C400 Rudder failure...


4speedfunk
 

I don't Facebook but, my wife does.  This morning she showed me a new thread from a Facebook C400 user group, and one of the members posted up some photos of his rudder failure.  The rudder post looks to have snapped in half just below the stuffing box. 

This guy said the initial problem was that the helms were not turning the boat.  After a closer look inside the lazerette, he noticed that the quadrant and rudder post were responding to the helms as normal but, the rudder was not...strange.  He assumed the rudder stock had separated from the internal rudder framework and was spinning inside the foam-filled rudder.  However when he pulled the rudder, only half of the rudder stock came out of the boat!  The other half stayed in place inside the lazerette...wow.  So he posted some pics of the rudder laying on the dock, and there looks to be a "tube within a tube" on the rudder stock.  The theory is that the rudder post was previously repaired by installing an internal tube sleeve inside the original tube (wtf?).  Then the outer tube had fractured into two separate pieces.  The upper half was still connected and functioning normally but, the lower half was basically stationary with the inner tube sleeve free-spinning inside the original outer tube.

I know this makes very little sense, (pics are worth a thousand words).  If you FB you should take a look...craziest thing I've ever seen.


Ken
 

I just looked at the photos and this is what I posted on FB.

It certainly does look like a splice repair but I see no evidence of welding. The original rudder post is schedule 80 2.5" pipe which is made from 304 SS. 304 SS is very suceptible to crevice corrosion and I think that may be at play here. Would like to see the upper part of the rudder post, pehaps the repair weld would be visible on that half, if so what you're seeing in the photos is a secondary failure.


Tim Francis
 

This is Tim. That’s my rudder issue. Number 180. Kolea. I was going to post on here but couldn’t figure it out. It wanted me to login and I gave up. 


On Aug 29, 2020, at 6:22 AM, Christian Wilson <wilsonmech@...> wrote:

I don't Facebook but, my wife does.  This morning she showed me a new thread from a Facebook C400 user group, and one of the members posted up some photos of his rudder failure.  The rudder post looks to have snapped in half just below the stuffing box. 

This guy said the initial problem was that the helms were not turning the boat.  After a closer look inside the lazerette, he noticed that the quadrant and rudder post were responding to the helms as normal but, the rudder was not...strange.  He assumed the rudder stock had separated from the internal rudder framework and was spinning inside the foam-filled rudder.  However when he pulled the rudder, only half of the rudder stock came out of the boat!  The other half stayed in place inside the lazerette...wow.  So he posted some pics of the rudder laying on the dock, and there looks to be a "tube within a tube" on the rudder stock.  The theory is that the rudder post was previously repaired by installing an internal tube sleeve inside the original tube (wtf?).  Then the outer tube had fractured into two separate pieces.  The upper half was still connected and functioning normally but, the lower half was basically stationary with the inner tube sleeve free-spinning inside the original outer tube.

I know this makes very little sense, (pics are worth a thousand words).  If you FB you should take a look...craziest thing I've ever seen.


Tim Francis
 




On Aug 29, 2020, at 9:49 AM, Tim Francis <Tfrancis1979@...> wrote:

This is Tim. That’s my rudder issue. Number 180. Kolea. I was going to post on here but couldn’t figure it out. It wanted me to login and I gave up. 


On Aug 29, 2020, at 6:22 AM, Christian Wilson <wilsonmech@...> wrote:

I don't Facebook but, my wife does.  This morning she showed me a new thread from a Facebook C400 user group, and one of the members posted up some photos of his rudder failure.  The rudder post looks to have snapped in half just below the stuffing box. 

This guy said the initial problem was that the helms were not turning the boat.  After a closer look inside the lazerette, he noticed that the quadrant and rudder post were responding to the helms as normal but, the rudder was not...strange.  He assumed the rudder stock had separated from the internal rudder framework and was spinning inside the foam-filled rudder.  However when he pulled the rudder, only half of the rudder stock came out of the boat!  The other half stayed in place inside the lazerette...wow.  So he posted some pics of the rudder laying on the dock, and there looks to be a "tube within a tube" on the rudder stock.  The theory is that the rudder post was previously repaired by installing an internal tube sleeve inside the original tube (wtf?).  Then the outer tube had fractured into two separate pieces.  The upper half was still connected and functioning normally but, the lower half was basically stationary with the inner tube sleeve free-spinning inside the original outer tube.

I know this makes very little sense, (pics are worth a thousand words).  If you FB you should take a look...craziest thing I've ever seen.


Tom Sokoloski
 

Tim,
Do you have any pix of the other piece of the rudder post?  The part that was still in the tube?

Tom Soko
Juniper #307
Noank, CT

--
Tom Soko
Juniper #307
Noank, CT


Ken
 

Actually it's amazing that the rudder had to be pulled. It was only held in by the lower bearing and whatever friction the sleeve and the top of the rudder post presented. Warren Pandy told me once that the rudder assembly has almost neutral bouyancy so maybe that helped to keep it in place.

