Jenneau Rudder Shaft - Failure at Sea

[capnsensible]

Its not tube, at least not on my boat, (1998 Jeanneau 45.2) its solid stainless steel. I think that the video makes the broken one look like a tube, but I don't think that it is.

Yeah. Small anecdote. Friend of mine with same boat ran onto the breakwater going into Rabat, a notorious spot. Went on to Lanzarote and got boat lifted. Rudder bent at over 30 degrees, getting it here was a ....struggle! Got it lifted and straightened in a local yard. Sailed across for a season in the Caribbean, then back to Gib. After long argument with insurers, got a complete new rudder, bearings and shaft installed in Gib on return. My wife got the whole thing organised and delivered to Sheppards Marina. That was 2009.

Looks like the couple in the vid got a dose of un luck. :ambivalence:

 

[lw395]

Its not tube, at least not on my boat, (1998 Jeanneau 45.2) its solid stainless steel. I think that the video makes the broken one look like a tube, but I don't think that it is.

Fair enough.
But the strength comes from the outer part of the shaft, so thick wall tube wouldn't be a lot easier to bend.
There are lots of older Jeanneaus about and very very few broken rudders, so perhaps not a design flaw.

 

[rogerthebodger]

Fair enough.
But the strength comes from the outer part of the shaft, so thick wall tube wouldn't be a lot easier to bend.
There are lots of older Jeanneaus about and very very few broken rudders, so perhaps not a design flaw.

That is true in torsion but not in bending for a round beam.

Also don't forget that spade rudders are in fact a cantilever so have the maximum bending moment at the bearing at the shaft emerges from the hull.

With a tube in round rube in bending you must consider the bending moment at the point of collapse of the tube wall . You don't get collapse with a solid round bar

 

[rotrax]

That is true in torsion but not in bending for a round beam.

Also don't forget that spade rudders are in fact a cantilever so have the maximum bending moment at the bearing at the shaft emerges from the hull.

With a tube in round rube in bending you must consider the bending moment at the point of collapse of the tube wall . You don't get collapse with a solid round bar

I have much experience with fairly thick wall tubes bending from my days as a motorcycle dealer. Motorcycle fork tubes were often bent in accidents, and we were frequently required to straighten mildly bent ones.

Examination would show stretching one side, compression the other. Which would you consider the point of collapse? The stretched area or the compressed area? Or perhaps both areas?

Often the compressed area was the one that caused most rejects-surface faults would appear when straightened under our big press. The stretched area would often appear normal after being pressed straight.

Severe bending obviously meant fitting new parts. Only once in over 40 years of motorcycle repair have I seen a fork tube split at the bend, after a very severe crash with a tree. The rider got clear, thankfully.

I would expect a rudder tube to be far more substantial in wall thickness than a motorcycle fork component. My own choice of vessel has a 100mm/4 inch solid S/S shaft, in very substantial bearings. It has a weed shoe at the bottom, between the end of the keel and the bottom of the rudder but this offers little support, unlike the previous model where it supported the rudder to a far greater extent.

 

[NormanB]

The couple on HILMA (rudder shaft fracture) have released a ‘routine’ YouTube video covering a prior part of their journey well before the rudder loss. They do some talking to camera at the beginning of the video and thank everyone that has been supportive (which will enable them to continue with their adventure). No real details yet on repair solutions or action. Sounds like it is all still very much at the investigation and evaluation stage.

 

[rogerthebodger]

I have much experience with fairly thick wall tubes bending from my days as a motorcycle dealer. Motorcycle fork tubes were often bent in accidents, and we were frequently required to straighten mildly bent ones.

Examination would show stretching one side, compression the other. Which would you consider the point of collapse? The stretched area or the compressed area? Or perhaps both areas?

Often the compressed area was the one that caused most rejects-surface faults would appear when straightened under our big press. The stretched area would often appear normal after being pressed straight.

Severe bending obviously meant fitting new parts. Only once in over 40 years of motorcycle repair have I seen a fork tube split at the bend, after a very severe crash with a tree. The rider got clear, thankfully.

I would expect a rudder tube to be far more substantial in wall thickness than a motorcycle fork component. My own choice of vessel has a 100mm/4 inch solid S/S shaft, in very substantial bearings. It has a weed shoe at the bottom, between the end of the keel and the bottom of the rudder but this offers little support, unlike the previous model where it supported the rudder to a far greater extent.

This is the type of collapse or buckling I and talking about.

This kind of kink cannot be bent back. If I get this kind of king I cut out and sleeve to align the ends and reweld.

I worked in the tube industry both in the making and the manulaping of tube. (bending by various methods.

Thin wall will buckle or kink much easier that thick will in my day thin wall tube was rolled and welded think wall tube was solid drawn.

