Not kidding! We were out sailing on pleasant 12 - 15 knots wind and 1ft waves. Turned the wheel over to undertake a tack with the boat doing a 360 and the helm then unresponsive. I won't go into a lot of details but some are important. 1st - of course I went for the emergency tiller and when I went to install it, found the tube filled with foam which obstructed the pin. Had to dig out the foam to use the emerg. tiller. (When I bought the boat, I looked at the tube tiller and saw it was fairly rudimentary but I should have tried it out to ensure it fit and worked properly). However, the rudder was jammed from the broken pieces of disk and loose cables etc. We were not far from our home marina and got towed in from a helpful passing power boater.....earned them the best bottle of red on board. Back to the radial disk, one half of the disk was shattered in two pieces leaving the collar and other half intact on the rudder tube. Collar bolts were seized so had to cut it off. <!--break-->Upon examination I noted a 1' long section of the full length of crack on one of the pieces that was obviously an old crack as it was dark and discolored. The other cracks along the broken pieces were clean. My assessment is that because our rudder is the new model elliptical rudder (not original style found on '93 C36) and the chain and cables are quite new as well, there was at some point, impact damage/stress that caused the initial crack. Rudder, chain and cables were replaced but not the disk. From that point on, from use, the crack(s) progressed to the point where the disk shattered. I photographed the shattered disk, but don't know how to resize the photos. I'll get assistance and post them if and when I succeed in re-sizing. I almost forgot to mention and this is an important factor as well. The two bolts at the outer edge of the disk whose purpose is holding the two halves in line and tight together, were missing. I missed this in my pre-purchase inspection and so did my surveyor. New disk is on order and hope to have it in time to salvage last couple of weeks of sailing prior to haul-out.
Alain Croteau
"Veritas"
C36 #1226 SR/wk
Yanmar 3JH2
Kingston, Ontario
I was able to re-size photos of the radial drive pieces. The original crack mentioned in my 1st post is about 1" long - not 1' (typo). One half of the drive broke in two and away from the collar leaving the other half and collar still attached to the rudder tube. The 4 bolts holding the two collar halves together were seized so I had to cut the collar off.
Alain Croteau
"Veritas"
C36 #1226 SR/wk
Yanmar 3JH2
Kingston, Ontario
Thanks for sharing this. Wow, those are scary pictures. I was just inspecting/lubing my steering mechanism, but in light of your experience I think I'll go back in and have a closer look at the radial wheel.
I would be very interested to hear what Edson has to say. Was the initial crack due to a casting defect in the radial wheel?
Ken Akers
1995 C-36 MkII #1378 SR/FK M35A
San Francisco Bay
Eladio Vallina
C-36 TR EUREKA II
Hull 1122 (1991)
Home port Barcelona (Spain).
Update. New radial drive received from Edson in 5 days which was quick and appreciated. Edson had asked if the install was 'pinned' which I confirmed. They said they would bore for and supply the pin. However, only one half of the collar was bored for the pin. I assembled the two halves and carefully, with a 12" bit, bored the other half using the pre-bored hole as my quide. Turned out well. I'm not a big guy and diving in and climbing out of that aft starboard locker was not much fun. Once inside, there was good access to the rudder post and room to work. Installation of the disk went well but had a bit of a challenge centering the rudder and aligning the helm. We have a folding wheel so wanted the folded wheel as vertical as possible and with the key on top. I still think the initial small crack was due to previous rudder issue resulting in replacement. I also noted corrosion along the disk where the eye bolts lay on the disk and corrosion where the eye bolt screws into the disk. This corrosion would weaken the disk and contribute to failure.
Alain Croteau
"Veritas"
C36 #1226 SR/wk
Yanmar 3JH2
Kingston, Ontario
hi everyone, i just read Alains post with a sinking feeling. last month i dropped my rudder to inspect it for corrosion and found the same crack in my disk. fortunately my boat was on the hard so it wasn't as tramatic as his experience. i thought the crack in mine was an isolated issue but now i wonder if this isn't a manufactures defect. at the very least i would encourage everyone to give their disk and steering system a thorough once over. i'm sure grateful i discovered mine before i put my boat back in the water.
James DeBrum
S/V Slip Mistress
1984 C36 #333
Charleston S.C.
jgdebrum@gmail.com
Thank you all for this info. My boat is in the yard right now and I was not planning to drop the rudder but now I will. I have replaced the prop shaft and cutlass and Pedro tube and stuffing box and all thru hulls....
Duncan McNeill
1984 Catalina 36 #178
standard rig fin keel M25
Channel Islands
For comment: Prior to ordering the new disk, I measured the rudder tube with a micrometer which measured 2.68". When talking to Edson, they indicated that this was a standard bore and would bore it for me no extra charge. When I received the disk, I measured the dia. of the bore and although I didn't record the measurement I recall it being ever so slightly smaller than 2.68..... but I can't recall exactly what the value was. Is it possible that a very slight/miniscule difference in dia.when tightening the 4 collar bolts could cause a small stress crack that weakens the disk and when further stress is introduced by over stressing the rudder and steering, this causes shattering? I'm not an engineer so don't know how much flex/expansion the aluminum can accept/endure. Any comments? I'm at the boat for a few days early this week so will inspect the disk. I would like to talk to Edson about this but won't be able to call until next Thursday.
Alain Croteau
"Veritas"
C36 #1226 SR/wk
Yanmar 3JH2
Kingston, Ontario
A slight interference fit is normal: http://www.edsonmarine.com/support/PDFs/installation/EB380QuadrantInstr.pdf
If the interference does not exceed .005", I would not worry too much about the strain of tightening causing a crack, although it would be prudent to not grossly over tighten the machine screws as you are tightening into aluminum. Rotation load is really handled by a key, set screws, or bolts and not the clamping pressure of the machine screws.
Since four of the fasteners are stainless machine screws threaded into aluminum, they REQUIRE the use of some sort of anti-seize on the threads in order to allow for removal and, just as important, to prevent dissimilar metal corrosion.
Looking at your pictures and where the separation happened, I'd suspect dissimilar metal corrosion, perhaps magnified during whatever event that caused a rebuild of your steering system at some point, AND absolutely made worse by a substandard repair job. Clearly the steering system rebuild was not done to a high standard given the seized machine screws and the two missing edge bolts (these are vital).
This should be a wake-up call for all of us to periodically inspect our steering systems, pulling fasteners and re-applying anti-seize where dissimilar metal corrosion can happen. One of my upcoming winter projects....
Nick Caballero
Retired C36/375IA Mk II Technical Editor
This event is one more argument for a below-deck autopilot. If a steering failure occurs anywhere between the steering wheel and the radial disk, the autopilot tiller arm servo is still fully operable. You could even dock the boat with the autopilot.
Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B