Tim please post pictures of the top part of the rudder post when you pull it.

Ken
ex 245


Tim Francis
 

I’m having a hard time getting the top part of the broken shaft out. Granted, I’m using a claw hammer and an impact socket. I’m worried about flaring the sides. The quadrant is loose from the shaft. The stuffing box is loose. It’s just real tight at the top. There’s a collar that’s bolted on top of the quadrant. I did not loosen that because I think it’s only there to hold the shaft in place. Before I get a sledge and something more fitting to knock the shaft back down more, I want to ask if I’m missing something. I think it just needs more yelling at and beatings with a sledge. I knocked it down over an inch but seems to not want to go more now without excessive force. Shoukd I get a bigger sledge and keep beating it till it drops down to the bottom of the slip. ? 


On Aug 29, 2020, at 11:02 AM, Ken <kdg_1@...> wrote:

Actually it's amazing that the rudder had to be pulled. It was only held in by the lower bearing and whatever friction the sleeve and the top of the rudder post presented. Warren Pandy told me once that the rudder assembly has almost neutral bouyancy so maybe that helped to keep it in place.

Tim please post pictures of the top part of the rudder post when you pull it.

Ken
ex 245


Tim Francis
 




On Aug 29, 2020, at 11:30 AM, Tim Francis <Tfrancis1979@...> wrote:

I’m having a hard time getting the top part of the broken shaft out. Granted, I’m using a claw hammer and an impact socket. I’m worried about flaring the sides. The quadrant is loose from the shaft. The stuffing box is loose. It’s just real tight at the top. There’s a collar that’s bolted on top of the quadrant. I did not loosen that because I think it’s only there to hold the shaft in place. Before I get a sledge and something more fitting to knock the shaft back down more, I want to ask if I’m missing something. I think it just needs more yelling at and beatings with a sledge. I knocked it down over an inch but seems to not want to go more now without excessive force. Shoukd I get a bigger sledge and keep beating it till it drops down to the bottom of the slip. ? 


On Aug 29, 2020, at 11:02 AM, Ken <kdg_1@...> wrote:

Actually it's amazing that the rudder had to be pulled. It was only held in by the lower bearing and whatever friction the sleeve and the top of the rudder post presented. Warren Pandy told me once that the rudder assembly has almost neutral bouyancy so maybe that helped to keep it in place.

Tim please post pictures of the top part of the rudder post when you pull it.

Ken
ex 245


Ken
 

Tim,

Thanks for posting this issue and the photos of the top half of the rudder post.  But it seems to beg more questions that only Warren Pandy can answer.  Here are my thoughts based on your two sets of photographs and the sketch provided by Nick Walker of the internal design of the rudder. Nick's sketch is on the other half of this bifurcated site.
- There seems to be no evidence of any welding for a prior sleeve repair of the rudder post on either half of the rudder.
- The break in the rudder post appers to be entirely due to crevice corrosion of the 304SS.
- The rudder post has an inner sleeve at the lower end. Does it possiblely extend all the way to the bottom of the rudder post? Was it pressed in at the factory to serve as a reinforcement of the lower portion of the rudder where the welds are for the creation of the internal webbing?
- Nick's drawing illustrates an unusual rudder design, at least to me. All of the rudders I've repaired have had the rudder post go much further down into the rudder.  Maybe that's why Warren told me the C400 rudder is bouyancy neutral, there's much less SS inside the rudder cavity.

A point for all C400 members from Tim's photos is the effect of crevice corrosion on SS rudder post not exposed to the air.  Well Tim are you leaning toward repair or replacement? 


Tim Francis
 

I’m out dingy fishing right now in rough conditions. I’ll answer this when I get back to kolea. 


On Aug 30, 2020, at 7:40 AM, Ken <kdg_1@...> wrote:

Tim,

Thanks for posting this issue and the photos of the top half of the rudder post.  But it seems to beg more questions that only Warren Pandy can answer.  Here are my thoughts based on your two sets of photographs and the sketch provided by Nick Walker of the internal design of the rudder. Nick's sketch is on the other half of this bifurcated site.
- There seems to be no evidence of any welding for a prior sleeve repair of the rudder post on either half of the rudder.
- The break in the rudder post appers to be entirely due to crevice corrosion of the 304SS.
- The rudder post has an inner sleeve at the lower end. Does it possiblely extend all the way to the bottom of the rudder post? Was it pressed in at the factory to serve as a reinforcement of the lower portion of the rudder where the welds are for the creation of the internal webbing?
- Nick's drawing illustrates an unusual rudder design, at least to me. All of the rudders I've repaired have had the rudder post go much further down into the rudder.  Maybe that's why Warren told me the C400 rudder is bouyancy neutral, there's much less SS inside the rudder cavity.