Thick wall I use is schedulr tube ranging from schedule 5 to schedule 160.

https://www.pitpipe.com/pipe-schedule-chart.html

 

[jimi]

Worth pointing out that not all rudder failure is as a result of rudder loss. On my previous boat (spade rudder) the rudder failure was due to progressive failure of the tangs inside the rudder leading to a gradual loss of directional stability (long words meaning the bvgger weaved in increasingly random directions). In the case of complete failure unless the rudder aligned with water flow any emergency rudder would have to overpower the random motion of the faulty rudder. If the original rudder stayed aligned it would be much much easier and a lot could be achieved by balancing the sail plan.

 

[rotrax]

This is the type of collapse or buckling I and talking about.

This kind of kink cannot be bent back. If I get this kind of king I cut out and sleeve to align the ends and reweld.

I worked in the tube industry both in the making and the manulaping of tube. (bending by various methods.

Thin wall will buckle or kink much easier that thick will in my day thin wall tube was rolled and welded think wall tube was solid drawn.

Thick wall I use is schedulr tube ranging from schedule 5 to schedule 160.

https://www.pitpipe.com/pipe-schedule-chart.html

Those examples are pretty thin wall compared to the older style motorcycle fork tubes I used to straighten. When bent backwards as much as the ones shown they never deformed in the same way. Many fork tubes were multi internal diameter too-for weight reduction and to incorporate the internal damping mechanisms.
Trying to straighten the ones shown would be a lost cause.
I used to make one off motorcycle frames from Reynolds 531 or T45 tube, using low temperature nickel bronze welding. IIRC 531 was multi wall thickness-thicker at the ends, and was normally used for racing bicycles, supplied in a complete frame set. I once owned a 531 tube track iron from the Hearn Hill cycle racing track that was silver soldered instead of brazed at the lugs.
Reynolds thinwall tubes-and perhaps Accles and Pollock thinwall tube-was seamless.

 

[NormanB]

How any of this is relevant to the subject matter of the thread which is rudder shaft breakage on a Jenneau I just do not know.

The video (if you ever viewed it) showed very clearly a solid shaft. Now while discussion about the failure mode of that is interesting and relevant introducing thin walled tube, buckling stress and repair options on motorcycle forks and frames is just extracting the urine.

I am a motor cyclist too and love bikes BTW.

 

[Resolution]

How any of this is relevant to the subject matter of the thread which is rudder shaft breakage on a Jenneau I just do not know.

The video (if you ever viewed it) showed very clearly a solid shaft. Now while discussion about the failure mode of that is interesting and relevant introducing thin walled tube, buckling stress and repair options on motorcycle forks and frames is just extracting the urine.

Spoilsport!

 

[Achosenman]

Its not tube, at least not on my boat, (1998 Jeanneau 45.2) its solid stainless steel. I think that the video makes the broken one look like a tube, but I don't think that it is.

I've just had a look at mine. It's a 2005 Jeanneau SO 40.3. The rudder stock is solid stainless steel at 63mm in diameter.

I just don't see how something that heavy duty snaps without long term degradation at work.

 

[vyv_cox]

I've just had a look at mine. It's a 2005 Jeanneau SO 40.3. The rudder stock is solid stainless steel at 63mm in diameter.

I just don't see how something that heavy duty snaps without long term degradation at work.

I am not sure at what date the composition may have changed but current shafts on similar boats by that manufacturer are duplex stainless steel. This alloy provides greater fatigue resistance. As said earlier, size is no barrier to fatigue.

 

[Achosenman]

I am not sure at what date the composition may have changed but current shafts on similar boats by that manufacturer are duplex stainless steel. This alloy provides greater fatigue resistance. As said earlier, size is no barrier to fatigue.

The Owners of Hilma have found the cause. They had stray DC current from their compass set up corrosion in the rudder stock. Faulty wires or some such. There is a post on Jeanneau pro boards about it.

 

[vyv_cox]

The Owners of Hilma have found the cause. They had stray DC current from their compass set up corrosion in the rudder stock. Faulty wires or some such. There is a post on Jeanneau pro boards about it.

Do you have a link? Corrosion pits are a common initiator for fatigue. I only saw the fracture face briefly in the video but it looked like typical fatigue to me.

 

[Achosenman]

Do you have a link? Corrosion pits are a common initiator for fatigue. I only saw the fracture face briefly in the video but it looked like typical fatigue to me.

I’m on my iPad ATM and it’s not very friendly for getting links posted...probably just my incompetence.
Here’s a copy plus a link...I hope.

Response from the owners.

Thanks for your mail. First of all, you should not worry about your rudder. Our rudder was damaged by leakage DC current from the compass, which created corrosion in the rudder shaft. we found out after a lot of troubleshooting on board. We were unlucky in that way. We have now removed all power cables that are at risk of being damaged and that can get in contact with the steering and in the long run the rudder itself.

Read more: http://jeanneau.proboards.com/thread/7053/rudder-stock-failure-on-jso45#ixzz5dEJSVZYV

 

[Genoa]

...Showing my ignorance, but could someone describe the sort of DC leakage referred to (typically leaking to where/how?) and what sensible check could/should be made?