Rudder problem - fatcup is broken

[Segelplaner]

Hi!
We probably have a major rudderproblem.
The fatcup is off because the heartstock has been moving (I think).
I guess we have to rebuild the rudder, some parts that is probably broken. We think that this problem started earlier and a chain of events finally broke the fatcup. We also had minor leakage from fatcup.

Luckily we just took up the boat for some bottom painting.

What is the suggested action?



Thanks
Jonas

[Sailmonkey]

Maybe I’m showing my ignorance here....

Fatcup?

Heartstock?

What is that thing in the photo?

[Segelplaner]

Sorry, dont know the accurate english words for parts of rudder system.
The thing on photo is the fat-cup, there you put in grease/fat for the rudder.
Heartstock (my swedish-english) is where the grease is put thorough fat-cup to make the rudder go smoother.
Heartstock is one of the central parts of the rudder system and something like bearings or similar is probably broken too and the main-cause.
The rudder have also been more ”tight” in one direction when moving steering-wheel.

[Woodland Hills]

Rudderstock and greasecup would be a more accurate translation.

[cal40john]

Retap the threads where the grease cup fell out, put a plug in, drill a new hole the right size for a zerk fitting, tap and install.
Have someone check rudder bearings for damage and bent rudder shaft.
I don't have bearings, but I don't see why bearings in water on a low/slow motion rudder would be damaged, other than marine growth, or corrosion, but aren't they all plastic?

I have two grease cups, no rudder bearings, they're screwed into the fiberglass tube surrounding the rudderpost from hull to deck.

[Segelplaner]

Thanks - will use term rudderstock from now on
Sounds like resonable causes - marine growth or corrosion.
We are on a long journey which started in Stockholm - now we are in Antigua/Carribean.
This is a total new environment for the boat that are "used" to brackish waters.

We think the problem started somewhere in the middle of the Atlantic passage some months ago. The greasecup started to leak.
Also the parts of the rudder which are inside the boat and under our beds - started to make scratches on some wood.

All this together seem to show that the rudder is not "stable" and "moving".

I don't know how this rudder is constructed inside rudderstock, but will surely find out.
I have found an "rudderexpert" that comes tomorrow and help us out.

Thanks for all good input!

[Segelplaner]

F.Y.I.
Found this info from Jefa that I think are the rudderstock/rudder supplier:
https://www.jefa.com/electro-f.htm

Jonas

[TrentePieds]

Jonas:

Quote: “I don't know how this rudder is constructed inside rudder stock...”

Here is a link to a very good introductory article on how the rudder in a boat like yours is constructed and mounted in the hull of the boat:

https://www.sailmagazine.com/diy/know-your-rudder

The rudder stock is the part, a rod or a tube, that extends down into the rudder blade at the bottom end and at the top end has either a tiller or a quadrant whose purpose is to impart rotation to the stock so in turn it may impart rotation to the blade.

The stock runs down through a tube – the “rudder tube”, or in more old-fashinged language from bigger ships, the “rudder well”. At the top and bottom of the well there are bearings, in the old days of babbitt-metal, a special alloy used for such bearings as the ones on the crankshafts of engines (“krumtap” in Danish, so I assume also in Swedish). These bearings required frequent greasing, and that is why you have a “fedtkop” or grease cup. This device should be mounted directly where the bearings are and communicate with the bearing surfaces via a small hole right through the bearing, so that every day or two you can give them a quarter turn to force a little fresh grease onto the bearing surfaces. If the grease cup is mounted so that it communicates with the hollow between the tube and the stock (and not directly with the bearing surfaces), whatever amount of grease you inject will just fill the tube and will not lubricate the bearings as required. You should probably give thought to whether the builders of the Najads know that :-)!

These days the bearings are usually “grease-less” because they are made from low friction nylon. However, they do wear, and when the bottom one wears – which it will do because it is the one that has to cope with all the vibrating, shaking motion the waterflow over the rudder develops, it will let water into the tube. What you saw when your grease cup was leaking was this water coming out through the cap on the cup because it hadn't been kept full of grease, and there was no grease on the surfaces of the bottom bearing to compensate for the wear. Don't feel too bad about that. You would not be the first man not to have been taught that the cup needs to be replenished every week or two :-)!


Quote: “We think the problem started somewhere in the middle of the Atlantic passage some months ago. The grease-cup started to leak. Also the parts of the rudder which are inside the boat and under our beds - started to make scratches on some wood.”

The reason that the furniture, presumably the underside of the bunk-board in your aft cabin, has been scratched is that the tiller or quadrant has been able to wobble up and down because the bottom bearing in your rudder well had worn out. That is also the reason for the exceptional friction you have felt. When you remove the rudder stock from the rudder well, by removing the tiller/quadrant from the head of the stock so it can drop out of the hull, now while you are on the hard, you can replace the bottom bearing in the well. When that has been done the other problems will automatically be rectified.

