Arcona 460 sinks

[geem]

From the OCC Facebook page
S/V IdaLina, an Arcona 460, sank earlier this week some 300 miles east of the Marquesas. IdaLina was the home of two Swedish OCC Members, Ingmar Ravudd and Katarina Bääth.

In light conditions the solid aluminium rudder stock snapped below the quadrant and then the lower section gouged a 15 cm hole in the hull. Despite best efforts, IdaLina sank rapidly and the owners witnessed and recorded her going down from their liferaft.

Fortunately, two other Swedish OCC boats were nearby and both quickly responded. S/V Pacific Wind arrived first and rescued Ingmar and Tina from their liferaft. S/V Yaghan diverted to attend with their high capacity pump but were too late to save the boat.

 

[Roberto]

 

[vyv_cox]

Very unfortunate for them. Aluminium remains ductile down to very low temperatures, so if it snaps the cause is very likely to be fatigue. Owners of similar boats would be well advised to inspect for cracks

Edit: have now seen the video. Fatigue looks likely paused at the fracture face.

 

[fredrussell]

Heartbreaking. Glad they’re ok.

 

[rotrax]

Perhaps similar to the Hanse solid aluminium rudder stock that snapped, sinking the boat.

IIRC, some compromises had been made installing the autopilot arm.

Very sad. Thankfully the owners were saved. At least boats can be replaced, lives cant.

 

[Tradewinds]

If you follow cat greatcircle on YT in their newish Outremer55 catamaran there are issues with their alu stock rudders. Apparently the blades were built oversize which has caused terminal fracturing of the stock due to fatigue . To be fair, Outremer have been very proactive and are replacing all the affected rudders with those of the correct spec. These boats are completing a rtw so have many miles under their keels at high average speeds.

 

[Minerva]

Blimey. Thank goodness for modern comms to summons help and coordinate rescue.

Can't imagine what they must be feeling now.

 

[Grace/Arcona-460]

Very unfortunate for them. Aluminium remains ductile down to very low temperatures, so if it snaps the cause is very likely to be fatigue. Owners of similar boats would be well advised to inspect for cracks

Edit: have now seen the video. Fatigue looks likely paused at the fracture face.

Greetings! New forum membrer here. It is heart-breaking to read what happened to IdaLina and her crew - we had been following their progress on Instagram and were shocked to read the final message from IdaLina. Incredibly grateful that only property was lost!

Now, we happen to own a sister ship - the Arcona 460 Grace. Grace has already crossed the Atlantic twice, so probably has equal or even more miles behind her than IdaLina. Obviously we will inspect the rudder stock very carefully. My question is then what?

If we can’t detect any visual anomaly, can we feel safe? For how long? Does anyone here have a sense for how quickly a weakening from metal fatigue happens? I hope the manufacturer, Arcona Yachts, will issue some kind of statement when their investigation concludes, but I have no doubt that that will take some time. What do we do in the meantime? The sailing season is quickly approaching, and we have extensive plans for the upcoming several months… Any advice and insight greatly appreciated!

Thanks,

Anders

 

[Neeves]

I would formally contact Arcona and ask them the questions you raise here. They have a problem, the problem is well documented. They have a moral and legal responsibility that your safety is one of their top concerns 'Duty of care'. You too know of the issues, if you think you have more sea miles than Idalina then you would be wise to forget extensive plans - until you hear from Arcona. Knowing the issues - you too have a duty of care to your crew.

In case of an accident your insurer will advise you that you knew of the problems, your post here admits same, and should not have actioned extensive plans.

All very disappointing, but just my humble suggestion.

We have metallurgical expertise in this forum - but it might not stand up (no disrespect at all to our resident metallurgist(s) when your yacht sinks and you are looking at an insurance claim.

Contact Arcona on Monday. It looks as if they need to re-engineer the rudder stock - that will take time.

Jonathan

edit, having seen Roberto's post, carbon fibre might be an option. I would be waiting for Arcona's informed replacement and then make suggestions - specifically looking at how they justify their suggestions (and I'm just guessing)

 

[Roberto]

Any advice and insight greatly appreciated

Quick-ish fit, I'd ask for a replacement rudder with a stainless steel shaft; an identical size might probably be overkill but also might not.

