C&N managed yacht sinks off Sicily, 7 missing

[Statistical]

Originally Posted by Invictus69

I would not dispute the yacht integrity, at the end, it was crossing oceans for 15+ years (built in 2008). What I heard is that the taller mast was installed subsequently (not sure if that's correct) and if true, whether that may have distorted design stability etc.


Some of you may remember that Oyster yacht which broke in half and sank near coast of France or Spain some years ago whose owner wanted it extended by few meters from its original design.

Boat sinkings even for poorly designed boats aren't that common. The fact that it didn't sink until now is not a guarantee it is a good design.

One that struck me is the vessel has an AVS of only 75 degrees. I don't know anything about megayachts but under CE classification for yachts bought buy us mere mortals that isn't even good enough to meet the minimum requirement for Category B (offshore) much less Category A (ocean).

Crews should avoid getting knocked down but it does happen. Some knockdowns are steeper than others. I have seen more than one vessel knocked down with their mast touching the water (so h heel angle of >90) and right back up.

According to the yacht designer 75 degrees is as good as it gets. 76 degree heel yeah you will sink and half the passengers die just impossible to make boats better than that. Totally unavoidable just an absolute reality of boats according to the manufacturer.

Now did the crew also make mistakes which increased the level of heeling and reduced its potential to bounce back? Likely. In any disaster there is rarely a single cause but rather the confluence of events, actions, and design choices but the yacht designer tooting his own horn with the vessel having a AVS of a "whole 75 degrees" just rubs me the wrong way. 75 degrees is ****. I wouldn't take a vessel with an AVS of 75 degrees on a daysail in brisk conditions. If this vessel had an AVS of 90 or 110 degrees would she have sunk even with the crew making mistakes?

[MathiasW]

You do not swing at some 50° or so back and forth in light winds around an imaginary point which is not the anchor itself.

[Franziska]

Originally Posted by MathiasW

True, but the track shown seems it was doing happily movements along a perfect arc and then suddenly broke off. In light winds, you tend not to have nice arcs but a track that wanders all over the available space, over time.

True, your right about that.

[dannc]

The storm had hurricane force winds. Then there appears to have been a waterspout whose wind speed I have not seen stated. It would appear that the waterspout caused the heeling and sinking.

The ship dragged at some point. Was this caused by the hurricane force winds or the water spout? Not sure it really matters and she was dragging offshore not onto a lee shore. The video of the ship shows the ship dragging not getting knocked down.

The garage doors would almost certainly have been closed since the storm hit early in the morning. A person who have served on these type of ships said once guests were back on board, boats were stored and the hatches closed. This makes sense from a seamanship perspective but also for security. It would be shocking/surprising if the garages were open.

One of my questions was what was the AVS if the keel was down. According to the builder, the answer is 88 degrees. Keel up and the AVS was 73. If the keel was down, the ship would have had a better chance of survival but not a much better chance. However, the difference of one degree could have made a difference between floating and flooding. An AVS of 88 is not a high number.

There is some very interesting information in this video, https://youtu.be/OFOpw5UCn8s. This video then links to another video,

https://www.youtube.com/watch?v=OqAS-eCM9B0

which has a comment from Chis Freer.(@chrischamberlaine4160 )which is mentioned in the first video.

The ship's mast has huge windage, see Freer's comments.

The other interesting piece of information is from a person who served on these ships. The doors, and the photos shown in the video, were glass doors, would swing open when the boat heeled... The doors in the video were huge, maybe 6-8 feet wide and tall.

Accusing the captain and crew is not justified until the final report is published. The captain is responsible at some level simply because he is the captain but everything is pointing to a very specific chain of events, some in the captains control, the keel position being the main one, but many of the issues are from the ships design and build.

The captain has no control over the size and windage of the mast and rigging or the designed AVS. The doors swinging open would be a design/build issue that should have been fixed, which does rest on the captain but also the builder. The builder needs to stop throwing stone because his house is made of very thin glass.

[Statistical]

Divers recovered the final body. Million to one longshot that anyone would be rescued but still sad to confirm.

[Iron E]

Originally Posted by dannc

[SIZE=2]There is some very interesting information in this video

In the first comment, Chris makes some great points, including:

I’m sorry to say that size matters to a superyacht owner and naval architects are seduced into providing solutions.

As yacht size increases the resistance of the hull reduces in proportion, so less sail area is required to adequately power longer yachts. But these floating fashion items are driven by appearance and bragging rights - and you lose prestige if someone has a bigger mast than you.

