Oceanis 485 steering failure

[SimonV]

Originally Posted by MarkJ

I tried to Google marine crash pumps and came up only with forum posts but no actual products.


What product should we be looking at?

I certainly don't want a pump attached to the engine as that's likely not to be working.

12v?

Or portable engine fire type pump?

In Oz we call them TRASH PUMPS.

Sent from my GT-N7105T using Cruisers Sailing Forum mobile app

[estarzinger]

None of these pictures are of the exact model of interest (I'm still looking), but they are of similar size twin wheel/single rudder benni's. They all show very similar engineering similar to what highland described - a rudder tube that goes to about (roughly) 60cm above the static waterline, with a bearing in the bottom and top of the tube and quadrant/tillers above that and no bearing at the top of the shaft of the tube/under the deck.

Given that . . . . for the autopilot to to have caused the leak - autopilot pushing on the shaft would have had to actually crack that fiberglass tube.

It is possible, and the autopilot is pushing on the end of the tube that is less well supported. A mostly in place tube with a big crack would also be consistent with the video showing the rudder still looks stable and is not wagging all over but could have let in the sort of flooding rate we have calculated happened.

But my initial thought is that I wonder if that tube had already been damaged (from a prior grounding perhaps). That tube had to be engineered to handle the full rudder loads on a much longer lever arm than the autopilot had and should have been quite hard to crack.

Certainly this is much harder than damaging a near waterline seal and makes me a bit more thoughtful about the other sources of water ingress. . . And the autopilot failure being a symptom rather than cause.





have to say I like the long tube but would prefer the upper bearing as high as possible just under the deck. But I suppose it must be a cost effective way to build the boat.

[Polux]

Originally Posted by Denise-SJD

One rudder

Beneteau has a very strange policy in what regards rudders and not only on the Oceanis line. Boats with apparently the same type of hull, designed by the same NA have different configurations : the 35 and 38 have twin rudders, the 41 and 45 have a single one. The 48 has one, the 55 has two.

It is hard to figure that out but I guess that they are tryng to understand what the clients prefere, or if the more expensive set up of two rudders is justified. It seems that yes, since the more recent boats have two rudders, the Sense 46 included.

[MarkJ]

Originally Posted by estarzinger

Given that . . . . for the autopilot to to have caused the leak - autopilot pushing on the shaft would have had to actually crack that fiberglass tube.

It is possible, and the autopilot is pushing on the end of the tube that is less well supported. A mostly in place tube with a big crack would also be consistent with the video showing the rudder still looks stable and is not wagging all over but could have let in the sort of flooding rate we have calculated happened.

But my initial thought is that I wonder if that tube had already been damaged (from a prior grounding perhaps). That tube had to be engineered to handle the full rudder loads on a much longer lever arm than the autopilot had and should have been quite hard to crack.

Certainly this is much harder than damaging a near waterline seal and makes me a bit more thoughtful about the other sources of water ingress. . . And the autopilot failure being a symptom rather than cause.

My quadrant is above the top bearing too.

The rest of your post is pretty much what I thought in my previous post.

Previous grounding? In such a way that the rudder took some force?

That would explain the white bit at the hull joint.


Btw, being on a charter boat means you don't know the boat from diddly-squat. We can find all the spaces on our boats but would the charter company have shown the charterers the lazarette where the quadrant is? I doubt it.

[undercutter]

Originally Posted by partyanimal

My friends chartered an Oceanis 485 in the Caribbean and were sailing in the Leewards in some 500m of water with autopilot ON. Suddenly both wheels started turning from port to starboard very fast making a lot of noise. The autohelm control panel was positioned behind the starboard wheel so it was impossible for the helm to quickly disengage the auto setting. He had to move forward and carefully get his hand down between the rotating wheel and the instrument to locate the off button. Before he could do this there was a large noise and the wheels stopped. Having regained control it was apparent that they had lost steering. The next stage was to engage the emergency tiller, this was done but the yacht did not respond to the the tiller. As they were sailing with another group they were taken in tow. Shortly afterwards the saloon was filling with water, the auto bilge pump did not function, the manual bilge pump did not function and manual bailing was started. Initially a Pan-Pan was issued this was then upgraded to full Mayday. The CG arrived by helicopter but were unable to help so the crew were taken off onto another yacht in the fleet. A short time later the Oceanis sank. Has anyone experience of this type of rudder failure on an Oceanis 485 under autohelm or manual helming. My friend is adamant that no damage was inflicted on the yacht but the charter company suggested he may have hit a lobster pot. He is sure that he did not hit anything. Even so I would expect he may have got the line caught around the prop but not wrecked the rudder if a lobster pot had been struck. The rudder failure caused the boat to be lost. Any experience of this type of failure would be appreciated.

