Rudder replacement?

I just got back into multihulls in the last few months. Bought a solid 1980 H18 about a month ago and have been taking it out every weekend on mobile bay. Not until yesterday have I had any major problems. We were scooting along around 20kts and we started scraping bottom most likely an oyster bed. So we started depowering asap and pulling everything up. Everything was smooth until we tried to unlatch those stupid cams which until then have been easy to unlatch. Needless to say we snapped both rudders at the lower bolt. We always bring extra rope so we just lashed one rudder back on and limped back. Fixing the rudders is no problem but I'm fed up with the 2 pivot rudders on these boats and I was wondering if anybody has been able to mount single pivot rudders from other boats like lasers, fj's or 420's. I'm on a collegiate sailing team and we have an abundance of these parts or can find them for cheap. If it comes to it I will have access to a machine shop. I just wanted to know if anybody has heard of a "upgrade" like this or if anyone knows of a better way to fix this stupid design. Dropping $500+ on a "new" kit that doesn't even really fix the core problem isn't an option.

Never heard of a better system for a cat. You risk transom damage if the rudders are held down by the tiller as in the laser system.

You have original H18 metal cams? Yes, they needed a bit more loving care than the current (since 1985) system when the H18 went back to the standard plastic cams (that work quite well). If your castings didn't break, you can replace the rudders and do some maintenance on the casting. Lubrication and some light filing to smooth out a divot that appears over time. That divot holds the upper arm down when under load. The upper casting has a roll pin that slides down and locks under the cam. The divot appears on the aluminum surface forward of the cam. File that flat and always pull the tiller arms free (unlock the rudders) when heading to the beach.

The standard cam system (plastic) works great as long as you lubricate it from time to time.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Agree with the above. The current kick-up system used by Hobie works quite well and is much cleaner than using control lines to lower and hoist the rudders. But the Hobie system does require some level of regular maintenance to keep it working properly.

The old-style 18 castings can be a nuisance if not properly adjusted and maintained, but they can also be made to work effectively. In my experience, the trick is to use extremely light cam tension (so the upper casting just barely 'clicks' in), a light coating of grease on the cam/roller surfaces, and secondary bungee cord to hold the rudder down. This is the system I currently use and my rudders will kick up easily on impact.

In any case, browse through the 18 forum and you'll find several discussions on the topic.

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Doug, if it makes you feel any better i recently bought a 1980 H18 and last weekend i did the same exact thing on an oyster bed in Biloxi. Luckily, I only broke one rudder the other one came up. I had no idea these things could lock like that i thought i was going to bend the arm that comes off the casting but then it just broke. I should have just went into irons and did a dime tack but oh well you live and you learn. I'm going to try to find that piece to file down (and another rudder blade). Thanks for the tips guys.

My cams are comfortably loose they pop out easily without load on them. So lubing it up (teflon gel, 90w?) and then filing the divot off the face of the cam should fix this binding? They way I'm fixing the rudders is the way a friend did his by epoxying the broken piece back on. Then drilling two 3/8 holes and screwing all thread into them. I've heard of glassing them but I just wanted to see if there are any other ideas out there? Thanks for the help.

The divot is on the casting, opposite the cam area where the pin locks into the cam. Imagine the rudders locked down and then repeated impact of the pin on the casting surface as the rudders pull aft and or kick up. Makes a ding there. That is where the casting breaks off as well if it hits hard enough.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

There have been quite a few different types of Hobie rudders manufactured since the '80's. The material would definitely effect the repair.

If you've got solid, molded plastic rudders (Lexan, PCG) the repair you describe 'might' hold up. Not sure how well epoxy would bond to those materials. The mechanical fastening with screws could be pretty strong if there's enough material to bite into. It's a tough call and you probably won't know until you fix it and sail it.

If you've got composite rudders (EPO's, racing rudders, EPO II's) then you'll be screwing into the foam core which is going to be too weak to hold up. Plus, you'd be putting screws right into the seam line of the rudder, most likely causing it to split. You'd probably be better off bonding the broken piece back on with epoxy, grinding away most of the damaged fiberglass, and re-laminating new glass. This may or may not work. Fixing rudders is tough because you're limited in how much material you can use before the rudder won't fit into the casting anymore.