You need, however, to accept that what is said in the article on electrolysis you cite is an ongoing problem for all of us, and every so often you have to repair electrolytic damage. You need to be vigilant ALL the time that it doesn't set in. I have a hunch that you started to feel the “problems” in mid-Atlantic, even though they had begun long before, because under the gentler conditions of skærgården the wear had not yet shown itself, even though it was there.

All the best

TrentePieds

[Segelplaner]

Thanks for great answer and great article. I wonder why the rudder system seems so badly documented in general? Yes, the sailing we do now around the world is a totally different cup of tea, compared to the weekend sailing in Stockholm archipelago's bracksih waters (Skärgården).

I have sent an even more detailed problem description to the Najad and also Hallberg Rassy experts in Sweden. Also created a Youtube video were you probably can hear strange sounds (I think): Najad rudder problem description video

Jonas

[Segelplaner]

Updated problem description video and removed previous one. Added a test that I guess shows that the problem is something with bearings.

Jonas

[TrentePieds]

Hej på dig :-)!

Quote: " I wonder why the rudder system seems so badly documented in general?"

No offense meant: It's because EVERYBODY knows stuff like that ;-). Well, not really - it usta be that everybody knew. But that was back in King Arthur's time when I was young and still a "DP" - a "Danish Person" :-)

And yes, those noises are "interesting"! But you also say that the rudder tube has twisted 90º in the hull and that that is what broke off the grease cup??? Did you have an unusual amount of water in your bilge? Did your bilgepump start up frequently?

It is not obvious what material the rudder tube is made from, but in a yacht of this caliber it would probably be one of the corrosion-resistant grades of aluminium or, just possibly, stainess steel. Whatever it is made from, the tube MUST be correctly repaired if it is loose. Else you are likely to sink in some unpleasant place!

In order to know the best approach to a repair, we need to know how the tube was originally fastened to the hull structure and what provision was made to resist the tube coming loose in its mounts and rotating in relation to the surrounding hull structure.

The clunking is NOT related to the rudder position, apparently. It sounds like it occurs at a random few degrees of rotation of the stock. I take it that when you recorded the sounds, you had the bunk-board up in order to make the YT clip of the quadrant?

At 0:24 in the clip, where you look straight down onto the clamp around the stock, it appears that the clamp has rotated about 90º in relation to the stock. In the clamping jaw (on the left) there is what appears to be a keyway. Similarly in the stock - pointing up in the picture - there is a keyway. I assume therefore that the "key" ("medbringer" in Danish) has come out. The clamping pressure is NOT ever enough to maintain alignment without the key being in place!

It is possible, in light of that, but not likely in light of the video, that the clunking you hear is the sound of the clamp slipping on the stock and the sound being magnified by the structure of the hull that would act like the soundboard in a musical instrument.

The key is just a square piece of metal a few inches long. The stock is S/S so go to an automotive supply house and get a piece of key stock to fit the way -possibly 1/4 x 1/4 inch, but measure it exactly.

Another posssibility for the clunking is that the tube being loose in the hull tries to turn with the stock, but gets only sofar before some tension builds up and causes it to spring back with a clunk.

Also at this point in the clip it appears that the upper end of the tube is fitted with a "stuffing box". In the old days stuffing boxes that were not constantly immersed in water would need lubricating occasionally. If you let them "run dry" they would no longer be water/grease tight.

Yet another possibility judging by the noise at 1:30 in the clip, is that a the cable/wire between steering pedestal and quadrant may have jumped a sheave. You need to inspect the whole wire run both port and starboard. If a sheave isn't turning freely, the whole block may move on its spring mount and then spring back with a clunk. Because this problem is so easy to fix when it occurs, it is the first thing I would investigate.

If I were in your boat (ahem :-)!) I'd drop the rudder off the boat, have a really good investigate and then reassemble with new parts as required. To drop the rudder you have to pull the bearing cap where the bottom of the stock is mounted to the skeg. The bolts, you will find, will have "internal hex" kerfs, also known as "Allen heads". They may even be "TorX" heads. Both of these type of kerfs will require a specific key (Driver, "nøgle") and you will need either a pneumatic driver or an electic "impact driver" to break the bolts loose in their threads. Approach with some discernment. If you "torque off" the head of one of these you'll have the devil's own time removing the broken-off shank and threaded part from the tap hole in the skeg. Remember also that the boat needs to sit high enuff that the top of the stock will clear the bottom of the boat. If it doesn't, you'll have the devil's own time jiggling the stock back into the tube :-)!

So there, that should keep you busy for a day or two :-)!

You could do other members of our forum an immense service if you'd come back to us and let us know what you find and how you repaired it!

Held og lykke :-)!

TrentePieds

[TrentePieds]

Just saw your second, updated video. It is clear that you bottom bearing, the one on the skeg, is shot. When you pull the cap off, you should find that there are two replaceable bearing "shells" within. Clean up the stock with wet'n'dry (water proof) abrasive paper, give the stock a light smear of bearing grease, fit new shells and assemble again. On this design of rudder, you should really pull the cap, clean and re-grease every time you are on the hard.

But all in all I think you have several problems, the symptoms of one masking the symptoms of the others. Such a state of affairs is really quite common, so just be systematic and go through the whole assembly one thing at a time.