Are bilge alarms not standard equipment on all charter yachts?? Doesn't seem reasonable that a leaking shaft seal would allow such a rate of water ingress that the water level would reach up to the salon sole so quickly with the rudder still inside the rudder tube!! This is mentioned to be after they were taken in tow but???

Makes a lot more sense to me that the autopilot failure was a result of the water ingress and not the other way around and this subsequently damaged the mechanism or as someone else said the emergency tiller was just harder than expected to operate. Knowing the location of the pump and brain might give some indication of the sequence of events. As I am sure that this would have been factory installed maybe someone else knows where they are typically located.

By the sounds of this story anyone wishing to charter a vessel should give serious consideration to performing a full seatrial and survey including haul out before they leave the dock.

[neilpride]

Originally Posted by estarzinger

None of these pictures are of the exact model of interest (I'm still looking), but they are of similar size twin wheel/single rudder benni's. They all show very similar engineering similar to what highland described - a rudder tube that goes to about (roughly) 60cm above the static waterline, with a bearing in the bottom and top of the tube and quadrant/tillers above that and no bearing at the top of the shaft of the tube/under the deck.

Given that . . . . for the autopilot to to have caused the leak - autopilot pushing on the shaft would have had to actually crack that fiberglass tube.

It is possible, and the autopilot is pushing on the end of the tube that is less well supported. A mostly in place tube with a big crack would also be consistent with the video showing the rudder still looks stable and is not wagging all over but could have let in the sort of flooding rate we have calculated happened.

But my initial thought is that I wonder if that tube had already been damaged (from a prior grounding perhaps). That tube had to be engineered to handle the full rudder loads on a much longer lever arm than the autopilot had and should have been quite hard to crack.

Certainly this is much harder than damaging a near waterline seal and makes me a bit more thoughtful about the other sources of water ingress. . . And the autopilot failure being a symptom rather than cause.

Attachment 118014
Attachment 118015
Attachment 118016

have to say I like the long tube but would prefer the upper bearing as high as possible just under the deck. But I suppose it must be a cost effective way to build the boat.

I dont think this boat get water by the rudder unless it rip off the FG tube, like Blue Pearl, remember? the tube end above the waterline , no bottom seal or stufing box, they usually end the top with a rubber seal, the rudder is still there flapping one side to the other , and no deflection noted in the video,,, the white spot surrounding the plastic spacer is a concern ....

Quite a mystery!!!

[MarkJ]

Originally Posted by undercutter

By the sounds of this story anyone wishing to charter a vessel should give serious consideration to performing a full seatrial and survey including haul out before they leave the dock.

To charter a boat for a week you expect to haul it out and pay for a survey first?


Well that's an idea I have never considered.

Anyone else done a $1,000 survey and haulout for a 1 week charter?


Mark

[neilpride]

Charter companys normally have a diver in their maintenance crews , they often dive to check for damages or simple maintenance tasks, they haul out the fleet very often to, as a example every 6 months Dream yacht charters move their Multi fleet to the boatyard for antifouling and zincs, between 6 months and a year time frame.... same for monohulls,,, the problem come when they have a busy season and boats are booked like cars , is not dificult to see a Catana coming from a 2 weeks charter holydays and the next customers arriving with hours of diference and leaving next morning, ******** who dont notify to the charter company incidences with the boat put in risk the company and customers.... my 2 cents.

[estarzinger]

Originally Posted by MarkJ

My quadrant is above the top bearing too.

The rest of your post is pretty much what I thought in my previous post.

I learned something, and am perfectly willing to admit it . I did not know this tube with integrated "upper" bearing design was so common. I guess the reason is that the tube essentially automatically aligns the bearings. If you put the upper bearing in its "proper" place up as high as possible under the deck, then it is rather fussier to get it exactly aligned. .