Another option is to look around for a used set of plastic rudders. You can probably find a pair for under $100.

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Would appear I have some serious wear on my old castings which lead to a broken rudder last week. Is the groove in the picture supposed to be there? Where/what should I be filing to make these things more functional? The cam itself appears to be perfectly fine, and I was able to manually release the rudders fairly easily by tugging up on the tiller cross bar (though I was always worried about them being able to kick up because I wasn't able to manually kick them up with the boat on the trailer - I should have acted on this sooner!).

This is a helpful thread for this newb. I have the same old style castings.

Matt, you mentioned to release the tiller arms when close to the beach. I assume this is to make the rudders come up more easily. But, if the tiller arms are locked down are the rudders supposed to kick up then too? I cannot pull the rudders up if they are down. I have seen attaching a fish type scale to set the springs so that about 24 lbs of force will kick the rudder up. Mine will not kick up at all.

So I am thinking I need to do some filing where the divot is, correct?

One more thing, there is quite a bit of play when the rudders are locked down. I estimate when the rudder is down the bottom of the rudder has 5-6" of play fore and aft.

_________________
1984 Hobie 18

For what it's worth, and it remains to be seen it this will work at all, I referenced the 18 next to mine which has near perfect castings of the same vintage and used that as a baseline for what I hope will be a successful repair using Home Depot epoxy plumbers putty. Basically, I thoroughly cleaned the casting to the remove grease, dirt etc and applied the "Play-Doh"-like putty into the divots until it was smooth. I have my doubts the filler will hold but the entire repair only took me around 15 minutes at a cost of ~$5 so I figured it was worth a try. I have successfully used this stuff on other projects and it dries incredibly strong. We'll see. Here's the stuff I used.....

Yes, the rudders should be able to kick up when locked down, even with the old-style 18 rudder system. If your rudders don't kick, you risk breaking the rudder, rudder pin, lower casting, or hull transom. I've written on this forum before about some of the things I've done to get the old-style system to work the way it's intended.
In summary, what you want to do is lightly grease the roller in the upper casting and the aluminum hook in the lower casting on their contact surfaces only. This may require re-application a few times per season if you sail a lot. Also, set the hook (cam) pressure screw on the bottom of the lower casting to the absolute minimum pressure required so the upper casting just "clicks" into the lower casting and stays there when the rudders are locked down. Last step, install a rudder kick-down kit. This is nothing more than a bungee cord that wraps around the rudder and rudder pin held in place with some special washers (available through Hobie or Murrays). The bungee is doing 90% of the work holding the rudder down. When you hit bottom, the rudders will kick. I've had my rudders set up this way for years and it works.

In some ways I prefer the old-style castings because there is never any issue with having the rudder cam get stuck in the wrong position or getting the cam to fully lock down.

As for the 5" of play at the tip of your rudders, this is most likely an issue of the holes in your rudders being enlarged or mislocated. Adding the rudder kick-down kit (bungee) will help eliminate some of this slop.

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I don't believe that groove is an issue. If you look at the upper casting, there are two "hooks" that catch the lower casting and hold the rudder in the up position. When you go to lock the rudder down, those hooks drag along the lower casting and cause the wear you're seeing. But those grooves shouldn't have anything to do with holding the rudder down or affecting it's release (kick-up). I suspect that any epoxy you put in there is going to get chipped out or worn down pretty quickly.

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Okay, thanks. Wasn't sure about the grooves but figured if I built them up with the epoxy putty it might help improve the efficiency of the system by putting it back to "factory spec". If anything, the "runners" on the upper casting will run a tiny bit higher as the rudders come up. Would this in any way help free the rudders to kick up? I have no idea and, frankly, I don't intend to see - I'll be manually releasing the rudders as I approach the beach going forward (No rocks, sand bars or Oyster beds to contend with where I sail, so it really isn't that big of a deal).

Take care!