The design of the boat meant that she had a lifting keel that would be down while sailing, this would have been up at anchor. Furthermore while sailing they would close various vents to stop water flooding when healed. It is probably a combination of design factors that caused the sinking, that mast just being one.
Big enough v, the total moment is great enough. Note that IMO severe wind and wave (weather) criteria (which is not mentioned in T&S nor in LY2 but is a treaty Loadline convention requirement uses 503 Pa or about 55 knots.
This wind was way way above that. Catastrophic downflooding points (multiples) start at 40 degrees, and 3 in play by 50 degrees.
I am curious whether she met IMO weather. She may not have.
The Times article on the Bayesian sinking is perfectly illustrative of how the mainstream press barrels blindly down the tracks of journalism, believing that a writer does not need an iota of familiarity with or expertise in the subject matter being covered. And, oh yes, does not have any responsibility to even acknowledge the contribution of those who supply the underlying knowledge or analytic acumen that make the piece even minimally intelligible. IMO, one should always make it clear that significant contribution -- meaning more than 5 minutes -- requires at least a line of attribution, if not a two or three line background blurb. Cheers!
Unforunately true. They also made some errors. Ketches don't have foremasts.
And they went straight for the Tall Mast Scapegoat Narrative. Terribly flawed. The real issues appear on ANY MCA Red Ensign Part A "sailing" ship which is right at minimums. Yes even a ketch would have foundered were her numbers the same.
I wrote a nice note to the author...haven't heard back.
Roger Long and Tad Roberts performed yeoman service in their analyses, while the safety board investigators still plodded along with not much more of a clue than the NY Times reporters. The most likely answer(s) is/are right in the Stability Book: deficient rate of development of a positive righting arm when heeled, coupled with badly placed potential down-flooding entry points and a half-assed plan for isolating and containing flooding via highly questionable WT compartment doors. https://www.portroyalgroup.com/p/bayesian-disaster-follow-up
The T&S booklet shows that she met all LY2 requirements except in Light condition. That booklet is missing some key information, and the presentation of downflooding points is more confusing than it should be. Why are they presented in two different places (table, and drawing, many pages apart) and grouped but with no explanation of how the locations work considering the grouping? The drawing shows that all but groups D and E were remotely controlled. D & E are accommodations ventilation and downflood at mid 50s. Together they amount to about 0,2 m^2 and they flood multiple compartments other than the engine room. Certainly a significant role in the sinking, as the engineroom by itself would not have sunk her. (However, likely flooding the ER would have reduced her range to vanishing stability, possibly to less than the angle she was rolling through during engine room flooding).
While at sea, these accommodations vents should be closed in bad weather while motoring or sailing, and hopefully all the time while sailing. The book is not specific about it but leaves to master, see page 19.
But this vessel was in harbor.
The downflooding points were most likely all open, and although the shutters on the two largest and lowest angle sets were remotely controlled (Groups A, and C, engineroom, and lazarette), clearly there was no time nor person on station to carry out closing them when the gust hit. I believe this vessel is 1 compartment subdivision, so actually Laz + ER and she's a goner anyway.
One of the strange things is that LY2 does not cite IMO weather criteria. I wonder if this vessel passed it? I would expect the flag state to invoke it anyway but I have not seen anything about that. A US flagged vessel of this type would have to meet the more stringent 46 CFR 171.055 as well as 170.170 "weather criteria" unless exempted under the "unusual proportions and form" clause, and the IMO criteria if sailing internationally. But the IMO weather criteria uses approx 55 knot wind in its calculations and as with essentially all the baked in assumptions of stability criteria, is geared to at-sea conditions, not in port.
As an aside, look at her Max KG curve. This boat is NOT a sailboat! Over MOST of her displacement range, her KG is too high to sail. She has to be full load to sail and meet the (lax) MCA LY2 sailing criteria.
I wonder Peter at what point you stop being a 'source' to mainstream media, and become respected as a journalistic outlet, deserving of credit for diligent, original work?
I'm only a casual dinghy-sailor, not even a boat-owner (unless kayaks count), but this is an area requiring serious expertise and I appreciate you taking it seriously.
