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Old 27-10-2013, 19:14   #241
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Re: Rudder nightmare at sea

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Originally Posted by robert sailor View Post
I disagree, I think spade rudders are the most effective rudder you can have in all conditions however if using a boat for continuous offshore use they need to be built properly/overbuilt...which means they probably shouldn't be built by low cost production boat builders. Its not the design its the quality of production.


Great until they break away

I never worried about my skeg mounter rudder falling off my old Hunter 30. John Cherubini got the design right the first time!
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Old 27-10-2013, 19:44   #242
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Re: Rudder nightmare at sea

Here are a couple of suggestions for diving: go down first with a scraper and remove the barnacles. Before going overboard, prepare everything for a thorough shower immediately after finishing the dive.
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Old 27-10-2013, 21:01   #243
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Re: Rudder nightmare at sea

I hope you get it sorted mate, to what the rudder originally should have been. I can't help myself but I do note my rudders are held on by bit of string
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Old 27-10-2013, 21:18   #244
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Re: Rudder nightmare at sea

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Thanks, I hope we will all get some mileage out of this thread. The bottom bearing is situated within the hull rudder housing. If there was a backing into something previously that caused hairline damage not noticeable with the naked eye, it would likely have caused such damage at the point where it snapped off, ie, just as it exits into the water.
I'm no expert but I have seen failures like this in other applications of similar design which appeared to be caused by impact. Later when the structure failed their was evidence of the prior impact. In my opinion the design in the pictures was caused not so much because of materials used but because the steel bearing surface was not large enough to properly support the structure under impact loading. My question is: Could this failure happen without impact damage from normal use over time? B should have taken this into consideration so they should have research to answer my question.
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Old 28-10-2013, 05:01   #245
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I have read a few replies suggesting that this is an example of what production builders have to do to to keep costs down.
Yes, I know many new boats are sold to impress with interiors above all, but there are several fundamentals you have to be able to count on:

1. Keep steerage. Really, they can't spend 500-1000 more on materials and QC for a well built rudder post and rudder?
2. Keep water out. How much more are high quality through hulls and seacocks, once they are being installed?
3. Keep the boat upright. Shoddy bolt on keel installations and reinforcements, while less common, can be engineered right from the beginning?

1 and 2 above would add at most 2K per boat in production costs. # 3 probably would cost 5K at most to reinforce keel loading area and add more keel bolt, for those boats that suffer catastrophic grounding damage. If you are paying 200-300K for a new production cruiser, would you pay 5-7K more for peace of mind in this area?

On any case, yes, this rudder sounds like it fell off due to prior grounding damage. My opinion is that thick walled tube or solid post allows visual evidence of damage and would be preferable to sudden failure.


Good luck to OP- truly an ordeal
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Old 28-10-2013, 08:35   #246
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Originally Posted by malbert73 View Post
I have read a few replies suggesting that this is an example of what production builders have to do to to keep costs down.
Yes, I know many new boats are sold to impress with interiors above all, but there are several fundamentals you have to be able to count on:

1. Keep steerage. Really, they can't spend 500-1000 more on materials and QC for a well built rudder post and rudder?
2. Keep water out. How much more are high quality through hulls and seacocks, once they are being installed?
3. Keep the boat upright. Shoddy bolt on keel installations and reinforcements, while less common, can be engineered right from the beginning?

1 and 2 above would add at most 2K per boat in production costs. # 3 probably would cost 5K at most to reinforce keel loading area and add more keel bolt, for those boats that suffer catastrophic grounding damage. If you are paying 200-300K for a new production cruiser, would you pay 5-7K more for peace of mind in this area?

On any case, yes, this rudder sounds like it fell off due to prior grounding damage. My opinion is that thick walled tube or solid post allows visual evidence of damage and would be preferable to sudden failure.

Good luck to OP- truly an ordeal
Yes but track the actual numbers of 1,2,3 that actually fail ( leaving aside damage ) its in the noise compared to the quantities built. On that basis 1,2 or 3 is engineered to met the requirements despite what " old salts " say

The proof of the pudding is in the eating

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Old 28-10-2013, 12:53   #247
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Re: Rudder nightmare at sea

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Yes but track the actual numbers of 1,2,3 that actually fail ( leaving aside damage ) its in the noise compared to the quantities built. On that basis 1,2 or 3 is engineered to met the requirements despite what " old salts " say

The proof of the pudding is in the eating

Dave

That may be from a statistics perspective, but I imagine the OP would disagree. Add dismasting to my listed 1-3 above, and I think any relatively unprovoked failure is unacceptable given the consequences.

When Toyota had their "accelerator crisis" a few years ago, much was made of this, and recalls were issued. The number affected was extremely low compared to actual numbers of Toyotas driven every day, but the consequences were so dire that this was addressed and fixed for future. What if they had said: only a few people crashed out of the millions driving the car, so we'll let the defect ride....
2009

Perhaps poor analogy, but if better build quality and process will keep the rudder on, keel attached, water out, and rig up in all reasonable conditions, then why wouldn't that be done at the factory given the possible consequences? Rhetorical question- it's because the current market of new production boat buyers doesn't ask for this. They want nicely appointed 3 cabin interiors with hot tubs under queen berths, but don't ask exactly what's under the hood. A reasonable choice, but builders are putting cadillac interiors on chevy chasses.

We've established from pictures that the rudder post that snapped is of shoddy quality. Of all places to go shoddy with build quality?
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Old 28-10-2013, 13:11   #248
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Originally Posted by malbert73 View Post


We've established from pictures that the rudder post that snapped is of shoddy quality. Of all places to go shoddy with build quality?

