Oceanis 485 steering failure

[Highland Fling]

Originally Posted by transmitterdan

I'm with Evans as to likely causes. Rudder seemed to go stop to stop more than once. The AP control location required the driver to reach through the wheel spokes to turn it off. Really poor design there.

Would like to hear how long it took to sink. A through hull would take more than a few minutes. A broken rudder post or stuffing box might take less time.

I would love to hear how long it took to sink.....and with seven on board could they not have kept up with the water ingress with a bucket or two pots and pans etc.

Under tow they could have run the engine in gear to reduce the load on the towing boat and increased their SOG to ....." ALSO they could have used the engine seawater pump as a bilge pump disconnecting it from its seacock after closing it and using the engine as thier only functioning bilge pump.

The rudder will be positively buoyant so even if as I suggested previously the autopilot split the rudder post in half at the autopilot tiller connection they would lose steering but should not be in danger of sinking as the rudder post will still be filling the rudder tube hole AND if the top of the rudder tube is above the static waterline.

Even if it were not the seal would be should be intact as it will be below the quadrant and the autopilot tiller assuming the pilot is not actually connected to the quadrant.

Sadly my Beneteau experience expertise is now well out of date and I have no actual experience of the rudder and steering set up on an Oceanis 48 as I am now totally retired.......so that is just more guesswork and supposition with a few assumptions thrown in for good measure.

[Highland Fling]

Originally Posted by estarzinger

.......

I have no intention of paying the I am more qualified than you game and listing my qualifications here.

And your first post here suggested it was a shaft log stuffing box issue.......on a boat with a sail drive....:-(

MOST bennies have cast iron keels......the bottoms of these keels are never properly prepared my keel needs reworked every time we haul out that is not an indication of a grounding just another good reason to have a lead keel

CR had groundings that were never followed up with investigation or repairs.

It is quite easy to identify detachment of the IGS in Bennies

BUT you have to look and know what you are looking for, experience counts a lot here doubly so with the repairs especially writing the repair specification for the repair and ensuring that the repairer follows the specification to the letter. That last one is a 24/7 task.

We can pontificate for days here and won't learn anything about this sinking I would hope that some of these threads have real value this one well I have my doubts.

[estarzinger]

Originally Posted by Highland Fling

It is quite easy to identify detachment of the IGS in Bennies

The MCA, all the repair facilities they interviewed and the designer disagree with you:

"Owing to the continuous nature of the matrix where solid floors are in place, particularly in the area of keel attachment, it is not possible to see the bonded areas. It is therefore difficult to readily identify areas where a detachment has occurred, meaning that it is possible for a detachment to remain undetected."

"All of the repairers agreed that it was very difficult to identify areas and the extent of matrix detachment, . . . . . meaning that it is possible for a detachment to remain undetected."

"..... it is unlikely to be sufficient to identify areas where full detachment has not occurred and some bonding exists."

And from prior rudder loss investigations . . . there can be quite difficult to identify latent damage there also.

BTW . . . if I have done my math correctly the 20%/year number means that 1% of charter's touch the bottom - do you really find that so hard to believe? (800 boats x 20% ground/year)/(800 boats * 18 charters/year/boat) = 1%). It might be as much as 2% depending on boat utilization.

[scuba0_1]

Why were they unable to stop the wheel from turning. I was able to stop my wheel when it went crazy on a trip with grinding of course but I could hold. it and disengage the ap. What's the case that no one was at the wheel.


Sent from my SM-N910V using Cruisers Sailing Forum mobile app

[estarzinger]

Originally Posted by scuba0_1

Why were they unable to stop the wheel from turning. I was able to stop my wheel when it went crazy on a trip with grinding of course but I could hold. it and disengage the ap. What's the case that no one was at the wheel.


Sent from my SM-N910V using Cruisers Sailing Forum mobile app

The OP says they were a bit afraid of getting their hand stuck in the wheel so took a moment to figure to move and reach around the wheel to hit the autopilot.

