Rudder adjustment

I have a hobie 18SX 2003 version, was out yesterday in a 16 Knot wind, one of the rudders kept lifting. I tried to make some adjustment's but every turn I was trying to lock it back in. Do I need new cams? When the rudder is locked down should there be any up and down movement?


Marty in Saskatchewan

You should review the rudder FAQ.

It sounds like you probably just need to tighten the screw that sets the cam pressure (large plastic screw on the underside of the lower rudder casting). If the cams are otherwise functioning properly (cam not getting stuck in the down position) then that should be all you need to do.

If the rudders are kicking up without flipping the cam up, then you would need to adjust the slider plate in top casting and/or replace the cam.

When the rudder is locked down, there should be no relative motion between the upper and lower casting (however the whole rudder system may wobble up and down slightly if there is slop in your rudder pins).

sm

I will replace the rudder pins, and look for that screw at the bottom of the cams.

Replacing the rudder pins will have no effect on how the rudders kick up. You may want to replace the bushings for the rudder pins to reduce slop, but this still has no bearing on how the rudders kick up.

The screw on the lower casting is what sets the cam pressure.

sm

OK thank you
I will adjust tonight and see if I can make the changes

You should have the "new upgraded rudder system on that boat ...so a couple of questions ...

1) Looking at the "lowwer" rudder casting .... how is the black plastic rudder cam held in place??? ... is there a "rivet" holding it in place??? or a "slotted" (on both sides) screw holding it in ??? (that "slotted" screw" is known as a "amorphic" stud, the two sides screw into each other ...) You can not tell until you remove the cam ... but the center hole in the stud/post can become oval or the stud/post can become tilted/cocked and then the cam no longer works properly.

If it's a rivet .... then you have "origonal" cams ... and they may need to be replaced. There is a "kit" to replace the "rivet" w/ a "amorphic" stud and install a new cam. Those "cams" do not last forever. To remove the rivet ... you can drill the rivet out ... or ... you can using a "hacksaw" blade between the cam and casting cutting vertically ... cut the rivet out ...(you may scratch up the casting alittle but some black paint fixes that). The second method is a little safer for the casting .... as I've seen some people ruin their lowwer castings when the drill bit "walks". If you do use the drill bit method ... start w/ a small bit and work to a larger size .....

If it is already a "amorphic" stud ... then it is easy to unscrew and replace the rudder cam.

2) You may wish to unbolt the rudder blades from the upper and lowwer castings and check those mounting holes through the blades ... they have a tendency to become "oval" over time .... and it doesn't take much to make it so that the rudders don't lock-down properly.

The best way I've found for unlocking a stubborn rudder cam is a "putty knife" placed between the casting and the cam vertically ... and you press down on the plunger that comes up through the casting and acts a a "detent" to lock the cam in place ... press down and rotate the cam by hand. Works nice .... I carry a "putty knife" on the boat in my "emergency kit".

If you need new cams .... you may wish to fill the "hollow" side .... I found "Marine-Tex" works best .... and it makes the cam laaaassst alot longer.

Please check these points out ... it maybe a combination of all of the above ... a little "slop" here ... alittle "slop" there and all of a sudden the rudder system doesn't work well anymore ....

_________________
HarryMurphey
H-18 mag/ #9458
Fleet 54 Div 11

I examined the cams once again tonight and found the one causing me trouble was almost missing the adjustment screw. I could hand tighten it, It is not as tight as the other, but with my handy screwdriver on the weekend I will snug it up and see if that makes a difference. The cams are the originals, they are pop riveted in, if I still have troubles after these next adjustments, I will try and limp into the off season where I will then change the cams.

Supposed to be real windy here this week.

Marty

I was out today in a 15 knot wind with gusty conditions and that rudder stayed glued down, It made the day extra amazing. I just had to concentrate on keeping the hulls above water. A remarkable amount of speed with a few close calls, turning upwind saved my bacon.

Thanks
Marty
Hobie 18SX