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PostPosted: Thu Jul 25, 2013 4:51 pm 
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Location: Florida Panhandle
Yesterday we went out on the new boat for the second time and noticed a fair amount of rudder or daggerboard hum. I was in the pocess of looking over the rudders today when I decided I was gonna try to swap in my pretty red EPO2 rudders from my H16. If the bolt pattern was different enough I could create a metal plug to fill the holes while the rudders were on the 20 in case I didn't like the outcome. I found out very quickly though the EPO2's are so much different in shape than the original 20 rudders that there was no way I would be comfortable match drilling the holes. So I installed the castings and started to bungie the rudders in place to try and get the right fit for drilling, when I noticed the H16 holes were pretty close. For grins I installed the bolts thinking I was gonna have to drill so close to the H16 holes this wasn't gonna work without the normal filling then redrilling. Amazingly, I was able to install the bolts and with an adjustment on the upper arm I got 1 3/16" on my measurements (12 inches down from the casting, a line through the center of the rudder pins down the the 12" line). I didn't have to remove any material from the casting or the blades.

My H16 has what I consider perfect helm balance, I've rebuilt the entire system from installing bushings in the 1 piece gudgeons to shimming the blades in the casting. Almost no slop and the boat will turn to weather nicely (within 50 yards ish) if we fall off. Every drill pattern I've seen shows a completely different pattern for the H16 and H20.

I'll find out tomorrow when I put it in the water but can anybody tell me if this is normal or should I be very afraid?

I'm happy if it turns out well but not so confident it will....

Cheers!

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2001 Hobie 16, "Spirit of 76 sails" #18515
1999 Hobie 20, Sail #1005
1981 Hobie 18, Dead!
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PostPosted: Thu Jul 25, 2013 5:06 pm 
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Likely the rake angle will be off if you used existing holes.

The EPO does work well on the 20 though.

Quote:
RUDDER RAKE -

Rudder rake (forward or aft in the lower casting) changes the helm feel. Weather helm (pull on the tiller) is caused by the rudder being aft of neutral. Lee helm is caused by the rudder rake being too far forward. Best adjustment is to have slight weather helm on all sailing angles. This allows you to hold the tiller against a slight pull for stable sailing angles. The boat should round up slowly if you drop the tiller. Lee helm is dangerous and can cause you to loose control of the boat. Neutral helm can be difficult as the tiller is pulling and or pushing against you on different sailing angles and can cause you to have erratic steering.

On older boats, rudder rake is adjusted by re-drilling the rudder blade. Either the upper casting hole or possibly both. Newer boats use the upper casting plate (see adjustment under "CAMS" above) and set screw in the lower casting for rake adjustments. There is a basic rudder rake setting to compare to. You can also use a drilling template http://www.hobiecat.com/support/tech/rudder.html

For proper rake adjustment you may need to try several settings. Helm feel will change with different mast rake, sailing angles and sail settings...

Start off with the rudders in the locked down position. Measure down the blade 12" from the bottom of the lower casting. Mark the rudder with a line 2" long perpendicular to the 12" point (fore and aft on the blade). Using a very thin piece of line, starting at the top of the rudder pin, align the "line" with the rudder pin top to bottom (on the pins center line / axis) and check where the line intersects the mark on the rudder. Mark the point where your rudder pin axis crosses the mark you made 12" down the blade. Measure in from the front of the rudder. A larger measurement means that the rudder is raked forward more. More forward rake is less weather helm. Optimally, you should have 1 5/8" to 1 3/4" for a measurement. To achieve the 1 3/4" number, you might have to re-drill the front hole on the rudder or file away at the front of the rudder where it hits the casting. To much forward rake can cause lee helm and THAT is WORSE and even dangerous. The boats sail better and are safer if the boat rounds up slowly when the tiller is released.

You can use the above technique to measure and re-drill a blade. Mount the blade on the lower casting. Make all of the above measurements and set (and hold) the rudder in the desired rudder rake position. Lock the upper casting onto the rudder and lower casting. Push the upper assembly up into the cam to seat it tightly (that holds the rudder in the raked position once the rudder system is fully set up). Align the tiller arm angle (vertical position) with the rudder assembly on the opposite side of the boat. You can mark the bolt hole position or drill right through using the casting as a drill guide. You must hold the upper arm in position while drilling this way. I angle the drill slightly forward rather than straight through. This forces the upper casting forward more as the drill reaches the opposite side of the casting after going through the rudder blade. If the hole is too far aft, the rudder will slip aft a bit when under sailing loads.

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PostPosted: Sun Aug 04, 2013 12:41 am 
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First sail after swapping out the rudders and I was surprised at how well they were adjusted. It was a little too neutral for my taste at first, a slight adjustment on the upper arm and the helm had just the right amount of weather. doesn't make sense but I won't argue with success.

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2001 Hobie 16, "Spirit of 76 sails" #18515
1999 Hobie 20, Sail #1005
1981 Hobie 18, Dead!
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PostPosted: Fri Jun 13, 2014 8:08 am 
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Location: Grand Rapids, MICHIGAN
Will a 16 rudder system (cross bar, arms and castings with rudders) fix and work on a 18? I have lots of 16 parts and someone building a 18 up from parts is asking.

Like entire system - from gudgeons on out? (and up) = )


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PostPosted: Fri Jun 13, 2014 10:18 am 
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You would have to move gudgeons and change out the uppers. Not sure they would allow the lower one to be low enough to support the loads properly.

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PostPosted: Fri Jun 13, 2014 3:19 pm 
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Location: Jersey Shore
Rojoyinc wrote:
Will a 16 rudder system (cross bar, arms and castings with rudders) fix and work on a 18?


I highly doubt it will work. Not sure if all the 18s are the same, but I noticed on my '85 when I switched over the rudder castings to the new system this year that the aluminum plates in the transom are quite small, in fact only a little bit larger than the actual gudgeon. If you have to relocate the gudgeons, it is highly likely that the screws will not hit the aluminum reinforcing plate. If they are not installed in the plate, they will likely pull out.

Plus, the H16 lower rudder casing is designed to sit partially above the deck flange and the aft section of the deck flange on the H18 is much wider than it is on the H16, so this will likely not work. You would be much better off finding a used old or new style H18 rudder system than trying to fit the H16 system on the 18.

sm


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PostPosted: Fri Jun 13, 2014 3:58 pm 
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I'm 90% sure I have a complete Hobie 18 older style setup. I'd let it all go for very cheap if your buddy can use it.

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Tim Grover

Memphis, TN

1978 H16 (sold)
1986 H16 (sold)
1980 H16 (sold)
1996 H20 Miracle (just right)
Bought another H16. Solid!!


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PostPosted: Sat Jun 14, 2014 2:29 pm 
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Location: Grand Rapids, MICHIGAN
I was hoping to sell him mine from a 16. but I'll give him your email.


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PostPosted: Sat Jun 14, 2014 7:28 pm 
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I cant see hobie 16 parts working on a Hobie 18 other than the rudders themselves but i'm a pay it forward kind of guy. If I sell parts to your friend i'll paypal ya 20% on good faith honor. Helps everyone!
Cheers!! :mrgreen:


Sold all my Hobie 16's.
On a side note, i have leftover H16 parts that might work on a 20. H20 quick connection tiller assembly and EPO Rudders. Also have a killer H16 PINK Mainsail that maybe someone could use....... You can see it many many miles away!

_________________
Tim Grover

Memphis, TN

1978 H16 (sold)
1986 H16 (sold)
1980 H16 (sold)
1996 H20 Miracle (just right)
Bought another H16. Solid!!


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