Previous grounding? In such a way that the rudder took some force?

That would explain the white bit at the hull joint.

Yea, "something" happened to that rudder assemble - but the "white" could easily appear with just internal hardware damage letting the rudder drop a bit, also jamming it so the emergency tiller did not work . . . All caused by the autopilot going crazy . . . Without necessarily damage to the tube. . . . If the autopilot was a symptom of flooding from somewhere else.

Thst tube "should" be really strong and really hard to crack. I would want the engineering to specify that the rudder break before that tube cracked. . . . Somewhat better to have no rudder and be still floating than to have a rudder and be sinking.

To help assess whether the autopilot was cause or symptom . . . I agree with the comment/question in the post asking where the autopilot bits are typically installed and how easy would they be to short with water coming in from somewhere else. I think that would be the next question to answer. Given the described autopilot action . . . A shorted rudder reference unit signal could cause it, possibly a shorted fluxgate.

If the autopilot components are mounted so high that flooding would have had to be obvious before they shorted, and away from possible "spray shorting" (eg away from raw water pumps and deep thru hulls) then we focus on the autopilot as cause, and ask if the ram was strong enough with enough leverage to crack that tube, or if there had to be prior damage..

Btw, being on a charter boat means you don't know the boat from diddly-squat. We can find all the spaces on our boats but would the charter company have shown the charterers the lazarette where the quadrant is? I doubt it.

They did manage to find the emergency tiller, which I was surprised/impressed with.

.......

[transmitterdan]

Originally Posted by estarzinger

None of these pictures are of the exact model of interest (I'm still looking), but they are of similar size twin wheel/single rudder benni's. They all show very similar engineering similar to what highland described...

The second picture shows something that is "scary" to me. The main quadrant is connected to a lower smaller tiller arm. That arm appears to be for the rudder feedback sensor. It also performs the rudder stop function. It would seem possible for the lower much smaller part to break. That would cause loss of both rudder feedback to the AP and loss of rudder stop system. If the sunken boat model uses this same arrangement then that would be worth a bit more educated speculation IMO. Without rudder feedback an AP may oscillate stop to stop as in the OP description.

Also, here again we see a safety critical item (rudder stop) that appears to be fastened to some thin plywood. A rudder stop needs to be "unbreakable" for the safety of the boat. And if the stop should fail that failure should not compromise the rudder itself.

[MarkJ]

Here is my tube. Note the buttressing on 4 sides.
Obviously my boat is much older and a previous design, but it would need quite a whack to break the tube.

Btw the hull is only underwater by an inch or so at the top of the rudder.

One other point: a charterer grounding the boat hard may not tell the charter company when returning the boat. Inspecting the quadrant lazarette for leakage would not be a standard thing for the cleaners to do. So the next charterer may get a damaged boat...

Sent from a stupid phone that replaces words with weird stuff.

[MarkJ]

Useless f'ing forum software...

Sent from a stupid phone that replaces words with weird stuff.

[estarzinger]

Where I am on this:

1. I believe we can confidently say that something bad happened to the steering/autopilot/rudder shaft. The charter's heard a bang, and the video shows the rudder dropped a couple cm's. But we don't know if that was the cause of the sinking or a symptom of flooding from elsewhere. Some information of autopilot component mounting location would help suggest an answer to that.

2. The bang could be almost anything breaking - and we don't know what it was. In several Bendy installations I have looked at, I would have guessed that the autopilot drive mounting would be the first thing to break.

For the rudder to drop, either the stop collar or the top of the shaft tube had to be displaced. The stop collar is shown as a separate piece in Mark's photo's but in my photos (which are later models) it appears they are using the quadrant (or tiller arm) to do the combined job. So shearing off the quadrant could have been the bang, and cause the rudder to drop, and jammed it so the emergency tiller did not work - that seems the most likely explanation for the reported combined steering/rudder failures.

I might note that we don't know exactly when the rudder dropped. The charterers appear to have towed the boat backwards for a while. That can be be quite hard on a rudder, especially as it seems to have been hard over and not centered. So, it is possible that it was further damaged during the tow and not during the original event.