TP

[Segelplaner]

Thanks, the learning curve of all info you gave, is linear from like 0% up to some 65%.
Feel much more confident what is needed todo. Carefully finish each step ahead fully focused. I will document and make a complete video and blogg from investigation to finish of this rudder problem. Showing before and after with tests.

Jonas

[Segelplaner]

I found this step-by-step guide "Howto remove rudder" from Hallberg-Rassy.

Removal and Refitting of Rudder Simmer Seals and Upper Bearings – HR 36, 39, 42F


Absolutely recommended that the boat is out of the water for these jobs.

1. Secure the rudder stock – screw a M10 eyebolt into the top end of rudder stock, attach a turnbuckle/winch arrangement to the eyebolt and support.

2. Secure the Rudder in position with a support under the Rudder.

3. Unbolt and remove the steering cables.

4. Unbolt and remove the steering quadrant and quadrant key.

5. Unbolt and remove the pilot-drive arm.

6. Mark the position and release the (62-604080) Rudder Locking Ring Bronze, allowing both the Rudder Locking Ring and (10414634) Rudder Upper Bearing 7210 to be lowered.

7. Mark the radial position, unbolt and remove the (xxx) Rudder Bearing Housing Upper. Remove both (10414634) Rudder Upper Bearing 7210 and (62-604080) Rudder Locking Ring Bronze.

8. Mark the radial position and release the (62-604075) Rudder Locking Ring Bronze.

9. Gently lower the rudder (maximum.15mm) resting it on (10414632) Rudder Skeg Bearing and also support the rudder against the ground (as already mention in above position No. 2.

10. Undo the lifting gear and remove (62-604075) Rudder Locking Ring and (10414635) Rudder Lower Bearing 51210.

11. Pull out the old simmer seals. If difficult, screwing down a few screws into the seals to help when pulling up can help, especially for the lower one. New (1312) Rudder Seals can be installed in a few different ways. But always with great care. Slots in the Rudder Shaft for Steering Gear Key and Autopilot Key can have sharp edges and damage the new Rudder Seals in the process. Clean the Rudder Shaft. Check the Rudder Shaft for any sharp edges. Wrap a paper tight around the top of the Rudder Shaft. Pull both new (1312) Rudder Seals over the paper, and then move the paper down on the Rudder Shaft with the new (1312) Rudder Seals.

If this does not work for you, grease the rudder shaft well and carefully pull down the new (1312) Rudder Seals over the Rudder Shaft. Make certain there are no burrs or sharp edges before sliding the new seals down the Rudder Shaft.

Please Note : Both seals must be fitted in the same direction, flat side facing up, open side facing down. Make sure (1312) Rudder Seals are well greased when installed. Also grease both (10414632) Rudder Upper Bearing 7210 and (10414635) Rudder Lower Bearing 51210 well when re-installing.

Make sure the Drain Hole (Leakage indicator hole) is clean and that one Seal ring is positioned below the drain hole and one Seal Ring is positioned above the drain hole.

When water comes out the drain hole, this is the indication that it is time to charge the Seal Rings.The Upper Rings is the back-up seal. For a short period of time, you can block the drain hole, before time is given to change the Seal rings, but make sure not to wait to long, as when water penetrating the upper Seal Ring, seawater will then also enter the Rudder Lower Bearing, and then other problems will also soon occer.

12. Reverse the above steps to rebuild the rudder assembly.

[TrentePieds]

Jonas:

Judging from your video I would think that the detailed construction of your rudder assembly is not QUITE like what HR describes, but the HR "manual" is still useful as a means of getting an overview of what you have to do.

Once you have that overview, and you feel comfortable with tackling the task at all, just proceed very carefully. If I were doing it, I would rely on my drafting skills to make careful sketches, drawn to scale and dimensioned for every individual bit of the assembly. To determine the dimensions of many of the smaller parts I would use a vernier caliper (skydelære) because a ruler, let alone a measuring tape, is far from accurate enuff for that purpose. Make note also of the specification of any screws, bots and nuts you find. Copious, succinct notes about your procedure as you disassemble will also prove useful.

It may take you an extra day to disassemble when you do that, but the likelihood is that having those notes and drawings (and having made the intellectual investment in making them), will save you more time than that and a lot of worry and aggravation when you do the re-assembly :-)!

I obviously cannot know the weight of the assembly for sure, but you will find that it will weigh about the same as a well-grown woman. Unless you are a regular gorilla you will not be able to support the weight of it with one hand, so it is ABSOLUTELY essential for safety's sake that the assembly be suspended from ABOVE as you begin to drop it. HR talks about installing an eyebolt in the top end of the stock. I don't see a tap hole in the top end of your stock to receive an eyebolt, but there may be one. Else there are other ways of doing it. Supporting from below is not good enuff. I had a friend, years ago, who wasn't careful enuff about that. As the top of the stock cleared came out of the bottom bearing in the hull, he couldn't hold the assembly as it toppled. It fell on him and broke his shinbone in two places. He was ten months in a cast - so do be careful!!

TP