Let's assume #1 that the autopilot failure is the cause rather than the symptom of the water ingress. And #2 that per the op they correctly inserted the emergency tiller and it did not give them steering. That would most likely imply two things (a) that the autopilot had torqued the quadrant and that had sheared off the head of the rudder shaft - which is why the emergency tiller did not give them steering. (b) the shaft was still in the boat, but they had water ingress, so that torquing (and subsequent rudder shaft movement unconstrained by an upper bearing) damaged the rudder bearing seals, which started slowish but steady leaking. This has historically proven a hard leak to stem.

The OP does not say whether they looked inside the compartment at the quadrant/rudder shaft. If they had, this all should have been apparent, and the shaft would have been moving rather vigorously in the lower bearing, as it would have been detached from its upper bearing.

The key question with that scenario is that I would have thought the quadrant would have come loose from the shaft without tearing the head off. That would be the prefered failure mode. It would be interesting to know exactly how the quadrant is attached to this rudder.

I might note that steering with emergency tillers is often quite a bit more difficult than people expect. And that could have been the reason for them saying they were 'unable' to steer with the tiller, rather than damage to the shaft. It would be interested to know if the 'failure to steer' was because it was hard, or because there was no resistance at all. That would tell us quite a bit about the shaft damage.

[monte]

I didn't see any pots that far N of Guadeloupe when we sailed up a few weeks ago. The first coastguard on the scene (in the pic) jumped from a chopper. A bIt hard to jump with an emergency pump I guess. By the time the boat arrived with pumps the decks were awash. All this on a fairly calm afternoon just ten miles from Guadeloupe, between 1230 ( first call to coastguard ) and 1800. Btw, three charter boats that I've seen have managed to hit the well charted reef a few hundred meters behind where we are anchored in the last few weeks, some at speed... They do stop in a hurry. I have no idea on the statistics. Also, towing a dinghy between Antigua and Guadeloupe isn't really advisable as far as I'm concerned. Even if conditions were pretty benign, there's always a chance of catching the painter in the saildrive and making a big 'ole.

Edit: actually I tell a lie. 1 charter and 2 private yachts hit the reef.. that I've seen...

[barnakiel]

Originally Posted by partyanimal

the location was 12Nm north of Guadeloupe

Looking at the video I think I can see the Tete (or is it the Kahouanne?).

Then the location is not 12 miles off. More like 5 miles or thereabouts, likely within the still shallow patch.

b.

[monte]

Originally Posted by barnakiel

Looking at the video I think I can see the Tete (or is it the Kahouanne?).

Then the location is not 12 miles off. More like 5 miles or thereabouts, likely within the still shallow patch.

b.

Yes Nick, that was 5hrs after the initial problem though. I guess the managed to tow it 6-7 miles in the mean time.
3 miles North of Kahouanne

[Denise-SJD]

Originally Posted by Highland Fling

Twin wheels yes two rudders I don't think socan someone who knows the Oceanis 48 intimately confirm rudder configuration?

We own a 2014 Oceanis 48 with sail drive (no dock and go). We only have one rudder.

Will be following this closely

[Denise-SJD]

One rudder

[Tomaz473]

I watched the video.
I looks to me there is some white spot (no antifouling) where rudder enters the hull.
This might be part of shaft visible or damaged hull.
I think it is possible they might have hit a log. A coconut log can be half submerged as wood density can be almost equal as water density. Waves are trashing the log, so it is possible to miss it with the hull and keel and hit it with rudder. Perhaps also with sail drive. Possibly it could be a long log, got between sail drive and rudder with one end, then boat forward movement would make the log rotate creating a large momentum on a rudder and sail drive. Maybe autopilot did not turn the wheels but the log did it. It could have bent or broke the shaft in the process. It could have also bent the sail drive enough to enable water ingress.
As the log broke rudder shaft at the quadrant no emergency steering was possible.
Just one theory. I am not saying this have happened.
To me more likely version is that some time prior the rudder hit some rock, cracks in the shaft were not detected and cracks were developing further with use. They hed second reef on main, so I guess there was some wind. The area N of Guadeloupe is known for some confusing seas. Nothing big, but could be enough to brake cracked rudder shaft.