 

[vyv_cox]

Greetings! New forum membrer here. It is heart-breaking to read what happened to IdaLina and her crew - we had been following their progress on Instagram and were shocked to read the final message from IdaLina. Incredibly grateful that only property was lost!

Now, we happen to own a sister ship - the Arcona 460 Grace. Grace has already crossed the Atlantic twice, so probably has equal or even more miles behind her than IdaLina. Obviously we will inspect the rudder stock very carefully. My question is then what?

If we can’t detect any visual anomaly, can we feel safe? For how long? Does anyone here have a sense for how quickly a weakening from metal fatigue happens? I hope the manufacturer, Arcona Yachts, will issue some kind of statement when their investigation concludes, but I have no doubt that that will take some time. What do we do in the meantime? The sailing season is quickly approaching, and we have extensive plans for the upcoming several months… Any advice and insight greatly appreciated!

Thanks,

Anders

Fatigue is not a weakening of the metal, it is a crack or cracks propagating through the metal until the remaining part has insufficient strength for the applied load. It then fails in overload.

It appears from the video that in this case the fatigue has multiple origins. It may be difficult to detect by eye but NDT will pick it up. The simplest method is dye penetrant, cheap to buy but can be difficult to interpret. There are many more sophisticated methods that require an operator. Should be easy to find someone and not too expensive.

 

[B27]

Many boats I've looked at have at least a half-bulkhead forward of the rudder stock, so the rudder leaving the boat in an untidy fashion shouldn't flood the boat?

A rudder can't be indestructible.

 

[yotter]

That was a very unfortunate incident and pleased that all were well although must have been frightened then devastated.

I am confused as to why they use a solid alloy rod, I understand that tube is stronger, having said that I believe my stock may be solid in stainless steel, it is certainly very heavy. I am very careful to keep my alloy saildrive casting free from corrosion and would feel a bit uncomfortable having an alloy rudder stock. Does anyone know the statistics for sinkings caused by rudder failure vs saildrive failure, I would be interested to know.

 

[Grace/Arcona-460]

Thank you all for your replies!

@Neeves : Very thoughtful comments. Thank you. Given unlimited time, I agree entirely. Unfortunately, life is short, so just sitting idle while others figure this out isn’t really my style. Still I don’t want to do anything irresponsible, and I certainly don’t want to endanger others.

@Roberto : I don’t think a stainless steel rudder stock is a very appealing idea as these are performance-oriented boats which is no doubt the reason the original rudder stock was aluminum. Yet, I think using a different material might be the solution. There is a newer version of this boat, the Arcona 465, which is made entirely out of carbon fiber. I will definitely look into getting a carbon fiber rudder as a replacement.

@vyv_cox : Thanks! This is the kind of info I was hoping for! I will definitely look into getting some kind of NDT examination done.

@B27 : I’ve been thinking along similar lines. We sailed through “Orca alley” two years ago sailing from southern Portugal to Northern Europe, and we will no doubt return through these waters again. There is a bulkhead just in front of the rudder and steering wheel. It is glassed to the walls of the hull, but it is not watertight. The whole area along the bottom is open, and there are a number of cables and hoses that pass through here. I don’t have access to the boat at the moment, so can’t say for sure that this is practical, but I will look very carefully into turning this into a watertight bulkhead. That would remove any issues around sinking due to damage to the rudder area, be it from metal fatigue, Orca attacks, or other calamities.

@yotter : Thanks! I don’t have any strong feelings when it comes to material choice, as long as everything is properly engineered. As we all know, sailboat design is an art of compromises and tradeoffs… I’d bet rudder failure dominates in the statistics you mention, since it is so much more prominently exposed to the environment. I too would be interested in these stats.

Thanks again! If anyone has further thoughts on this topic, I’m most interested!

Anders

 

[geem]

How d

That was a very unfortunate incident and pleased that all were well although must have been frightened then devastated.

I am confused as to why they use a solid alloy rod, I understand that tube is stronger, having said that I believe my stock may be solid in stainless steel, it is certainly very heavy. I am very careful to keep my alloy saildrive casting free from corrosion and would feel a bit uncomfortable having an alloy rudder stock. Does anyone know the statistics for sinkings caused by rudder failure vs saildrive failure, I would be interested to know.

