, with no mast rake has decent but manageable "tiller tug", but once I rake the mast back and get closer to block to block, I would assume the tiller tug will increase quite a bit.


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PostPosted: Thu Jul 19, 2018 12:10 pm 
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Location: Jersey Shore
Regarding the original question-

I believe it is possible to modify older castings to add rake adjustment. My recollection is that many years ago there was a retro-fit kit that allowed the existing pin to be removed and a cam plate similar to the current design to be installed. I don't really know any of the details though.

I also seem to recall a while back someone posting how they removed the existing pin and milled the hole in the upper casting out to a slot. Then make a pin that's female threaded on each end, put it in the casting, and put a screw through each side. This way the pin could be moved forward/aft and then tightened in position once the desired rake was achieved.

sm


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PostPosted: Fri Jul 20, 2018 6:41 am 
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Location: Bristol, IN
srm wrote:
Regarding the original question-

I believe it is possible to modify older castings to add rake adjustment. My recollection is that many years ago there was a retro-fit kit that allowed the existing pin to be removed and a cam plate similar to the current design to be installed. I don't really know any of the details though.

I also seem to recall a while back someone posting how they removed the existing pin and milled the hole in the upper casting out to a slot. Then make a pin that's female threaded on each end, put it in the casting, and put a screw through each side. This way the pin could be moved forward/aft and then tightened in position once the desired rake was achieved.

sm


I couldn't find a kit when searching the net. I figured I could make something since fabrication is what I do. My first thought was to do exactly as you described, simply by slotting the sides, and using some all thread rod all the way though and nut both ends. My fear was that if for some reason the adjustment needed to go up or down slightly, it wouldn't properly work with the cam,but the more I think of it, it would probably be okay. once the cam rotates beyond a certain point and now pushes down, then force remains constant from that point on, so the cam wouldn't need to go all the way down if the all thread was slightly off.


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PostPosted: Fri Jul 20, 2018 8:55 am 
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I've found the kit for non adjustable rudders in an old issue of Hobie Hotline.

http://www.w1dm.com/projects/hotline/09 ... OTLINE.pdf

Page 7 of the hotline, is the Norco Sail Easy Raker advert from what looks like the 80's.

Looks like a hole in the top of the upper rudder casting then a adjustable plate.

I knew I'd seen it before (I spent a few days reading old hobie hotline magazines when I first got my boat).

Attached image incase hotline PDF ever disappears.

Image


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PostPosted: Fri Jul 20, 2018 10:51 am 
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Joined: Thu May 24, 2007 5:28 pm
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Location: Bristol, IN
Aha! Yes, this is what I had planned. I figured there would be a void between the block and the casting on the older ones, and I was going to just use a spacer block and some shims to control the height. Not sure if this solution would be better than slotting the sides of the casting and using threaded rod. Any ideas which would be best? The two side slots and threaded rod would be easiest to fabricate for sure.

andylsun wrote:
I've found the kit for non adjustable rudders in an old issue of Hobie Hotline.

http://www.w1dm.com/projects/hotline/09 ... OTLINE.pdf

Page 7 of the hotline, is the Norco Sail Easy Raker advert from what looks like the 80's.

Looks like a hole in the top of the upper rudder casting then a adjustable plate.

I knew I'd seen it before (I spent a few days reading old hobie hotline magazines when I first got my boat).

Attached image incase hotline PDF ever disappears.

Image


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PostPosted: Fri Feb 26, 2021 5:39 pm 
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Joined: Sat Jun 13, 2020 12:14 pm
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Location: Mount Vernon, WA
I've got the same situation as you and am wondering what you ended up doing and how it's been working so far?


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PostPosted: Mon Mar 01, 2021 7:45 am 
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Location: Bristol, IN
I did modify them, they do work fine, just a tad janky. I purchased a newer boat with the adjustable ones from the factory the following year, so I only spent a summer using them, still have them though. It's been a while, so my memory is a bit foggy, but I can provide pictures if you want. Unlike OEM, which has the plate with the radius on the one end, with adjustment slot & bolt on top, I just made slots on the side of the castings, and used a bolt & lock nut instead of making a plate. It's the same diameter as the thickness of the oem plate. The bolt can be adjusted forward/backward in line with where the now removed pin would have been. I used a mill to make the slots, but they could probably easily be done with other tools. 2nd issue is the castings didn't allow the rudders to move far enough forward, so I had grind out the castings to allow the rudder movement. I took way too much material out, I probably only needed to take out 1/2 of what I actually did. This made the boat want head downwind pretty heavily. I drilled/tapped and installed set screws to adjust the rudder limit, and was able to balance everything pretty well. In extremely strong wind, I'd get a rudder pop up. This only happened a few times, even with the nylon screw/spring pretty tight. I could never get the one rudder to within spec. when setting the stiffness. I thought it was a misalignment with my bolt latch, but apparently it wasn't. I moved them (springs & nylon screw) to my new boat, because I thought they felt more stiff than the ones that came with it. After fiddling with them on the new boat for a while, I ordered new springs, and apparently, the old springs were just shot, new springs got everything to lock nicely into place to spec.

Kind of a side note,
On one of my new castings, I noticed a crack formed on the the top, down the center a couple inches. I drilled a relief hole at the end of the crack and welded it back up, but that got me thinking about the old castings that I modified. If the new ones can crack at random, there is a lot of "pinching" force on the ones I modified when you adjust and tighten up that bolt. If I were to use them again, I'd get a sleeve, make it just barely fit inside the casting, and use an undersized bolt. That way the clamping deflection would be held by the sleeve, and not drawing in the casting and overly stressing it.


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PostPosted: Mon Mar 01, 2021 10:35 am 
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Location: Jersey Shore
Quote:
2nd issue is the castings didn't allow the rudders to move far enough forward, so I had grind out the castings to allow the rudder movement.


The alternative to grinding the casting would be to notch the rudder blade to allow it to kick farther forward. This would probably be considerably easier than grinding the casting. The Hobie class rules even make an allowance for this.

10.6 Rudder blades may be notched on the upper leading edge up to a maximum of 1/2 in. (12.5 mm) to correct helm.

sm


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PostPosted: Mon Mar 01, 2021 11:48 am 
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Location: Bristol, IN
srm wrote:
Quote:
2nd issue is the castings didn't allow the rudders to move far enough forward, so I had grind out the castings to allow the rudder movement.


The alternative to grinding the casting would be to notch the rudder blade to allow it to kick farther forward. This would probably be considerably easier than grinding the casting. The Hobie class rules even make an allowance for this.

10.6 Rudder blades may be notched on the upper leading edge up to a maximum of 1/2 in. (12.5 mm) to correct helm.

sm


Even better, it took a while to grind out the castings.


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