About bailing water with a bucked: this boat have internal volume of more then 50 cubic meters. It filled in 5 hours. They could not bail out 10 tons of water per hour. This is more then 150 l a minute (40 gallons a minute). One can do this for few minutes, not for 5 hours. Coast guard probably sent them off the boat anyway. They must save lives, not a boat. Imagine crew would be still bailing water and someone would get tangled and drown when the bot would go down. Coast guard can not take this risk. I am pretty sure that standard procedure is to send crew to safety first, then try to save the boat. They also know it is a charter insured boat. Not worth risking a life of a tourist for that.

[MarkJ]

Originally Posted by Tomaz473

.

About bailing water with a bucked: this boat have internal volume of more then 50 cubic meters. It filled in 5 hours. They could not bail out 10 tons of water per hour. This is more then 150 l a minute (40 gallons a minute). One can do this for few minutes, not for 5 hours

Yes, great point.

We need less stupid phrases like 'scared man and a bucket' and more thought to reality.

Also I think you and Evans must be close to the mark, that rudder shaft tube must be involved. If the shaft tube fractured at its base (previous grounding?) and the rudder and quadrant was flapping about the AP may have being trying to correct course at each flap. Thus the AP was a symptom of the damage causing the water ingress.

My rudder shaft tube is 2 or 3 inches in diameter. Even with the rudder still inside there's a hell of a lot of water going to leak in... and even if you have underwater epoxy putty it won't work cos the rudder is still flapping about.


Mark

[estarzinger]

^^ I believe if you look more closely, you will find that that 'white area' is on the rudder shaft rather than on the hull - the lower part of the shaft which turns/rubs on the lower bearing.



It is possible that the shaft has dropped down a couple cm's from its normal position, and that is why so much white us showing. That would indicate some damage to the shaft and associated hardware.

But The rudder is quite 'stable' and not moving in the sort of way that I would expect if the shaft was broken and detached from its upper bearing inside the boat. For me at least, that indicates that the head of the shaft was probably not broken off. And that the 'failure to steer with emergency rudder' was either due to the autopilot/quadrant being jammed inside the boat, or the crew simply finding it much more effort to use the emergency tiller than they expected. You should not ever count on a typical bilge pump to bail you out of a below waterline breach - you need a serious crash pump for that.

There is also no sign of the mythical pot/trap. So far I see no sign that this was caused by any outside influence, rather was simply a failure of a boat system - either the autopilot failed and broke the rudder seals or one of the other systems (I listed above) failed and shorted out the autopilot as a side effect of flooding the boat.


As an aside - in a collision (or torquing) with an external object, like a log, usually the damage to the shaft is right at the bottom of the lower bearing, and the rudder snaps right off and is gone.

I agree with you about bailing by bucket.

As a further aside . . . it is eye opening for anyone who cares to examine how ineffective typical bilge pumps are in an emergency situation. They can handle very slow weep and random condensation and rain down the mast . . . but are entirely unable to keep up with a significant below waterline breach. The cooling water">engine cooling water circuit is also not a very high volume pump. Just for some quick numbers - a 2" hole 2' below the waterline will flood 113 gallon/min. The very largest Rule bilge pump (and most boats have bilge pumps significantly smaller than this) will pump 36 gallons/minute against a (typical) 6.7' head. And a 75hp yanmar running flat out pumps 14g/minute of cooling water. On the other hand, a 2" crash pump will move 175 gal/minute against a 7' head - they are also much more impervious to (the almost certain) debris in the water than the typical bilge pump or engine cooling pump - but most boats don't carry these.

[sigmasailor]

This would not have happened with a catamaran.

[HappyMdRSailor]

Good stuff Evans... Thanks for your effort !