A point for all C400 members from Tim's photos is the effect of crevice corrosion on SS rudder post not exposed to the air.  Well Tim are you leaning toward repair or replacement? 


bajankiwi
 

I too had this exact thing occur on my boat two years ago, during the middle of a race. We collided in big seas with a competitor, causing quite some damage. We could not make head nor tail of the rudder design, as we had assumed the design consisted of a solid tube of stainless. Nope, it’s two tubes of different diameter that seemed tack welded together and we believe that the welds had failed. Upon removing the rudder we found quite a bit of water ingress to the top of the rudder where the tube enters. We disassembled the rudder which made it unwise to rebuild it. We instead built a replacement from scratch.
I would recommend all owners take a good look at the rudder integrity when next you get a chance
The twin helm stations that make our boats a delight to sail do have the consequence of quite a complex steering system and it is well worth having someone knowledgeable take a good look to ensure nothing that Caused our collision happens to your boat.
Ian
Ten Seven

On 30/08/2020, at 1:40 PM, Ken <kdg_1@...> wrote:


Tim Francis
 

I’m looking at getting it welded back together, inserting tapped set screws above and below the break/ weld.

Did insurance cover your sheared rudder like mine?

I’ll install the rudder myself and hope I can get it in place easily. It will be a somewhat temporary fix till I figure out what to do for permanent 20 year fix. Maybe rebuild this rudder with new shaft or buy a new rudder. I’m broke as a joke as a captain with no unemployment or income. I also have had the worse experience on Oahu. I just want to get away from Honolulu area.

Depending on what happens tomorrow as far as deciding to get it welded or rebuilt here for a more permanent fix, I plan on getting hauled out on big island which I am beyond comfortable with unlike here on Oahu. This place makes me sick.

Question

If I get the rudder rebuilt on Oahu for around 3 k, shoukd I buy the two new bearings?

I know the answer but wNt confirmation.

When I loosened the quadrant, I went underwater to see if I coukd try to slide down the shaft. Still thinking the armature was broke, I was incredibly surprised a was able to dislodge the shaft. The rudder floated up with the top of the broken shaft hitting the hull, no damage but maybe bottom paint scratch, it hit then righted itself and floated easily next to kolea. It was not neutral buoyant.
It floated easily. If I had to guess, without the top part of the broken shaft, I coukd stand on the rudder at 200 lbs and it would slowly sink possibly. Lucky it was positively bouyant. So it stayed in the shaft log and didn’t sink. I wish I knew a month ago it snapped. I could have saved a month of waiting on repair estimates. I was -
99.99 percent sure it was broken armature. I said that somewhere in a forum but didn’t want to give the extra .01 percent.
When I started hammering the top part of the broken shaft, I got about an inch plus to drop. It wasn’t going any further down. Before I went with a bigger sledge than the claw hammer and a bigger socket or pipe to put on top of the shaft to beat the he’ll out of it, I paused, went down under water, and noticed the ridged shear cut, was caught on the top of the upper bearing, I was a little lazy and had the quadrant loose but not loose enough, I had a neighbor hammering whike I was in the water and didn’t realize the quadrant was still too tight, I had two of the upper quadrant of the four bolts break off. So I drilled them out but not all the way. So one side of the quadrant was loose enough but not the other side because of the broken heads of the bolts that I half asses drilled out. It resulted in the shaft not dropping strait through the lower bearing. So I got my crow bar and whike my neighbor was whacking, I was positioning the upper part of the broken shaft to drop in the bearing hole, not catch on the top of the bearing, I had already took out the screws holding up the lower bearing with basically me saying screw it, I’ll pop the bearing out with the upper shaft cause I knew I already caused scoring on the bearing top from broken jagged lower end of upper broken shaft.

Right now the bearing is halfway popped out. I Havnt decided what to do yet with that. Probly take it off the boat to fit on the shaft before I try sticking the welded makeshift repair to the shaft in the rudder log.


Sorry for the long explanation. But I think it’s important to spread the word even if you have to read my jibberish a few times to understand.

Not to be a nerdy nelly, but it coukd be a life or death consequence if another snaps in a crossing or Winward side etc.

I wonder how many catslina 400 rudders broke the same way?

I wonder how many will?

I wonder how many are operating with a crack or intrusion without the owner knowing.


If you look at the pics of the broken shaft, it looks like maybe some part of the pipe is rusty and some a clean break. So my point is, it may have been fractured or cracked for a while and finally gave out.

I have made several channel crossings in foul weather between the Hawaiian islands with zero problems.

A week before the rudder failed, I crossed from Maui to Oahu in for today’s six foot following/ starboard aft corner seas. It was pretty big but rolly. Nothing super crazy but I figured it would have snapped on one of the bigger six footers. Legit six foot. Not make believe six foot. Some sevens.
I made it in fine, a week later I was a mile or two off Waikiki bottomfishing in maybe one foot seas drifting. I made about four drifts at half a mile or so then when I dropped off my target depth, I fired up my best girlfriend, Yanmarie, my trusted 4jht3 and no rudder response. I could go port if I remember right but not starboard. I looked at the quadrNt, it was turning correct with the cables. I looked at the shaft turning with the quadrant. Looked good. But the rudder wasn’t responding. I got a tow in and then concluded the 99.99 percent it was the armature. I contacted a local repair place here, it took a month or a little tiny less to get a repair estimate at 12.5 k. With a new rudder and Haulout. Well that’s a lot on captain pay.

