Jenneau Rudder Shaft - Failure at Sea

[NormanB]

This is almost an hour of fairly compelling (not contrived) video - so choose your moment to start watching.

The couple are now in a place of safety in a fairly protected anchorage, but the story is not over yet.

If you only have 1 minute watch from 52:45

You Tube video here:
https://youtu.be/Gz3cLRiEmzo

 

[Deleted member 36384]

Wow! Not an expert but the video image looks like a bit of rust in an old fracture. Perhaps the rust is post failure. The key thing for me, and this is not the first time I have noticed this from videos, is how difficult it is to make an emergency rudder. There is a case for having a prebuilt emergency rudder system if one is going offshore / blue water. Glad they are safe.

 

[RupertW]

Wow! Not an expert but the video image looks like a bit of rust in an old fracture. Perhaps the rust is post failure. The key thing for me, and this is not the first time I have noticed this from videos, is how difficult it is to make an emergency rudder. There is a case for having a prebuilt emergency rudder system if one is going offshore / blue water. Glad they are safe.

The idea of rudder failure is one extra factor for having independent windvane steering. The one issue I see though is that the boat may be completely unbalanced without a rudder in place.

 

[vyv_cox]

Very little doubt in my mind that this is a fatigue fracture. The underwater shots were so brief that I could not see the initiator. I have seen serious pitting of the rudder stock in a very similar boat from the same manufacturer and this would certainly increase the stress locally. I was also not sure that I could see a change of section at the fracture, another potential cause. A good reason not to have a spade rudder.

 

[Skylark]

A good watch, I admire the fortitude of the couple. Glad that they made safe haven.

A good reason not to have a spade rudder.

Given the very high number of boats with spade rudders and reflecting upon their experience, ie 7 versions in 4 days, making a functioning jury rig emergency rudder would make an interesting magazine article. Has it already been done? What is “best practice”!

 

[NormanB]

A good watch, I admire the fortitude of the couple. Glad that they made safe haven.



Given the very high number of boats with spade rudders and reflecting upon their experience, ie 7 versions in 4 days, making a functioning jury rig emergency rudder would make an interesting magazine article. Has it already been done? What is “best practice”!

I think the most assured is to have a wind vane type steering than can act as an auxiliary rudder.

The problem with a jury rig is that the forces involved especially in heavy seas calls for large scantlings, fixtures and structure - wardrobe door and a dozen 10mm bolts is not going to cut it.

So premanufacture is the way ahead and you will probably end up with something like a wind vane type steering system in terms of strength and mounting.

 

[RupertW]

I think the most assured is to have a wind vane type steering than can act as an auxiliary rudder.

The problem with a jury rig is that the forces involved especially in heavy seas calls for large scantlings, fixtures and structure - wardrobe door and a dozen 10mm bolts is not going to cut it.

So premanufacture is the way ahead and you will probably end up with something like a wind vane type steering system in terms of strength and mounting.

I agree as per my post above but I just can't get around the idea that a small wind-vane rudder would be any use to a boat with the main rudder missing, compared to it being fixed in a central position for balance. No easy way to test that either.

 

[NormanB]

I agree as per my post above but I just can't get around the idea that a small wind-vane rudder would be any use to a boat with the main rudder missing, compared to it being fixed in a central position for balance. No easy way to test that either.

It’s a good point.
The lack of a main rudder would impact more when sailing (I think) than when motoring when the prop wash will amplify the steering effect on a small rudder (I think).

Hydrodynamicists please chip in.?

 

[Deleted member 36384]

I agree as per my post above but I just can't get around the idea that a small wind-vane rudder would be any use to a boat with the main rudder missing, compared to it being fixed in a central position for balance. No easy way to test that either.

The paddle in a windvane steering system has to be designed to be an emergency rudder. This also applies to the windvane mechanism. For example, on my Monitor system, by Scanmar, they sell a rudder foil that can be fitted in place of the paddle. The kit also comes with a mini frame mechanism to both disable the servo tilt mechanism and transmit the forces into a stronger part of the tube of the frame. Other windvanes manufacturers may have different solutions.

 

[mainsail1]

I was amazed at the small diameter of the rudder stock on what is a fairly large boat with large forces on the rudder.
I agree with Vyv Cox that a spade rudder is not a good idea for long distance sailing in any event.

 

[Kelpie]

There's been a bit of discussion for and against spade rudders on the forum before.
Incidents like this one strengthen my own feeling that I don't want one.
But there is the argument that a weak skeg is actually putting your boat at more risk than a spade- if you hit something, you could tear a hole in the bottom of the hull as the skeg breaks off.

Or you could copy what Noelex did building his Bestavaer, and use a spade rudder with a 130mm rudder stock.

 

[Resolution]

I was amazed at the small diameter of the rudder stock on what is a fairly large boat with large forces on the rudder.
I agree with Vyv Cox that a spade rudder is not a good idea for long distance sailing in any event.