How do you work out that a tube is stronger than rod, assuming you are talking about the same diameter?
You don't hear of saildrives sinking boats. The issues with saildrives are more associated with corrosion. Rudder lose or steering lose is far more prevalent.

 

[Grace/Arcona-460]

I should also mention that Arcona Yachts seems to be playing well here. They have made a public statement where the CEO is acknowledging the sinking, and stating that they have launched an investigation into what the cause might be.

As an Arcona owner, I certainly appreciate this!


Anders

 

[dunedin]

Do we know what type of rudders Arcona fit. Is it for example a Jefa system?
There are perhaps hundreds of thousands of Jefa rudder stocks sailing the globe quite successfully. And not sure, but think most have alloy stocks - see this comparison Rudder Stock Materials – Jefa Rudder
It may be there was a rare defect in the stock that failed. Or less likely it was not correctly sized by the designers.
But I personally wouldn’t rush to replace with a carbon stock, per post #14, as whilst carbon is unquestionably strong, it does seem to have a higher incidence of sudden failure

 

[Deleted member 478]

...
You don't hear of saildrives sinking boats

I sold the lightning burnt out wreck of Stingo to an american couple. When they hauled her out, they insisted that the lifting straps be placed about a foot astern of the lifting marks that were clearly marked. Idiots! The straps ended up under the saildrives. That "wisdom" ended up ripping the saildrives off the engine block and breaking the saildrive seal, leaving a gaping hole in each hull of several square feet... Glug, glug, glug, said the catamaran formally known as Stingo.

It took several scuba divers to place the lifting straps in the correct position and then another four hours to slowly lift (and drain) her.

Both engines and saildrives and all the electrical looms had to be replaced.

 

[Zing]

Greetings! New forum membrer here. It is heart-breaking to read what happened to IdaLina and her crew - we had been following their progress on Instagram and were shocked to read the final message from IdaLina. Incredibly grateful that only property was lost!

Now, we happen to own a sister ship - the Arcona 460 Grace. Grace has already crossed the Atlantic twice, so probably has equal or even more miles behind her than IdaLina. Obviously we will inspect the rudder stock very carefully. My question is then what?

If we can’t detect any visual anomaly, can we feel safe? For how long? Does anyone here have a sense for how quickly a weakening from metal fatigue happens? I hope the manufacturer, Arcona Yachts, will issue some kind of statement when their investigation concludes, but I have no doubt that that will take some time. What do we do in the meantime? The sailing season is quickly approaching, and we have extensive plans for the upcoming several months… Any advice and insight greatly appreciated!

Thanks,

Anders

If I were you I'd be also thinking of how to make the bulkhead forward of the rudder watertight. It is on mine and on many other boats. It should be easy to achieve this on most boats, so I find it really puzzling that firstly manufacturers design their boats with this vulnerability and secondly that boats are not routinely modified to rectify it. This is far from the first boat to sink from damage in this area.

 

[Grace/Arcona-460]

Do we know what type of rudders Arcona fit. Is it for example a Jefa system?
There are perhaps hundreds of thousands of Jefa rudder stocks sailing the globe quite successfully. And not sure, but think most have alloy stocks - see this comparison Rudder Stock Materials – Jefa Rudder
It may be there was a rare defect in the stock that failed. Or less likely it was not correctly sized by the designers.
But I personally wouldn’t rush to replace with a carbon stock, per post #14, as whilst carbon is unquestionably strong, it does seem to have a higher incidence of sudden failure

Dunedin,

You are right! The Arcona rudders are made by Jefa! Thanks for this pointer!

I found this:
https://jefa.com/ftp/old_boat_spare_parts/Arcona/Arcona_460/Arcona_460_rudder_stock.pdf

Maybe I misspoke, I didn’t mean to say I definitely will replace the rudder - I’m still in the exploration phase of this whole thing. What I meant to say was that if it turns out that my rudder shows signs of cracking or other fatigue symptoms, or if Arcona recommends replacing the rudders, it seems more appealing to me to replace it with a carbon fiber version rather than steel. A new aluminum replacement is of course also a candidate.

Thanks!

Anders