So I think for once in my life, a diy job will actually pay off and not cost me double what I tried to save.

Mahalo for the long read.

Aloha y’all.

On Aug 30, 2020, at 12:23 PM, bajankiwi <cubatea@...> wrote:

I too had this exact thing occur on my boat two years ago, during the middle of a race. We collided in big seas with a competitor, causing quite some damage. We could not make head nor tail of the rudder design, as we had assumed the design consisted of a solid tube of stainless. Nope, it’s two tubes of different diameter that seemed tack welded together and we believe that the welds had failed. Upon removing the rudder we found quite a bit of water ingress to the top of the rudder where the tube enters. We disassembled the rudder which made it unwise to rebuild it. We instead built a replacement from scratch.
I would recommend all owners take a good look at the rudder integrity when next you get a chance
The twin helm stations that make our boats a delight to sail do have the consequence of quite a complex steering system and it is well worth having someone knowledgeable take a good look to ensure nothing that Caused our collision happens to your boat.
Ian
Ten Seven

On 30/08/2020, at 1:40 PM, Ken <kdg_1@...> wrote:


4speedfunk
 

Holy smokes.  This is quite concerning as the break occured at a point on the shaft where even an emergency tiller will not have saved you.  I agree that it looks like there was corrosion at the break for some time before it actually separated.  This is evident by the pics of the rudder laying on the dock.  Certainly an impact (grounding) would do this but, perhaps side-loading from large seas could fatigue the shaft over time?  Another scenario that comes to mind is "letting go of the helm while reversing".  This is known among sailors to be a huge no-no but, I still see charter captains doing this.  Letting go of the helm in reverse will allow the rudder to be slammed all the way to full lock (90-degrees to the force of flow), and this puts enormous stress on the rudder.  I suppose doing this repeatedly in each direction could shock the rudder post enough to cause cracks, especially since we don't have any sort of skeg.  Regardless of the cause, this is definitely going to warrant me to take a closer look at mine.  I will use some machine dye on mine the next time I pull it...any problems will be very obvious as the dye will creep into any microscopic cracks on the post.

Tube or Pipe?
Someone mentioned the rudder stock could be "schedule 80 pipe" and that is equally concerning.  That is totally the wrong choice for fabbing something like this.  A critical (life dependent) item like this should be fabbed from "tube".  The two materials are similar in appearance but, tube has structural properties that pipe does not.  Sometimes pipe is used for non-critical things like architecutral railings or for doing mock-ups because it is far cheaper.  But, pipe should never be used for something like this.  Tube has a tighter dimensional tolerance than pipe, and it can be purchased with any number of wall thicknesses or alloys to fit whatever purpose the engineer is targeting. Pipe is intended to transport liquids...period.  Thats why it is specifically selected by ID.  That being said...the dimensions of the C400 rudder stock do point to it being 2-1/2" Schedule 80 pipe, (yikes!).  I know this because I recently fabbed my own Delrin rudder bushings and the finished ID of the bushings was 2.880".  This dimension includes the recommended .005" oversize clearance for Delrin...which matches the listed OD of 2-1/2" Schedule 80 pipe (OD=2.875").  So as much as I hate to admit it...the C400 rudder post IS indeed made from pipe and not tube.

Other comments:
  1. The bearings should probably be replaced.  The Catalina Direct kit should work fine with your MK II boat, (it also comes with a new stuffing box / middle bearing).
  2. The screws falling out of the lower bearing is a common problem.  Catalina recommends gluing the lower bearing in place with 5200 (on the flange only).  Not sure how this will work underwater.  Allegedly, the four screws on the flange are there only to clamp the bearing to the hull, until the 5200 dries.
  3. There are set-screws on the rudder tube at the stuffing box and lower bearing locations.  These should be "snugged" to hold these pieces in place and prevent them from turning...do not over-tighten these.
  4. Do I see a countersunk allen bolt in the post about four inches above the rudder?  Perhaps this is what attaches the inner sleeve to the outer pipe?
Now what?
Great question.  I personally would rebuild the post using some 316L SS tube...probably go with 1/2" wall, or maybe even solid bar stock.  If the existing post is still robustly attached to the rudder...you might be able to mate a new tube (or bar) to the stub that is protruding from the top of the rudder.  Try to keep the original stub as long as possible.  You will need to machine the new post to fit down over the stub.  Get rid of the countersunk allen bolt and instead weld the stub to the new post using numerous rosette welds.  You will need to grind or lathe these welds afterwards to keep the surface of the post smooth.  After all this, cross-drill new holes for the upper retaining bolt, quadrant, and autopilot...matching the same clocking angle as the original.  Lastly...slam it together with new bushings and stuffing box.  Easier said than done.