3. But the quadrant (or whatever it was) breaking alone did not cause the sinking. The shaft tube would have to crack (in a big way and near its bottom end) for this to be the cause of the sinking. And that tube should be very very hard to crack. I am aware of a number of cases where the rudder shaft broke and the tube did not crack. I am aware of a whale strike that took the rudder, tube and a piece of hull with it. I am not aware of many cases where the tube cracked by itself. There was at one that was an original factory defect.

4. The rudder (and hull around it) does not show any damage or scuff marks to the blade in the video. So I think we can be relatively (not 100% certain but close) certain that these charters did not run the rudder aground. And also pretty certain that there was no massive UFO strike on this charter.

If prior charters grounded the rudder, then the yard 'fixed' and painted over the damage. The bending forces from a grounding are strongly localized to where the rudder exits the hull.

If I had to speculate on how the autopilot could have cracked the tube, when the engineering says it 'should not be be able to' . . . I would postulate (a) that the bottom area of the tube had been weakened in a prior grounding (Note: it would be interesting to know the maintenance records on this boat because I would think that grounding would have had to do noticeable and significant damage to the rudder in order to effect the string of the tube fixings), and (b) that the broken quadrant pushed by the autopilot somehow acted as a 'cam' (eg extra leverage) pushing on the shaft and tube, and (c) levering on the bottom end of the tube, cracking breaking its bond to the hull.

(5) The rudder tube bottom is very near the surface - usually at the waterline in the ideal designers displacement and waterplace, and a couple inches down in the actual real world. To create the sort of flooding rate we see here, would have required the open surface area of like a 2" hole, right at the bottom - remember that most of the tube is above waterline so cracks in most of it except the bottom would not create serious flooding. That means essentially the bottom of the tube pretty much entirely disconnected from the hull (remember there is still a shaft in the tube/hole plugging. It would be interesting if the charterers took any higher resolution still pictures of the last moments. We can't see enough detail in the video, but zoomed in with a high rez still I would think there was the possibility to see if that sort of really significant damage was there.

I can well imagine the quadrant shearing off as a 'bang", but I have a hard time envision how getting the bottom end of that tube entirely off would happen with a 'bang' - I would have thought it much more likely to be a ripping/tearing. There is a lot of reinforcing that would have to go and it would most likely 'zipper' rather than go in one shot.

6. All in all, after working my way thru how this could happen with 'autopilot as cause' . . . I continue to think the flooding came from some other more likely failure in the boat. Again, it would be interesting to know where the autopilot components were mounted - most especially the 'other end' of the rudder reference wires.

way up thread I wrote :

Count the ways . . . .
1. broken hose or thru hull or transducers
2. leaking rudder shaft seal
3. leaking sail drive seal
4. broken rudder shaft (looks like not from the video)
5. leaking keel bolts/joint (have to be really serious, much less likely than the above to suddenly start happening from nothing)
6. cracked hull (no discussion of a collision so unlikely)

So its 99% 1, 2, or 3.

Because of the design we now know it was not #2 (no real 'seal' with that tube) so I figure #1 or #3.

[barnakiel]

If a rudder is built so that it may sink the boat, there should be a dam. Or else the rudder should be built strong so that it can not fail in a way that allows water in. Full dot. Build well, sail safe.

Same issue around the drive.

If a boat sinks in easy conditions and the damage is from the rudder or engine area, clearly there is a design issue that makes this specific design / design style / unsafe and not suitable for open water passages.

EU regulations are written by ignorant regulators, not by industry experts. Bennes and other modern plasticky boats are not built to LLoyds A1. Or are they?

We get what we pay for.

b.

[Kenomac]

Originally Posted by Terra Nova

What competent crew would NOT check a (especially charter) boat's bilge pumps before a passage? You might assume your own boat's pumps have not failed since you last checked them. But an unfamiliar charter boat? Serious incompetence, there.

And how long can a spinning wheel prevent the helmsman from shutting off the autopilot before hitting the stop? A few seconds?

Some of these coastal cruisers like our previous Hunter 450 don't have a proper deep bilge, so if the water is coming in too quickly for the pump to handle the intrusion, the pump shorts out just as soon as the water level goes above the pump.

Nothing to do with crew competence, more to do with boat design.

Manual bilge pump? That's a laugh.... nothing more than a "feel good" option when the water is coming in at any significant rate.