I'm putting the rudders back on an N5.0 I've Been working on and have a question about the pivmatic system. I've looked around on here and am pretty sure everything is rigged right but the rudders won't stay up. I used brand new 1/4" shock/bungee cord stretched pretty tight through the tube. What's the trick to get them to stay up?
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Mac
Midlands South Carolina
AHPC Viper USA 366
A Cat USA 366
Super Cat 17
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Pivmatic question
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Posted: Jan 27, 2013 - 05:37 PM
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Posted: Jan 27, 2013 - 06:16 PM
The bungee inside the tube pulls the rudder up when needed. I used 3/8" dia bungee on my SolCat and it worked. I pre-streched that bungee during an instal. In addition I run another 1/4" line to the side of the tiller bar where I had another cleat that I used when I wanted keep rudders up when on the move. I think there is are pictures here in photo albums of entire set up.
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Adam Bartos
Nacra 5.0
SolCat 18 (sold)
Lake Zurich, IL
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Posted: Jan 27, 2013 - 06:36 PM
The shock cord should be doubled up, with the bitter ends at the top of the tiller arm.
I used 5/16" cord, and pull it tight, add a couple hog rings, pull tight, add a couple more rings, etc, until it has the tension desired, then trim to fit.
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Rob
OKC
Pile of Nacra parts..
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Posted: Jan 27, 2013 - 07:43 PM
Thanks. Ill try and double it tomorrow and see if that works, if that doesn't ill go up in cord size.
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Mac
Midlands South Carolina
AHPC Viper USA 366
A Cat USA 366
Super Cat 17
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Posted: Jan 27, 2013 - 09:01 PM
Note that the pre-1985 rudders are quite heavy and I've never gotten them to stay in the up position just from shock cord tension along. The main idea is that the shock cord provides enough tension so they pull up part way when you are in the water and the rudders are bouyant. This is really all you need most of the time so you can clear weeds and the like and they release properly when you hit something. The newer style rudders (you can tell the difference because the newer style have a right angle cut out in them, thanks Dan Berger for that info) appear to be foam core instead of wood, they seem to be about half the weight of the older ones and may stay up better because of that.
So even if you don't get them to pop up with authority as long as they do in the water you are fine. You will still have to tie them up when you trailor anyway.
D.
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Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
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Posted: Jan 27, 2013 - 09:17 PM
1/4" is too light, don't bother wasting your hog rings. The rudders on the 5.7 & 5.0 are long, & heavy, longer than the 5.2.
Buy good quality 3/8", or even 7/16". You need to run it as a loop,(double) through the hole in the rudder blade, then up the tiller bar. The easiest way is to first tie it in a loop, then run a line down the tiller bar, around the bungee, using the line to pull the bungee through the tiller bar. It's easier to have a helper (and the rudders mounted on the boat)pull the line, thereby stretching the bungee. You can then insert the X bolt & hog ring it where you need it.
If you don't have hog ring pliers, do some experimenting by just tying it to find out how long of piece you need. Then (record that length for future use) tie the bungee with a knot that will pass up the tiller tube. Run a line down the tube & pull the bungee through. You will need to stretch it pretty good, & hold it there till you insert the X-bolt.
I strongly suggest placing a 6" or so piece of tubing,(or the stuff you buy to protect line from chafe) over top the bungee, where it goes through the rudder blade & back into the tiller tube. Without it, your bungee chafes on the edge of the tiller tube & wears quickly. Another option might be to chamfer the end of the tiller tube smooth.
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Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
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Posted: Jan 28, 2013 - 07:54 AM
Having been a Hobie guy for 20 years I HATED the pivmatic system. I did all the dos and don'ts and they still sucked out loud. Total POS in my opinion. I am sure others like them and hate the Hobie cams but I am a Hobie Cam guy and will alway be that way. 20 year and no issues.
Back to the Pivmatic; I searched and found parts for the inter rudder system, it works great. I used a set of rudders, castings and arms bought piece meal on this forum. I think I spent under $500 on the whole set up. Drilled the boat for them to fit. Used the 5.5 cross bar and pretty much done. They go up they go down they stay down an stay up. Easy to adjust the rake and overall very happy with the set up.
This is only my opinion but if you can fid the inter style it is worth never having to fight the pivmatic: ropes up ropes down, bungee here bungee there, what do I do with all these ropes when I am sailing anyway BS. HTH, Richard.
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Lake Perry KS
H-18
N-5.5 UNI +spin
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Posted: Jan 28, 2013 - 08:04 AM
I'm about to put the boat up for sale so I'm not planning on putting anymore money into it
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Mac
Midlands South Carolina
AHPC Viper USA 366
A Cat USA 366
Super Cat 17
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