Always the status pecking order questions are – how big – how fast – what cost – and is it black? If you designed Bayesian with a reasonable sail area and a ‘normal’ mast she would not look impressiive – which is what superyachts have to be.

[MathiasW]

Originally Posted by dannc

The storm had hurricane force winds. Then there appears to have been a waterspout whose wind speed I have not seen stated. It would appear that the waterspout caused the heeling and sinking.

The ship dragged at some point. Was this caused by the hurricane force winds or the water spout? Not sure it really matters and she was dragging offshore not onto a lee shore. The video of the ship shows the ship dragging not getting knocked down.[SIZE=2]

All very well, but the other vessel experienced similar conditions - their captain mentioned 12 BFT. But they did not drag, and took active measures to prevent that from happening.

Paying out as little as 65 metres of chain at that kind of water depth is simply no good seamanship, if there is any indication of bad weather coming. And there were - see the local fishermen. With this amount of chain and that anchor depth, it would take only 17 kn of wind to lift the last link of my chain. So, it would not have taken a waterspout for their anchor to start dragging, far from it.

[Bowdrie]

I don't know what techniques may or may not be used, but has there been any talk about attempts to raise the vessel?

[boatman61]

True but, both the masts combined likely added up to 25metres less than Bayesian plus they were not hit by the same forces.
Where do you get the anchor length data from. and what size chain and anchor does she have.

[MathiasW]

Originally Posted by boatman61

True but, both the masts combined likely added up to 25metres less than Bayesian plus they were not hit by the same forces.
Where do you get the anchor length data from. and what size chain and anchor does she have.

just looking at the swinging radius as recorded on vessel finder (please note the scale provided by vessel finder).

[boatman61]

Originally Posted by MathiasW

just looking at the swinging radius as recorded on vessel finder (please note the scale provided by vessel finder).

I was referring to your 65metres of chain..

[MathiasW]

Originally Posted by boatman61

I was referring to your 65metres of chain..

I know! And that is my answer. From the swinging radius as shown in vessel finder you can infer the maximum length the chain could have been. Given the scale of the diagram that vessel finder provides one works it out to about 55 metres of swinging radius, and given the water depth there, a bare-taught chain could not have been longer than 60-65 metres.

[boatman61]

Originally Posted by MathiasW

I know! And that is my answer. From the swinging radius as shown in vessel finder you can infer the maximum length the chain could have been. Given the scale of the diagram that vessel finder provides one works it out to about 55 metres of swinging radius, and given the water depth there, a bare-taught chain could not have been longer than 60-65 metres.

So.. She sank in 50metres and was being blown to sea then what was the depth she originally anchored in.
15 metres, 20 metres.. and the swing is likely before the sudden wind hit.
Comparing chain and hook for a 51ft tri and wind effects is a lot different to likely chain and hook sizes for a boat that size and weight..
He's not perchance a CF member who's fallen for the silly adequate scope setting talked about on here..

[MathiasW]

Originally Posted by boatman61

So.. She sank in 50metres and was being blown to sea then what was the depth she originally anchored in.
15 metres, 20 metres.. and the swing is likely before the sudden wind hit.
Comparing chain and hook for a 51ft tri and wind effects is a lot different to likely chain and hook sizes for a boat that size and weight..
He's not perchance a CF member who's fallen for the silly adequate scope setting talked about on here..

The view on vessel finder shown here originally in one of the earlier posts was including depth (in feet), which gives at least an indication of the anchor depth. More precisely, in vessel finder, if you hover with the cursor over the point where they presumably dropped the anchor, you get the GPS coordinates of that point. Taking those coordinates to my Navionics map tells me they anchored just within the 30 metres contour line. So, that is quite some anchor depth for a chain only 65 metres long.

Your last comment is puzzling me and I do not seem to be able to understand it. But just for clarity, I do not believe in scope, but in (possibly truncated) catenary.

And yes, my boat is different, but things scale. Chain thickness will be different, anchor will be different, but it all scales such that it works. If anything, just for this very reason of scaling, the chain they require will be even longer than mine.

PS: At 30 metres of anchor depth, to give a swinging radius of 55 metres, perhaps you need 70 metres of chain, but that is still far less than needed....

[MathiasW]

And as said before, the swinging pattern seen on vessel finder strongly suggests that the entire chain was involved in this swinging. With such a short chain, it does not take a lot of wind to make the last link of the chain lift off the seabed.