tudorsailor
Well-Known Member
Here is the PBO test
https://www.pbo.co.uk/seamanship/jury-steering-oh-rudder-where-art-thou-25156
TS
Jenneau Rudder Shaft - Failure at Sea
- Thread starter NormanB
- Start date
Here is the PBO test
https://www.pbo.co.uk/seamanship/jury-steering-oh-rudder-where-art-thou-25156
TS
geem
Well-Known Member
I suspect the issue is likley to be that few boats with a spade rudde just lose the rudder and stay afloat. Hit something hard enough with a spade rudder and your pivot point is the bearing. Damage this a little and you would expect a leak. Damage it a lot and you would smash out the structure around the bearing and possibly lose the rudder leaving a shaft sized hole at least.
I saw a Swan being repaired this summer after going on a reef. Lots of keel damage but the spade rudder was snapped in half. The s/s shaft only went half way down the rudder blade. I suspect this was to allow the rudder to fail in such a way that it didnt rip the shaft out of the hull. It would still give you half a rudder after a bad grounding. If you hit something higher up the rudder then the shaft bending or damaging the hull structure is more likely. Whether there was enough rudder left to steer with, I have no idea. The yard did a great job of making a new rudder
[70521]
Well-Known Member
We had an interesting incident last summer. Reversing the boat out of the berth with helm over to 20 degrees of port I found the wheel would not turn the rudder. Two crew onboard, one extremely experienced, (we can call call him A) the other a total beginner (we can call him B). A to me where is the emergency tiller, me to A cockpit locker on the shelf. B getting quite worried as he sees all the activity at the wheel as I control the turn on the throttle . A to me got a spanner there is a nut here, me to A its only finger tight. At this point heads are popping up all over the marina. Crew from a rather big Princess M Class gather some fenders. A gets emergency tiller on the stock, we now have control over the direction of travel. A wave to all and sundry and off to go to sea to sort out the wheel. In moving stuff in the cockpit locker the valve on the hydraulic system had been switched to the override position.
The tiller worked well because it was at hand, ready for instant use and is the same size as if the boat was built as a tiller steered one. I now check that I have propulsion and can turn the rudder before casting off.
kof
Well-Known Member
Only valid if you collide with something and even then the chances of it impacting both are much reduced. In the case of this boat, it looks like fatigue and not a collision, so a dual rudder setup would have worked great.
RupertW
Well-Known Member
Have you any evidence for that? I've seen a few examples each year about rudders delaminating or coming off but nothing about boats sinking as a result. I may well be wrong on that but haven't come across examples.
AndrewB
Well-Known Member
Using a wind-vane as an emergency rudder .... Try it before you rely on it. I tested first lashing the real rudder central. It worked quite well in calm water under motor. In an Atlantic swell, it was useless, either sailing or motoring. Can't imagine it would have been any better had the rudder gone altogether, or worse still bent to one side.
My solution (when blue-water sailing) was to carry an aluminium ladder which served several purposes as well as a ladder, e.g. as a fender board, but also as an emergency rudder. One cabin door had holes pre-drilled so that it could be dismounted and lashed to the lower half of the ladder as a blade. The upper half of the ladder was shackled loosely to the eyes on the stern that normally held the wind vane. A piece of steel tubing was clamped with U-bolts to the top rung of the ladder, for use as a tiller. This at least worked when tested in rough conditions, even with the real rudder lashed a little off-centre. It was a good deal sturdier than the sweep shown in the PBO article, though how long it would have lasted I would not like to say.
P.S. My yacht was longish keeled and so directionally fairly stable. It might be different with a fin-keeled yacht.
My solution (when blue-water sailing) was to carry an aluminium ladder which served several purposes as well as a ladder, e.g. as a fender board, but also as an emergency rudder. One cabin door had holes pre-drilled so that it could be dismounted and lashed to the lower half of the ladder as a blade. The upper half of the ladder was shackled loosely to the eyes on the stern that normally held the wind vane. A piece of steel tubing was clamped with U-bolts to the top rung of the ladder, for use as a tiller. This at least worked when tested in rough conditions, even with the real rudder lashed a little off-centre. It was a good deal sturdier than the sweep shown in the PBO article, though how long it would have lasted I would not like to say.
P.S. My yacht was longish keeled and so directionally fairly stable. It might be different with a fin-keeled yacht.
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geem
Well-Known Member
Achosenman
Well-Known Member
I didn't use specifics for the failure. It is unhelpful when wading through the data. It's too easy to become bogged down in the minutiae.
I do think you might need more than one method. A jammed rudder might need a drogue to help offset the turning force from the main rudder to allow a hydro-vane to be effective. Every situation will be different. Every type of rudder is at risk from failure, especially since some don't seem to get regular maintenance until a problem becomes apparent.
I believe that thinking about failures and practicing a fix is good seamanship, not to mention fun on a lazy day as you bimble about with the Admiral.
