New Rudder System - H18

Could anyone tell me what is the parts I should buy to change the old rudder system on a 1982 Hobie 18.

Anyone has modified its pre-86 Hobie so that rudders release when they hit the bottom?

Yes, it's been discussed a lot on this forum. Check the thread "Rudder replacement?" There are other threads as well.

viewtopic.php?f=13&t=16807&hilit=+rudder

The old castings will work if properly maintained and adjusted. I've been using them for 25 years on my original '85 boat. Had it out two weekends ago in the surf, no issues.

To change out the rudder system, you will need two new upper rudder castings and two new lower rudder castings. You will also need to fill the existing holes in the rudders and re-drill for the new castings. Last you will need to relocate, drill, and tap the lower gudgeon mounting holes. Depending on the gudgeons you have, you may need to replace those as well.

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Yeah, I've read all those posts and still have yet to see anyone with an old rudder system that kicks up from the rudder hitting something or by pulling on the bottom of the rudder blade. I did the filing of the divot and greasing parts, and loose screw tensioning (along with all new parts) and still cannot make it come up by pulling on the rudder. It certainly is easier to unlatch it from the arm when you're sailing. I even messed with filing the "hammer" or latch so that it was easier to pull out (less hook). That made it super easy to unlatch via the arm (maybe too easy), but still no release from strike. BTW, I love this system even compared to the newer system since I'm careful not to hit anything. Compare it to the strings/latch combo nightmare on a Prindle and its saweet.

If someone HAS made it pop up from a rudder pull or strike, let me know!

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H18, H17 & Various motor boats

Mine will kick up (although I usually do raise them from the arm anyway). Don't know what else to tell you, other than back off on the spring pressure some more. Mine have almost no spring pressure (to the point that one of the spring screws is backed off so far I have it secured with tape to keep it from spinning out).

Just an experiment, but I would start with the spring completely removed. If it still won't kick, then look for where it is hanging up.

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I was not able to pull either of my rudders up by hand. I pulled hard from the bottom of the rudder. So I followed the threads in here and filed the latch flat so that there was no indentation to hold the cross pin in place. I greased it as well but would release without the grease. I sailed on the SC coast for a week without issue and they would come up when hitting the sand. Some after I raised the arm and sometimes not raising the arm. It was a beautuful thing.

divimon2000- if you have filed the "catch" absoulutelty flat, it may be that the holes in your rudders are worn larger and the slop is changing the angle on the release. Just a guess.

The divots on my boat were about 1/32" of inch deep and I had to file the upper area back until there was no divot at all. Even the smallest indentation would not allow them to release.

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1984 Hobie 18

anyone tried to completely remove the spring and tension screw?

Using a bungee cord from lower gudgeon, going around the tiller arm than back to lower gudgeon. This would keep the rudder down, until it hits something, bundgee would not keep rudder down on impact.

Looking at a Hobie diagram, for post 87 boat, Hobie added the plunger (did not exist before). What is it's use?

Anyone tried this modification? http://static.hobiecat.com/web_uploads/ ... 330100.pdf

Not sure whether completely removing the spring and screw and replacing with a bungee would work - it would certainly be easy enough to try though. I think the upper casting needs to engage the latch/ hook in order to stay seated. Otherwise the upper rudder casting may start to walk forward allowing the rudder to begin kicking up. This is just a guess though.

The plunger is specific to the plastic cam rudder systems and not required on the old 18 system with the latch/hook. The systems work on similar but different principles. On the cam systems, the convex shape at the top of the plunger engages a concave recess in the cam and this is what keeps the cam from rotating until impact. With the latch system, the pivoting latch simply locks onto the roll pin in the upper casting. The spring presses against a flat on the bottom of the latch. When the rudder is impacted, the roll pin forces the latch open and disengages - in theory at least. Unfortunately, excessive spring pressure on the latch will not allow the roll pin to force the latch open. The new system can have the same problem however since the cam is plastic the hook on the cam will just deflect and the upper casting will pop free allowing the rudder to kick. In this case, you end up with a cam stuck in the wrong position rather than a busted lower casting or transom.

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Thank SRM I didn't try this,

Sailinagin, good point! I'll check that as well.

Good to know they do pop up when set up properly. I'm on it.

No way would I go with the bungee.

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H18, H17 & Various motor boats

divi - keep us posted on your progress. Close up pics would help too if you still have issues.

Good Luck.

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1984 Hobie 18

Hi,

My experience w/ the "old" H18 rudder system is that they will not release .... and in fact the lowwer casting has a tendency to break .... it breaks were the upper rivet is on the narrow part of the casting .... I broke two of them ... with-in weeks of each other .... had to replace the lowwer casting both times ..... $$$$$'s

If you can make them work .... congragulations as that old system defeated me ....

"New" rudder system:
To install you need to flip over/move-up the lowwer goudgeon .... this reduces the spacing between the goudgeons. Remove the lowwer goudgeon .... align the bottom holes of the goudgeon w/ the existing top holes of the lowwer goudgeon in the transom ...install the bottom screws in the goudgeon .... drill and tap (2) new "top" screws for the lowwer goudgeon. The "aluminum backing plate" is usually large enough and located properly to allow for this .... but ???. Now if the goudgeon screws will not come out you will need to grind them off to remove the goudgeon ... (Dremel Tool!!!) .... its a SS screw into an aluminum backing plate ... and in time (w/ galvantic action and saltwater corrosion) has a tendency to corrode the (2) dissimiliar metals together. Hence the advise in the other thread to install portholes to gain access so you can replace the backing plates. I've known people to "thru-bolt the goudgeon w/ SS bolts/nuts vs tapping/screws ... but you still need access to the inside to tighten the bolts/nuts ....

Don't forget to "fill" the (2) old goudgeon hole in the transom

Tricks:
1) Replace the stock goudgeon screws (slotted or phillips head) w/ SS "Allen Head Cap Screws" .... you run less risk of "stripping" the screw head out ...
2) For the "new" H17/H18 Rudder system fill the hollow cavities of the "rudder cam" w/ "Marine Tex" ... this makes the cam a solid cam as the most likely failure mode is the center hole/post wearing oblong or deflecting/bending out alignment .... (scuff/sand the inside of the rudder cam cavities to promote adhesion of the Marine-Tex

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

Oh, if you wish to continue using the old system ... you can tie the rudders down w/ a 1' long piece of small line through the opening between the arm in the Upper Casting and the Lowwer Casting .... just remember to untie this line before coming to the beach/landing!!!!

(When I broke both castings that's how I managed to keep on racing .... so the day wasn't a complete loss/bummer)

I would advise ALWAYS releasing/unlocking your rudders BEFORE "hitting" the beach if you wish to keep using the "old" H18 rudder system .....

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

I've tried everything on my 1985 Hobie 18 with original castings after the rudders did not kick up and both castings broke clean in half. Shortly before that we bent a rudder arm into a nice V-shape trying to get the rudders up before a beach landing. I can tell you what kind of works and what doesn't but probably the best advice and the sure thing is to just replace them.

You'll see tons of postings about adjusting this and drilling that and what not but most solutions are just ok. Personally (this just works for me but I don't recommend it) what I find worked ok on my (now welded) rudder castings was to let the adjustment screw way out to lower tension and lubricate the cams (which I have been told you are not supposed to do). I am telling you for informational purposes only this is by no means a good solution. Just yesterday prior to getting the boat back on the trailer I had to stand on the hull directly over the rudder arm and jerk and pull straight up 2 or 3 times just to get them released.

There is no work around for using the proper equipment, which is why this will be my last season with the old castings.