The new tube (or bar) will be expensive, and it may be hard to find a qualified shop to do the work.  I have access to a really large lathe (that once built P51's in WWII), and it has enough clearance for the rudder to swing as it spins.  This would make mating the old stub to the new post much easier but, I realize you may be stuck with hand tools.  It can be done, it just takes alot more effort.

Or you could just call Catalina and buy a new OEM rudder.


Tim Francis
 

Catalina didn’t offer any discounts or a free rudder. They said in 30 years, they never saw a failure like this in any of their rudders. 
I’m dropping the rudder off to get welded now. 


On Aug 31, 2020, at 4:42 AM, Christian Wilson <wilsonmech@...> wrote:

Holy smokes.  This is quite concerning as the break occured at a point on the shaft where even an emergency tiller will not have saved you.  I agree that it looks like there was corrosion at the break for some time before it actually separated.  This is evident by the pics of the rudder laying on the dock.  Certainly an impact (grounding) would do this but, perhaps side-loading from large seas could fatigue the shaft over time?  Another scenario that comes to mind is "letting go of the helm while reversing".  This is known among sailors to be a huge no-no but, I still see charter captains doing this.  Letting go of the helm in reverse will allow the rudder to be slammed all the way to full lock (90-degrees to the force of flow), and this puts enormous stress on the rudder.  I suppose doing this repeatedly in each direction could shock the rudder post enough to cause cracks, especially since we don't have any sort of skeg.  Regardless of the cause, this is definitely going to warrant me to take a closer look at mine.  I will use some machine dye on mine the next time I pull it...any problems will be very obvious as the dye will creep into any microscopic cracks on the post.

Tube or Pipe?
Someone mentioned the rudder stock could be "schedule 80 pipe" and that is equally concerning.  That is totally the wrong choice for fabbing something like this.  A critical (life dependent) item like this should be fabbed from "tube".  The two materials are similar in appearance but, tube has structural properties that pipe does not.  Sometimes pipe is used for non-critical things like architecutral railings or for doing mock-ups because it is far cheaper.  But, pipe should never be used for something like this.  Tube has a tighter dimensional tolerance than pipe, and it can be purchased with any number of wall thicknesses or alloys to fit whatever purpose the engineer is targeting. Pipe is intended to transport liquids...period.  Thats why it is specifically selected by ID.  That being said...the dimensions of the C400 rudder stock do point to it being 2-1/2" Schedule 80 pipe, (yikes!).  I know this because I recently fabbed my own Delrin rudder bushings and the finished ID of the bushings was 2.880".  This dimension includes the recommended .005" oversize clearance for Delrin...which matches the listed OD of 2-1/2" Schedule 80 pipe (OD=2.875").  So as much as I hate to admit it...the C400 rudder post IS indeed made from pipe and not tube.

Other comments:
  1. The bearings should probably be replaced.  The Catalina Direct kit should work fine with your MK II boat, (it also comes with a new stuffing box / middle bearing).
  2. The screws falling out of the lower bearing is a common problem.  Catalina recommends gluing the lower bearing in place with 5200 (on the flange only).  Not sure how this will work underwater.  Allegedly, the four screws on the flange are there only to clamp the bearing to the hull, until the 5200 dries.
  3. There are set-screws on the rudder tube at the stuffing box and lower bearing locations.  These should be "snugged" to hold these pieces in place and prevent them from turning...do not over-tighten these.
  4. Do I see a countersunk allen bolt in the post about four inches above the rudder?  Perhaps this is what attaches the inner sleeve to the outer pipe?
Now what?
Great question.  I personally would rebuild the post using some 316L SS tube...probably go with 1/2" wall, or maybe even solid bar stock.  If the existing post is still robustly attached to the rudder...you might be able to mate a new tube (or bar) to the stub that is protruding from the top of the rudder.  Try to keep the original stub as long as possible.  You will need to machine the new post to fit down over the stub.  Get rid of the countersunk allen bolt and instead weld the stub to the new post using numerous rosette welds.  You will need to grind or lathe these welds afterwards to keep the surface of the post smooth.  After all this, cross-drill new holes for the upper retaining bolt, quadrant, and autopilot...matching the same clocking angle as the original.  Lastly...slam it together with new bushings and stuffing box.  Easier said than done.

The new tube (or bar) will be expensive, and it may be hard to find a qualified shop to do the work.  I have access to a really large lathe (that once built P51's in WWII), and it has enough clearance for the rudder to swing as it spins.  This would make mating the old stub to the new post much easier but, I realize you may be stuck with hand tools.  It can be done, it just takes alot more effort.

Or you could just call Catalina and buy a new OEM rudder.


Tim Francis
 

Got the shaft welded together. Drilled holes and spot welded the outer to inner. Lower bearing slides over the shaft easy. Putting it in tomorrow 


On Aug 31, 2020, at 2:20 PM, Tim Francis <Tfrancis1979@...> wrote:

Catalina didn’t offer any discounts or a free rudder. They said in 30 years, they never saw a failure like this in any of their rudders. 
I’m dropping the rudder off to get welded now. 