There is a mention on their blog of re-bushing the rudder back in 2017. (Google translation)

"STILL NOTHING RUDDER
May 23, 2017 Oskar Comments 0 Comment
Today we went up to Källviken in the evening after work to mount the helm. The new bushing was turned and ready for assembly. Once upon a time, we lubricated the heartstock and raised the rudder. Me and Ingemar lifted while Lisa was going to steer the heartstock through the bush. How we tried, we did not get it in place. None of us understood why until we measured the hole. The new bushing was 50 mm, but the rootstock is 60 mm. Just to interrupt for the evening. The new bushing will be answered. Hopefully the mats will be correct tomorrow and we can launch it instead. On Thursday we plan to sail up to Lysekil's Marina near Skalhamn. Lysekils Marina has been very helpful to us and offered us a great place."

I wonder if there had been some earlier damage?

 

[vyv_cox]

There's been a bit of discussion for and against spade rudders on the forum before.
Incidents like this one strengthen my own feeling that I don't want one.
But there is the argument that a weak skeg is actually putting your boat at more risk than a spade- if you hit something, you could tear a hole in the bottom of the hull as the skeg breaks off.

Or you could copy what Noelex did building his Bestavaer, and use a spade rudder with a 130mm rudder stock.

I suspect that an impact large enough to fracture a skeg would probably have serious effects on a spade rudder. The problem here (assuming I am correct about fatigue) is that the fracture is not the result of impact but simply due to the natural forces applied by sailing.

Size alone does not prevent fatigue, design is critical. The biggest fatigue failure I have seen was in a sub-sea latch 2 x 0.5 metres.

 

[Achosenman]

For me, what comes across loud and clear is the apparent lack of any kind of "what If" and "What would I do"? thought process for some sailors.

Losing a rudder is not unheard of, of any design. Once you exceed the designed structural strength of a system, or don't inspect and maintain it, you stand a good chance of a failure.

Drogue steering or suitable wind vane alternatives are well documented and an effective remedy for rudder loss...providing it's not so strong it rips your transom off as it departs.

 

[RupertW]

For me, what comes across loud and clear is the apparent lack of any kind of "what If" and "What would I do"? thought process for some sailors.

Losing a rudder is not unheard of, of any design. Once you exceed the designed structural strength of a system, or don't inspect and maintain it, you stand a good chance of a failure.

Drogue steering or suitable wind vane alternatives are well documented and an effective remedy for rudder loss...providing it's not so strong it rips your transom off as it departs.

I have not yet seen a drogue actually working to keep the boat more or less straight on a modern boat, and I've looked hard and found no real world examples and not even any testing of a wind vane alternative. Getting a boat to go downwind with a little bit of steering with a rudder stuck in the middle is possible and often tested but a boat with a rudder missing altogether seems to be completely unbalanced with nothing working.

I'd love to find some examples and practices that do work or have worked on a fin keel, spade (or skeg) rudder design.

 

[Roberto]

I have not yet seen a drogue actually working to keep the boat more or less straight on a modern boat, and I've looked hard and found no real world examples and not even any testing of a wind vane alternative. Getting a boat to go downwind with a little bit of steering with a rudder stuck in the middle is possible and often tested but a boat with a rudder missing altogether seems to be completely unbalanced with nothing working.

I'd love to find some examples and practices that do work or have worked on a fin keel, spade (or skeg) rudder design.

google galerider emergency steering

 

[RupertW]

google galerider emergency steering

Searches only show it working for a disabled centred rudder that is still in place. That's not the scary scenario that we need a solution for. It might perhaps work a bit without a rudder at all but that's not the experience of those who have lost their Spade rudders altogether and failed completely with drogues.

 

[Roberto]

Searches only show it working for a disabled centred rudder that is still in place. That's not the scary scenario that we need a solution for. It might perhaps work a bit without a rudder at all but that's not the experience of those who have lost their Spade rudders altogether and failed completely with drogues.

here they have removed the whole rudder, minute 1:30
Of course it does not tell much about what might happen with rougher seas

I made one myself, though I havn t found the time to test it, tbh surely woin't take my rudder off, voluntarily that is

 

[RupertW]

My bad - I will give it a proper watch, though without wind or sea (from your still) then it's just the beginning of a test.

 

[Deleted member 36384]

My bad - I will give it a proper watch, though without wind or sea (from your still) then it's just the beginning of a test.

If you go to Scanmar website you can see their emergency rudder that fits into their Monitor wind vane frame.

https://docs.wixstatic.com/ugd/d14bae_5b38a132ba1c4d75b6f0928a13d749e3.pdf
https://docs.wixstatic.com/ugd/0ceaae_01c43be18aef4d9d9935056ed4a4d204.pdf

Also from their testimonial page

"In 2003-2004 we sailed from the UK, around South America and back - a logged distance of 20.000 miles. Most of this trip was under sail and we used the Monitor self-steering for most of the time. We lost our rudder in the South Atlantic halfway between Estrecho de Magalles and Buenos Aires.
The MRUD was rigged and steered us the remaining 500 nm to Mar del Plata in Argentina. We could,
literally, have been lost without it."
​
-Andrew Wilkes