AndrewB
Well-Known Member
Rudderless boats in mid ocean frequently get abandoned, which comes to much the same thing since they are usually subsequently lost, except of course the crew have time to organise getting picked up.
In one remarkable case from the ARC of 2007, two yachts, a Bavaria 35 'Arnolf' and a Grand Soleil 39 'Stella di Mare' were both abandoned mid-Atlantic as a result of rudder loss. These were separate incidents hundreds of miles apart. Several months later both yachts showed up in Anguilla, three days apart, each having travelled over 1000 miles without a crew (photo below from 'Anguilla News').
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RupertW
Well-Known Member
And that is exactly opposite to the assertion that losing a spade rudder is likely lead to a sinking. Abandoning ship I can see as there is so little chance of the normal alternative methods of steering working but you'd have time to prepare.
kof
Well-Known Member
Ok and I agree that multiple methods to deal with it are needed and above all, practice them on a nice day. You need to know how it will behave and whats works/doesn't work before you get into trouble.
My next boat will have twin rudders (performance and safety) but I'm also looking at building a carbon emergency rudder in case I lose both. Hope never to have to use it in anger but I will sleep better knowing it's there.
My next boat will have twin rudders (performance and safety) but I'm also looking at building a carbon emergency rudder in case I lose both. Hope never to have to use it in anger but I will sleep better knowing it's there.
Silver_Surfer
New Member
if i read this correctly the inside diameter of the rudder bearing is 50mm? if i'm right then my 37 baltic has a 76mm-3" that seems rather small for a 45ft boat. now i wonder, what is the formula for a proper shaft? diameter to LOA? LWL? displacement?
[2068]
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I thought they were doing pretty well until 43:50, which looked like an unsafe version of utter stupidity to me, but I am guessing that fatigue had taken its toll by this point.
Even his partner could see what was going to happen when the tow line came under tension, and he's still got hands and feet in the area!
Even his partner could see what was going to happen when the tow line came under tension, and he's still got hands and feet in the area!
Norman_E
Well-Known Member
It is probably the case that rudder shaft diameters are a bit of a guess, largely drivem by knowing what has worked in the past rather than by any solid science. I read what was said to mean that the bearing had been made 50mm bore and the shaft would not go in because it was 60mm. My own older Jeanneau Sun Oddessey 45.2 has a solid stainless shaft which is 2.5 inches diameter if I remember correctly from when I had the upper bearing rebuilt. 2.5 inches is 63.5mm. In my opinion the replacement model 45 is a less well specified boat so a reduction in rudder stock size does not surprise me. Vyv Cox can correct me if I am wrong but I think that torsional stiffness increases or decreases by the cube (or is it the 4th power?) of the diameter, and resistance to bending by the square so even a small reduction in diameter can have a big effect.
geem
Well-Known Member
That Sun Oddessy rudder shaft doesnt sound that strong. My Trintella 44 has a full length skeg, three bearing rudder. The shaft diameter at the main bearing is 100mm. The rudder shaft is solid 316 s/s. It seems that mine might be a little over engineered by Mr Van de Stadt.
But I have to agree, new boats seem to get less substantially engineered. Somebody will come along and say that all that is needed but there are areas of boat design that I want over engineered. Those being rudder, keel and chainplates. Why would you want those items just strong enough? Over engineered sound perfect to me. Nobody has been in a storm and said ” i wish I had smaller keelbolts right now” or “I wish my rudder didnt have such a strong shaft when we went over that log” or “I wish my chainplates were smaller during that knockdown”
rogerthebodger
Well-Known Member
This is the compromise between weight and strength mainly when racing is involved.
For cruising boats weight is not so much of an issue but on any racing machine weight is.
geem
Well-Known Member
Of course. Sailing on a high performance racing machine is totally different. Carbon rudder shafts instead of s/s. A race boat I crewed on last year had a carbon rudder shaft. It snapped. The quote for a new one was $10,000. The boat is 37ft Carbon beast and very competitive. As cruisers we are looking for this kind of performance or this kind of repair bill!
lw395
Well-Known Member
2 inches of heavy gauge stainless tube should not be a weak thing.
It's not hard to work out what's strong enough.
It sounds like this was bodged after a design error, resulting in a stress raising 'feature'.
Or possibly the rudder was hit by flotsam, whale, mooring...?
It's not hard to work out what's strong enough.
It sounds like this was bodged after a design error, resulting in a stress raising 'feature'.
Or possibly the rudder was hit by flotsam, whale, mooring...?
Resolution
Well-Known Member
Rudder stocks can be very heavy items. While Resolution was being built we made a visit to the factory over in Maine, USA. They made a quiet point that they had switched from s/s to carbon fibre in order to save weight. The original s/s version (for a 42 foot yacht) was quite a job for a single person to lift, whereas the carbon fibre version could be held with one hand - just.
Now you have scared me thinking about repair costs!!
Norman_E
Well-Known Member
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.