On Aug 31, 2020, at 4:42 AM, Christian Wilson <wilsonmech@...> wrote:

Holy smokes.  This is quite concerning as the break occured at a point on the shaft where even an emergency tiller will not have saved you.  I agree that it looks like there was corrosion at the break for some time before it actually separated.  This is evident by the pics of the rudder laying on the dock.  Certainly an impact (grounding) would do this but, perhaps side-loading from large seas could fatigue the shaft over time?  Another scenario that comes to mind is "letting go of the helm while reversing".  This is known among sailors to be a huge no-no but, I still see charter captains doing this.  Letting go of the helm in reverse will allow the rudder to be slammed all the way to full lock (90-degrees to the force of flow), and this puts enormous stress on the rudder.  I suppose doing this repeatedly in each direction could shock the rudder post enough to cause cracks, especially since we don't have any sort of skeg.  Regardless of the cause, this is definitely going to warrant me to take a closer look at mine.  I will use some machine dye on mine the next time I pull it...any problems will be very obvious as the dye will creep into any microscopic cracks on the post.

Tube or Pipe?
Someone mentioned the rudder stock could be "schedule 80 pipe" and that is equally concerning.  That is totally the wrong choice for fabbing something like this.  A critical (life dependent) item like this should be fabbed from "tube".  The two materials are similar in appearance but, tube has structural properties that pipe does not.  Sometimes pipe is used for non-critical things like architecutral railings or for doing mock-ups because it is far cheaper.  But, pipe should never be used for something like this.  Tube has a tighter dimensional tolerance than pipe, and it can be purchased with any number of wall thicknesses or alloys to fit whatever purpose the engineer is targeting. Pipe is intended to transport liquids...period.  Thats why it is specifically selected by ID.  That being said...the dimensions of the C400 rudder stock do point to it being 2-1/2" Schedule 80 pipe, (yikes!).  I know this because I recently fabbed my own Delrin rudder bushings and the finished ID of the bushings was 2.880".  This dimension includes the recommended .005" oversize clearance for Delrin...which matches the listed OD of 2-1/2" Schedule 80 pipe (OD=2.875").  So as much as I hate to admit it...the C400 rudder post IS indeed made from pipe and not tube.

Other comments:
  1. The bearings should probably be replaced.  The Catalina Direct kit should work fine with your MK II boat, (it also comes with a new stuffing box / middle bearing).
  2. The screws falling out of the lower bearing is a common problem.  Catalina recommends gluing the lower bearing in place with 5200 (on the flange only).  Not sure how this will work underwater.  Allegedly, the four screws on the flange are there only to clamp the bearing to the hull, until the 5200 dries.
  3. There are set-screws on the rudder tube at the stuffing box and lower bearing locations.  These should be "snugged" to hold these pieces in place and prevent them from turning...do not over-tighten these.
  4. Do I see a countersunk allen bolt in the post about four inches above the rudder?  Perhaps this is what attaches the inner sleeve to the outer pipe?
Now what?
Great question.  I personally would rebuild the post using some 316L SS tube...probably go with 1/2" wall, or maybe even solid bar stock.  If the existing post is still robustly attached to the rudder...you might be able to mate a new tube (or bar) to the stub that is protruding from the top of the rudder.  Try to keep the original stub as long as possible.  You will need to machine the new post to fit down over the stub.  Get rid of the countersunk allen bolt and instead weld the stub to the new post using numerous rosette welds.  You will need to grind or lathe these welds afterwards to keep the surface of the post smooth.  After all this, cross-drill new holes for the upper retaining bolt, quadrant, and autopilot...matching the same clocking angle as the original.  Lastly...slam it together with new bushings and stuffing box.  Easier said than done.

The new tube (or bar) will be expensive, and it may be hard to find a qualified shop to do the work.  I have access to a really large lathe (that once built P51's in WWII), and it has enough clearance for the rudder to swing as it spins.  This would make mating the old stub to the new post much easier but, I realize you may be stuck with hand tools.  It can be done, it just takes alot more effort.

Or you could just call Catalina and buy a new OEM rudder.


Tim Francis
 




On Aug 31, 2020, at 6:53 PM, Tim Francis <Tfrancis1979@...> wrote:

Got the shaft welded together. Drilled holes and spot welded the outer to inner. Lower bearing slides over the shaft easy. Putting it in tomorrow 


On Aug 31, 2020, at 2:20 PM, Tim Francis <Tfrancis1979@...> wrote:

Catalina didn’t offer any discounts or a free rudder. They said in 30 years, they never saw a failure like this in any of their rudders. 
I’m dropping the rudder off to get welded now. 


