Bayesian Interim Report

WRT the engine room vents even if open with the engine room watertight doors closed as they almost certainly would be would there be sufficient volume of water let into the boat to sink her? I think probably not.

I can't answer that, and clearly the ventilation goes throughout the vessel. However, yeah, depending on the size of the ventilation pipes maybe the vents aren't the liability they appear to be in normal use.

Although a) I'd have thought the NAs who've commented on the vents would have spotted that and b) in this specific case I have a vague recollection that the engine room door was open because the engineer needed to go to the bridge as part of the process to get underway which he had initiated.
 
They were unlikely to have been left open deliberately with the air conditioning but could have been opened by crew or passengers to escape or leave the boat. It's also possible that even had they been closed their weight could have caused them to open at the extreme angle of heel.
I think in the MAIB report is says a crew member dived down to open then - so 1. they were closed, 2. the boat flooded anyway, 3. this was presumably the most obvious escape route which brings us back to the question of emergency escape which the MIAB say they will cover later.
I calculate one of those would let in 15pc of the vessel's total weight per minute if they were half a metre under. So there's no way that upside down this vessel wasn't going to sink once inverted with or without patio doors.
Assuming the engine room was not closed to the rest of the vessel. Again that brings us back to the question of would the crew have closed more of those risks if they perceived a risk of capsize at anchor.
 
According to previous captain -

The downflooding angle for Bayesian was around 40-45 degrees… much less than the AVS. So, unless the vent dampers are closed (which with HVAC systems and generator running they would NOT be as they need to be open for that), the vessel will start to flood rapidly if heeled more than the downflooding angle.

Former Bayesian captain offers insight
 
b) in this specific case I have a vague recollection that the engine room door was open because the engineer needed to go to the bridge as part of the process to get underway which he had initiated.
It was confirmed as closed early on with diver video.
 
I think in the MAIB report is says a crew member dived down to open then - so 1. they were closed, 2. the boat flooded anyway, 3. this was presumably the most obvious escape route which brings us back to the question of emergency escape which the MIAB say they will cover later.

Assuming the engine room was not closed to the rest of the vessel. Again that brings us back to the question of would the crew have closed more of those risks if they perceived a risk of capsize at anchor.
Reading the interim report there is no indication of where the initial ingress took place other than the water came over the starboard rails and then down the internal stairways. Looking at the deck plans and pictures the only aperture for that to happen is the aft saloon doors which doesn't chime with C/O who was in an air pocket in the saloon diving down to open doors weighing several tonnes under water with no power??? The chronology surrounding the rescue and opening of the port forward wheelhouse door is difficult to follow and understand also.
In view of that I will wait to see what the full report states.
 
I am hesitant to post or question upon this subject because lives were lost, but as the thread is active and not locked perhaps it is acceptable?

I am ignorant (comparatively) of super yachts and their design.

After having read a bit of this thread that is too long for me to have read every single post, is it a case that the boat was possibly poorly designed? Is that possible?

Sir Bayden Powell nearby dragged but survived.

My sailing is simple in comparison and the most expensive boat I ever sailed was made by Oyster.

I know next to nothing of naval architecture and super yachts but I am saddened by this episode and if lessons can be learned that would be great and some people here have experience and knowledge that is professional and not that of an amateur sailor such as me.

Discussing it even in such a ‘location’ as a forum could lead to possible answers (since some posters may be experts for all we know); possible naval architects?

I have been surprised to see the vast knowledge and experience of posters; there are even RNLI volunteer life savers posting on here I have seen.

This is clearly not a forum of simple day sailors (as I consider myself).

So, if not indelicate, does my question consist of any plausibility? Was it possibly (“POSSIBLY”) with only the information we have that is not complete, a poorly designed yacht?

Or is it far too complex to answer given the fact that people have mentioned vents watertight hatches left open (engine room) and so on?
 
Sir Bayden Powell nearby dragged but survived.
It was an extremely localised weather event. The boat wasn’t poorly designed for the intended purpose but the design did contribute to the sinking. These are separate things though, which I think many struggle with.
The other boat didn’t experience the same weather so isn’t really a good comparison, we have no way of knowing what would happen if their positions were reversed.
 
It was an extremely localised weather event. The boat wasn’t poorly designed for the intended purpose but the design did contribute to the sinking. These are separate things though, which I think many struggle with.
The other boat didn’t experience the same weather so isn’t really a good comparison, we have no way of knowing what would happen if their positions were reversed.
How far away was Sir Bayden Powell to have avoided the weather?

I thought she was very close?

Is the weather that localised ( to within a few 100 metres?)
 
@Cerebus I don’t think anyone knows for sure how strong the wind was that hit the Baysien. It was undoubtedly extreme. Nor do we know for sure how different the weather that hit Sir Baden Powell was - one theory is Baysien was hit by a tornado which missed the SirBP but the MAIBs calculations show it doesn’t need to be a full on tornado to knock the Baysien flat, if the wind direction is wrong.

Was it a bad design? That will probably be debated for decades. It is certainly a significantly different design to the SirBP, but then it has a quite different purpose. All designs have limitation and the learning here will be how they are understood, communicated and acted upon. All weather systems have uncertainty, and again the learning here may be how people consider what the worst case might be. We’ve yet to hear it but the MAIB has hinted there might be be more lessons to learn on hot vessels facing these conditions deal with them which may have lessons for designers or operators.
 
@Cerebus I don’t think anyone knows for sure how strong the wind was that hit the Baysien. It was undoubtedly extreme. Nor do we know for sure how different the weather that hit Sir Baden Powell was - one theory is Baysien was hit by a tornado which missed the SirBP but the MAIBs calculations show it doesn’t need to be a full on tornado to knock the Baysien flat, if the wind direction is wrong.

Agree. We're never going to know. It's certainly consistent with a 50m patch of localised downdraft but it could have been something else. Maybe the same weather caught the other vessel at a slightly better angle, maybe the other vessel was a harder target. I can't imagine either vessel had a mechanism for measuring downdraft so it's guesswork.

TBH, converted tug to sailing boat isn't screaming "seaworthy" at me. (How did that work out for Tilman.) So I wouldn't be holding that up as the gold standard.
 
It would not be unusual for the vessel to have data loggers and that the vessels instrument system will have recorded wind speed and direction (amongst other things) and that it is stored in memory and be capable of being extracted when the vessel is recovered. Time will tell.
 
@Cerebus I don’t think anyone knows for sure how strong the wind was that hit the Baysien. It was undoubtedly extreme. Nor do we know for sure how different the weather that hit Sir Baden Powell was - one theory is Baysien was hit by a tornado which missed the SirBP but the MAIBs calculations show it doesn’t need to be a full on tornado to knock the Baysien flat, if the wind direction is wrong.

Was it a bad design? That will probably be debated for decades. It is certainly a significantly different design to the SirBP, but then it has a quite different purpose. All designs have limitation and the learning here will be how they are understood, communicated and acted upon. All weather systems have uncertainty, and again the learning here may be how people consider what the worst case might be. We’ve yet to hear it but the MAIB has hinted there might be be more lessons to learn on hot vessels facing these conditions deal with them which may have lessons for designers or operators.
It would be interesting to know what the AVS and downflooding angles are for the Sir Baden Powell. It would not surprise me if these were no better, or indeed worse, than Bayesian - certainly if there was any imperfection in the furling of the sails on the foremast yards.
There have sadly been thousands of lives lost with old sailing ships capsizing and foundering in storms - some in relatively recent years.
The Baden Powell may just have been less unlucky.
 
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