Hobie 18 rudder issue

Are you sure that it is the proper plunger? The Hobie 18 plunger is different from the Hobie 16 plunger. The H-18 is a different shape, more oblong than the H-16 which is round. The reason I ask is that I have found a few 18 castings with H16 plungers installed. How much tension are you putting on the spring with the tension screw?
I have been in Hobies for 20 years and have never seen one break. This summer I have now seen three of these (yours are 4 and up) fail in a very short time.
I think in the past they were made solid and US made now they are hollow and offshore (like everything else). We lube them up every time we go out, that seems to help quite a bit. Tension is a zen thing, I set it on with the boat on the beach wheels where a tug on the bottom unlocks them. If they are popping up all the time there may be several reasons, one is tension is not enough, the other is cam is worn, the best thing to do is set them on the trailer, tension, toe, rake are all critical for them to work correctly.
I would buy new cams with the rebuildable screw set up and new plungers and call Hobie and see what they say. HTH, Richard.

any pics of these plungers? it sounds like it could be a material spec issue...
do you have, can you borrow an old plunger to compare the sizes by micrometer, try and measure flex etc.
i don't know the hobie cam system much at all but if they are getting meshed up in there could they be too soft, could your marine grease be attaching the surface, softening them?
if it's just a plunger could you make your own out of some solid plastic stock?
another big read from a hobie site
http://www.hobiecat.com/forums/viewtopic.php?t=467
Edited by erice on Jul 18, 2012 - 05:24 AM.
1982 nacra 5.2
2009 weta


I've never had this type issue with the plungers. From what I understand, the problem is caused by defective castings, not the plungers themselves.
To lube the plungers and cams you can use any type waterproof grease. I use white lithium grease because I keep it in my toolbox to use on the trailer ball.
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Damon Linkous
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