On Aug 31, 2020, at 4:42 AM, Christian Wilson <wilsonmech@...> wrote:

Holy smokes.  This is quite concerning as the break occured at a point on the shaft where even an emergency tiller will not have saved you.  I agree that it looks like there was corrosion at the break for some time before it actually separated.  This is evident by the pics of the rudder laying on the dock.  Certainly an impact (grounding) would do this but, perhaps side-loading from large seas could fatigue the shaft over time?  Another scenario that comes to mind is "letting go of the helm while reversing".  This is known among sailors to be a huge no-no but, I still see charter captains doing this.  Letting go of the helm in reverse will allow the rudder to be slammed all the way to full lock (90-degrees to the force of flow), and this puts enormous stress on the rudder.  I suppose doing this repeatedly in each direction could shock the rudder post enough to cause cracks, especially since we don't have any sort of skeg.  Regardless of the cause, this is definitely going to warrant me to take a closer look at mine.  I will use some machine dye on mine the next time I pull it...any problems will be very obvious as the dye will creep into any microscopic cracks on the post.

Tube or Pipe?
Someone mentioned the rudder stock could be "schedule 80 pipe" and that is equally concerning.  That is totally the wrong choice for fabbing something like this.  A critical (life dependent) item like this should be fabbed from "tube".  The two materials are similar in appearance but, tube has structural properties that pipe does not.  Sometimes pipe is used for non-critical things like architecutral railings or for doing mock-ups because it is far cheaper.  But, pipe should never be used for something like this.  Tube has a tighter dimensional tolerance than pipe, and it can be purchased with any number of wall thicknesses or alloys to fit whatever purpose the engineer is targeting. Pipe is intended to transport liquids...period.  Thats why it is specifically selected by ID.  That being said...the dimensions of the C400 rudder stock do point to it being 2-1/2" Schedule 80 pipe, (yikes!).  I know this because I recently fabbed my own Delrin rudder bushings and the finished ID of the bushings was 2.880".  This dimension includes the recommended .005" oversize clearance for Delrin...which matches the listed OD of 2-1/2" Schedule 80 pipe (OD=2.875").  So as much as I hate to admit it...the C400 rudder post IS indeed made from pipe and not tube.

Other comments:
  1. The bearings should probably be replaced.  The Catalina Direct kit should work fine with your MK II boat, (it also comes with a new stuffing box / middle bearing).
  2. The screws falling out of the lower bearing is a common problem.  Catalina recommends gluing the lower bearing in place with 5200 (on the flange only).  Not sure how this will work underwater.  Allegedly, the four screws on the flange are there only to clamp the bearing to the hull, until the 5200 dries.
  3. There are set-screws on the rudder tube at the stuffing box and lower bearing locations.  These should be "snugged" to hold these pieces in place and prevent them from turning...do not over-tighten these.
  4. Do I see a countersunk allen bolt in the post about four inches above the rudder?  Perhaps this is what attaches the inner sleeve to the outer pipe?
Now what?
Great question.  I personally would rebuild the post using some 316L SS tube...probably go with 1/2" wall, or maybe even solid bar stock.  If the existing post is still robustly attached to the rudder...you might be able to mate a new tube (or bar) to the stub that is protruding from the top of the rudder.  Try to keep the original stub as long as possible.  You will need to machine the new post to fit down over the stub.  Get rid of the countersunk allen bolt and instead weld the stub to the new post using numerous rosette welds.  You will need to grind or lathe these welds afterwards to keep the surface of the post smooth.  After all this, cross-drill new holes for the upper retaining bolt, quadrant, and autopilot...matching the same clocking angle as the original.  Lastly...slam it together with new bushings and stuffing box.  Easier said than done.

The new tube (or bar) will be expensive, and it may be hard to find a qualified shop to do the work.  I have access to a really large lathe (that once built P51's in WWII), and it has enough clearance for the rudder to swing as it spins.  This would make mating the old stub to the new post much easier but, I realize you may be stuck with hand tools.  It can be done, it just takes alot more effort.

Or you could just call Catalina and buy a new OEM rudder.


Ron Groth
 


Would also recommend welding in a stainless pin, as well as welding back together and grinding flush.

Ron
Elixir hull 37

On Tuesday, September 1, 2020, 02:09:08 AM EDT, Tim Francis <tfrancis1979@...> wrote:





On Aug 31, 2020, at 6:53 PM, Tim Francis <Tfrancis1979@...> wrote:

 Got the shaft welded together. Drilled holes and spot welded the outer to inner. Lower bearing slides over the shaft easy. Putting it in tomorrow 


On Aug 31, 2020, at 2:20 PM, Tim Francis <Tfrancis1979@...> wrote:

 Catalina didn’t offer any discounts or a free rudder. They said in 30 years, they never saw a failure like this in any of their rudders. 
I’m dropping the rudder off to get welded now. 