I don't see where that's established at all , short of a proper engineering analysis , I see no such conclusion , nor has the possibility of pre existing damage been ruled out.

Beneteau 50 series is one of their most popular and rugged boats, the rudder is made by a very experienced company, I'd hold off on the posse just a while....

Dave
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Old 28-10-2013, 13:30   #249
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Re: Rudder nightmare at sea

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Originally Posted by goboatingnow View Post
I don't see where that's established at all , short of a proper engineering analysis , I see no such conclusion , nor has the possibility of pre existing damage been ruled out.

Beneteau 50 series is one of their most popular and rugged boats, the rudder is made by a very experienced company, I'd hold off on the posse just a while....

Dave
i have to agree,a 130mm shaft is extremly strong,and without a doubt the previous damage that the PO and OP knew about definitly contributed to the failure.

fiberglass and carbon is very resistant to bending loads,but shock loads are a completly different scenario.
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Old 28-10-2013, 16:14   #250
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Re: Rudder nightmare at sea

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Originally Posted by malbert73 View Post
That may be from a statistics perspective, but I imagine the OP would disagree. Add dismasting to my listed 1-3 above, and I think any relatively unprovoked failure is unacceptable given the consequences.

When Toyota had their "accelerator crisis" a few years ago, much was made of this, and recalls were issued. The number affected was extremely low compared to actual numbers of Toyotas driven every day, but the consequences were so dire that this was addressed and fixed for future. What if they had said: only a few people crashed out of the millions driving the car, so we'll let the defect ride....
2009

Perhaps poor analogy, but if better build quality and process will keep the rudder on, keel attached, water out, and rig up in all reasonable conditions, then why wouldn't that be done at the factory given the possible consequences? Rhetorical question- it's because the current market of new production boat buyers doesn't ask for this. They want nicely appointed 3 cabin interiors with hot tubs under queen berths, but don't ask exactly what's under the hood. A reasonable choice, but builders are putting cadillac interiors on chevy chasses.

We've established from pictures that the rudder post that snapped is of shoddy quality. Of all places to go shoddy with build quality?
there is a difference between Toyota, or any car manufacturer and boats. I suspect some of the missing yachts out there may be due to failures of this type so the noise you mention could in actually be much higher.
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Old 28-10-2013, 16:17   #251
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there is a difference between Toyota, or any car manufacturer and boats. I suspect some of the missing yachts out there may be due to failures of this type so the noise you mention could in actually be much higher.
Given that number of missing yachts each year is tiny, I doubt it.

Dave
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Old 28-10-2013, 19:09   #252
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Originally Posted by goboatingnow View Post

I don't see where that's established at all , short of a proper engineering analysis , I see no such conclusion , nor has the possibility of pre existing damage been ruled out.

Beneteau 50 series is one of their most popular and rugged boats, the rudder is made by a very experienced company, I'd hold off on the posse just a while....

Dave
That may be- but if you read all the posts, look at minaret's posts where he references the foam core and resin rich layup. Yes, not an engineering analysis. Defend all you want- I just think something as important as the rudder could be better engineered in many newer model production boats.
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Old 28-10-2013, 20:47   #253
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Re: Rudder nightmare at sea

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Originally Posted by malbert73 View Post
That may be- but if you read all the posts, look at minaret's posts where he references the foam core and resin rich layup. Yes, not an engineering analysis. Defend all you want- I just think something as important as the rudder could be better engineered in many newer model production boats.



There's not necessarily anything wrong with the core for this, and I'd like to emphasize that a rich layup is just a guess based on the few pics available. It would be easy to send a bit to a lab to find out for sure though.

Fiberglass Engineering Mechanics

I'm sure the OP doesn't need yet another expense right now though.

Even with a rich layup, a post this size would be immensely strong and I agree previous damage is likely. But a rich laminate is also much more brittle and more likely to delaminate and fail when repeatedly flexed to near its load limits. Resin ratio is key for flexural strength.
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Old 29-10-2013, 09:31   #254
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i have to agree,a 130mm shaft is extremly strong,and without a doubt the previous damage that the PO and OP knew about definitly contributed to the failure.

fiberglass and carbon is very resistant to bending loads,but shock loads are a completly different scenario.
There are fundamental differences between strength and toughness.

The ability to support a load is dependent on material strength and the ability to absorb energy is determined by toughness both of which are based on statistically derived material properties. The design will determine what actual values are appropriate and the will always be lower than the material specs due to stress risers etc.

In each individual case the durability of a given rudder is dependent on the loadings it is subjected to. Impacts, the design and defects will reduce its life as per miners law. If you know the actual loadings then life prediction can be very accurate.

In this case we know very little other than a catastrophic failure occurred.
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Old 29-10-2013, 10:19   #255
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Re: Rudder nightmare at sea

Taking the position that out of thousands of boats built only a few dozen have rudder failures due to under building or poor quality control is not acceptable to many people. Some of these boats had prior damage and those boats can't be criticized but many had no prior damage and just failed. Its just getting more and more common.
If you were building aircraft and told a customer that only 2-3% of the aircraft you were building would have a rudder failure absolutely no one would buy from you. If the airline told customers that 99 out a hundred flights would arrive safely no one would buy a ticket from them.
Moody built a boat in the late 70's early eighties that lost a rudder/skeg during an offshore trip and the resulting lawsuit did a great deal of damage to their otherwise good reputation built over many years. These days it seems that its acceptable to lose a certain percentage of rudders on boats, after all they weren't expensive cruisers so what would you expect? I think people do more due diligence when buying a flat screen TV than purchasing a sailboat.
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