New yachts rudder bearing failures

[geem]

True but if you want to supply bearings that are approved by Lloyds you have to carry out a rudder simulation test for 1000hours. Increasing loads every 200 hours on a simulation rig in the lab.

Highest load we tested to was final 200hours at 20Mpa or around 2900PSI. The test was designed to show wear rates of rudder shaft and bearing run dry. Our results showed no measurable wear on rudder or bearing.

I'd like to know the source of this report/information as it hasn't been picked up by the press?

Refer to post one. A guy with rudder bearings that need replacing under warranty on a new Jen 54. He volunteered the info on rate of bearing failure of other boats on the ARC. Said it was common and due to all the downwind sailing.

 

[Just_sayin']

Refer to post one. A guy with rudder bearings that need replacing under warranty on a new Jen 54. He volunteered the info on rate of bearing failure of other boats on the ARC. Said it was common and due to all the downwind sailing.

Common yet the only source is him.

 

[geem]

Have to agree , the OP has not stated any factual proof rather a hear say from one person who then goes onto to say loads of others have suffered the same fate (loads = what number) then op tells us that out of the 200+ boats that sail the ARC most are under 3 years old
now I have seen a lot of ARCs and there are plenty of Cats in there , racing boats competing for the fastest time, and the usual cruisers
so I cannot take anything seriously from an old sea dog at the bar telling their stories until there is proven fact
As JS Posted no magazine coverage , no ARC safety announcements no nothing in fact but gossip , but we all know gossip to be true that why we listen to it and write about it on these forums
Maybe Geem your are slightly biased to new boats as you have previously vocalised on many other threads

Wow, chip on shoulder maybe... i am referring to bearings on a Jen 54 that needs them replacing after crossing the pond. The owner stated there were other boats that had similar problems. I have stated the source of the information. Not a chat in a bar. From the owner of said Jen 54 with bearings worn to the point of a warranty claim. Why would the ARC issue a safety notice. Worn bearings rarely cause a rudder failure. They just tend to clonk so you know they need replacing. My point is why is this happening on new boats? It a technical question and there has been some interesting debate.

 

[vyv_cox]

The SKF design bearing calculation is based on 90% life of bearings

Basic rating life
For simplified calculations and to obtain an
approximate value of the bearing life, the so-called “handbook method” is used to calculate the basic rating life. The basic
rating life of a bearing according to ISO 281

Life 10 = (C/P) to the power of p


where
L10 = basic rating life (at 90% reliability), millions of revolutions
C = basic dynamic load rating, kN
P = equivalent dynamic bearing load, kN
p = exponent for the life equation
= 3 for ball bearings
= 10/3 for roller bearings, as used
typically in axlebox applications
The basic rating life for a specific bearing is
based on the basic dynamic load rating
according to ISO 281. The equivalent
bearing load has to be calculated based on
the bearing loads acting on the bearing via
the wheelset journal and the axlebox
housing.

Plain bushe life is based on a PV value (Bush pressure and bush surface velocity)

The PV valve is compared to the PV for the bush material obtained from the bush supplier.

I use vesconite whos bush design manual is here

https://www.vesconite.com/wp-content/uploads/2016/12/vesconite-marine-design-manaul.pdf

These ratings all refer to a rotating bearing. Oscillating bearings are a different matter altogether.

 

[FlyingGoose]

Wow, chip on shoulder maybe... i am referring to bearings on a Jen 54 that needs them replacing after crossing the pond. The owner stated there were other boats that had similar problems. I have stated the source of the information. Not a chat in a bar. From the owner of said Jen 54 with bearings worn to the point of a warranty claim. Why would the ARC issue a safety notice. Worn bearings rarely cause a rudder failure. They just tend to clonk so you know they need replacing. My point is why is this happening on new boats? It a technical question and there has been some interesting debate.

No chip I just like facts your OP statement did read like many boats had same issues and that that all those were boats under 3 years and were from Marques of so called lesser boats you words :encouragement:
I am only commenting on your words no chip , no issues , no bother just like the truth and the reality is that this is scare mongering at its best from the fellow who told you , I would suspect that he was really pissed off at this failure and perhaps in his angry state as we all tend to do voice off in large quantities to anyone listening, and the tall tale gets spun :encouragement:

 

[Just_sayin']

Since most boats on the ARC in 2018 were less than three years old, what is going on with these modern boats and rudder design? I cant imagine buying a new boat and having rudder bearings issues in such a short space of time

Since you seem determined not to answer questions posed such as lack of publicity regarding the “problem” and the general knowledge of actual participants perhaps you could cast your eye over the actual entry list and give us the benefit of your insight into the ages of the boats.

https://www.worldcruising.com/arc/arc_2018_evententries.aspx

 

[rogerthebodger]

These ratings all refer to a rotating bearing. Oscillating bearings are a different matter altogether.

Yes and oscillating and stationary bearings using ball and roller bearings are subject to damage due to single point loading especillary to alternating loading.

steering ball or rose joints do not use ball/roller bearings as the loading are oscillating bearings just like rubber bearings.

 

[dunedin]

Refer to post one. A guy with rudder bearings that need replacing under warranty on a new Jen 54. He volunteered the info on rate of bearing failure of other boats on the ARC. Said it was common and due to all the downwind sailing.

But per earlier posts, this view on recent ARC needs some evidence as not known to other ARC participants in St Lucia.
With 200 odd boats there are always multiple failures of some things - wind vanes, sails etc. Doesn’t necessarily mean any systemic issue, just a lot of wear and tear with 200 boats doing 600,000 odd sailing miles. And no evidence yet that rudder bearings were even one of the multiple issues.

 

[rotrax]

No chip I just like facts your OP statement did read like many boats had same issues and that that all those were boats under 3 years and were from Marques of so called lesser boats you words :encouragement:
I am only commenting on your words no chip , no issues , no bother just like the truth and the reality is that this is scare mongering at its best from the fellow who told you , I would suspect that he was really pissed off at this failure and perhaps in his angry state as we all tend to do voice off in large quantities to anyone listening, and the tall tale gets spun :encouragement:

WOW!

In that case, when posting on other threads, quote facts, not opinion.

Own goal here, I think!

 

[Neeves]

Sorry but I'm with the OP.

If there is a bearing issue on a, relatively new, yacht from a reputable maker and the bearing fails such that it is a warranty issue - then the issue should be aired.

I assume other yachts have the same bearings (which I further assume might be used on other yachts) - and owners might be interested as it might give them something to add to their service list - and they might have pointers as to what to look for.

Some might want to sweep it under the carpet (cannot think why) - but if I were an owner, or had the same, or similar, bearings - I would want to know.

It might be a one off - one would hope so.

Our outhaul failed, it snapped - it was stainless - I know its not life threatening - but it was very inconvenient (in SW Tasmania). I later complained to the mast builder - a standard marine industry response

"We have never heard of that before, that is terrible, we will send you a new outhaul' (dyneema not stainless) -

later it transpired the issue was common and well known to the mast builder - but the mast builder had chosen not to warn anyone.

Jonathan

 

[FlyingGoose]

WOW!

In that case, when posting on other threads, quote facts, not opinion.

Own goal here, I think!

No idea what your talking about sorry if your offended, but I dont really care and to bring other threads into it I just don't get are you a stalker I can PM you my address and you can stalk me some more