On Aug 31, 2020, at 4:42 AM, Christian Wilson <wilsonmech@...> wrote:

Holy smokes.  This is quite concerning as the break occured at a point on the shaft where even an emergency tiller will not have saved you.  I agree that it looks like there was corrosion at the break for some time before it actually separated.  This is evident by the pics of the rudder laying on the dock.  Certainly an impact (grounding) would do this but, perhaps side-loading from large seas could fatigue the shaft over time?  Another scenario that comes to mind is "letting go of the helm while reversing".  This is known among sailors to be a huge no-no but, I still see charter captains doing this.  Letting go of the helm in reverse will allow the rudder to be slammed all the way to full lock (90-degrees to the force of flow), and this puts enormous stress on the rudder.  I suppose doing this repeatedly in each direction could shock the rudder post enough to cause cracks, especially since we don't have any sort of skeg.  Regardless of the cause, this is definitely going to warrant me to take a closer look at mine.  I will use some machine dye on mine the next time I pull it...any problems will be very obvious as the dye will creep into any microscopic cracks on the post.

Tube or Pipe?
Someone mentioned the rudder stock could be "schedule 80 pipe" and that is equally concerning.  That is totally the wrong choice for fabbing something like this.  A critical (life dependent) item like this should be fabbed from "tube".  The two materials are similar in appearance but, tube has structural properties that pipe does not.  Sometimes pipe is used for non-critical things like architecutral railings or for doing mock-ups because it is far cheaper.  But, pipe should never be used for something like this.  Tube has a tighter dimensional tolerance than pipe, and it can be purchased with any number of wall thicknesses or alloys to fit whatever purpose the engineer is targeting. Pipe is intended to transport liquids...period.  Thats why it is specifically selected by ID.  That being said...the dimensions of the C400 rudder stock do point to it being 2-1/2" Schedule 80 pipe, (yikes!).  I know this because I recently fabbed my own Delrin rudder bushings and the finished ID of the bushings was 2.880".  This dimension includes the recommended .005" oversize clearance for Delrin...which matches the listed OD of 2-1/2" Schedule 80 pipe (OD=2.875").  So as much as I hate to admit it...the C400 rudder post IS indeed made from pipe and not tube.

Other comments:
  1. The bearings should probably be replaced.  The Catalina Direct kit should work fine with your MK II boat, (it also comes with a new stuffing box / middle bearing).
  2. The screws falling out of the lower bearing is a common problem.  Catalina recommends gluing the lower bearing in place with 5200 (on the flange only).  Not sure how this will work underwater.  Allegedly, the four screws on the flange are there only to clamp the bearing to the hull, until the 5200 dries.
  3. There are set-screws on the rudder tube at the stuffing box and lower bearing locations.  These should be "snugged" to hold these pieces in place and prevent them from turning...do not over-tighten these.
  4. Do I see a countersunk allen bolt in the post about four inches above the rudder?  Perhaps this is what attaches the inner sleeve to the outer pipe?
Now what?
Great question.  I personally would rebuild the post using some 316L SS tube...probably go with 1/2" wall, or maybe even solid bar stock.  If the existing post is still robustly attached to the rudder...you might be able to mate a new tube (or bar) to the stub that is protruding from the top of the rudder.  Try to keep the original stub as long as possible.  You will need to machine the new post to fit down over the stub.  Get rid of the countersunk allen bolt and instead weld the stub to the new post using numerous rosette welds.  You will need to grind or lathe these welds afterwards to keep the surface of the post smooth.  After all this, cross-drill new holes for the upper retaining bolt, quadrant, and autopilot...matching the same clocking angle as the original.  Lastly...slam it together with new bushings and stuffing box.  Easier said than done.

The new tube (or bar) will be expensive, and it may be hard to find a qualified shop to do the work.  I have access to a really large lathe (that once built P51's in WWII), and it has enough clearance for the rudder to swing as it spins.  This would make mating the old stub to the new post much easier but, I realize you may be stuck with hand tools.  It can be done, it just takes alot more effort.

Or you could just call Catalina and buy a new OEM rudder.


Ken
 

Tim,

From the photos it looks like the welder did a nice job repairing the rudder post.  Have you considered passivating the post before you return it to service?  It will help to a certain degree to prevent the type of corrosion that you experienced.

I hope the reinstall goes smoothly.

Ken


4speedfunk
 

I never thought of re-using the same rudder post...just assumed it was trashed from the failure (and the hammering).  But, now that I see it on the workbench it looks totally acceptable.

Also now that its on the bench, its pretty apparent that the failure of the rudder post occurred along a crack between the original plug welds.  Rust & corrosion can clearly be seen between the innner and outer tubes, around the original weld.  Looks to have been that way for a long time.  Anyway, it looks like a great fix (fast and reasonably cheap compared to a total replacement).  Definitely post up some details on how you get that thing back in place with the boat in the water.  Somehow weigh it down to get the post back into the rudder tube?  Hopefully you have eight feet of water at your slip.  Good job.


Tim Francis
 

I don’t know what passivating it is. 


On Sep 1, 2020, at 4:57 AM, Ken <kdg_1@...> wrote:

Tim,

From the photos it looks like the welder did a nice job repairing the rudder post.  Have you considered passivating the post before you return it to service?  It will help to a certain degree to prevent the type of corrosion that you experienced.

I hope the reinstall goes smoothly.

Ken