Journalists are by definition generalists. I provide a forum for experts who might not otherwise be widely heard. That is what I do. That and ask questions.
So any generalist knows the right questions to ask and when to be satisfied with the answers, Peter? You just wrote an article illustrating how what the NYT did was corroboration, quote-checking and graphic design. It's fact-checked news aggregation and we're nearly at the point where AI could do that. To the best of my knowledge, the original journalism was yours and you should be credited.
A proper sailing yacht doesn't downflood. Can roll over. These ships are not proper yachts. They are motorships with sailing rigs for fair weather sailing. Note the sailing manual. Note the stab book references dependence on active sensors and automatic sail controls to prevent steady heel beyond 25 deg.
Proper yachts can be knocked down and come back up. Been there done that. These are not proper yachts. They are odd ducks. Not even as seaworthy as an old fashioned "motorsailer" such as Phil Rhodes designed.
I fail to understand how a mast can bring down a ship with no sail, and yet doing serious navigation with 1,000 M2 of canvas
The design of the boat meant that she had a lifting keel that would be down while sailing, this would have been up at anchor. Furthermore while sailing they would close various vents to stop water flooding when healed. It is probably a combination of design factors that caused the sinking, that mast just being one.
F=p*0,5*rho*v^2
M=F*h
Big enough v, the total moment is great enough. Note that IMO severe wind and wave (weather) criteria (which is not mentioned in T&S nor in LY2 but is a treaty Loadline convention requirement uses 503 Pa or about 55 knots.
This wind was way way above that. Catastrophic downflooding points (multiples) start at 40 degrees, and 3 in play by 50 degrees.
I am curious whether she met IMO weather. She may not have.
P = projected area, F=force,rho is air density, v is wind, h is lever, M is moment
The Times article on the Bayesian sinking is perfectly illustrative of how the mainstream press barrels blindly down the tracks of journalism, believing that a writer does not need an iota of familiarity with or expertise in the subject matter being covered. And, oh yes, does not have any responsibility to even acknowledge the contribution of those who supply the underlying knowledge or analytic acumen that make the piece even minimally intelligible. IMO, one should always make it clear that significant contribution -- meaning more than 5 minutes -- requires at least a line of attribution, if not a two or three line background blurb. Cheers!
Yep.
Unforunately true. They also made some errors. Ketches don't have foremasts.
And they went straight for the Tall Mast Scapegoat Narrative. Terribly flawed. The real issues appear on ANY MCA Red Ensign Part A "sailing" ship which is right at minimums. Yes even a ketch would have foundered were her numbers the same.
I wrote a nice note to the author...haven't heard back.
Roger Long and Tad Roberts performed yeoman service in their analyses, while the safety board investigators still plodded along with not much more of a clue than the NY Times reporters. The most likely answer(s) is/are right in the Stability Book: deficient rate of development of a positive righting arm when heeled, coupled with badly placed potential down-flooding entry points and a half-assed plan for isolating and containing flooding via highly questionable WT compartment doors. https://www.portroyalgroup.com/p/bayesian-disaster-follow-up
The T&S booklet shows that she met all LY2 requirements except in Light condition. That booklet is missing some key information, and the presentation of downflooding points is more confusing than it should be. Why are they presented in two different places (table, and drawing, many pages apart) and grouped but with no explanation of how the locations work considering the grouping? The drawing shows that all but groups D and E were remotely controlled. D & E are accommodations ventilation and downflood at mid 50s. Together they amount to about 0,2 m^2 and they flood multiple compartments other than the engine room. Certainly a significant role in the sinking, as the engineroom by itself would not have sunk her. (However, likely flooding the ER would have reduced her range to vanishing stability, possibly to less than the angle she was rolling through during engine room flooding).
While at sea, these accommodations vents should be closed in bad weather while motoring or sailing, and hopefully all the time while sailing. The book is not specific about it but leaves to master, see page 19.
But this vessel was in harbor.
The downflooding points were most likely all open, and although the shutters on the two largest and lowest angle sets were remotely controlled (Groups A, and C, engineroom, and lazarette), clearly there was no time nor person on station to carry out closing them when the gust hit. I believe this vessel is 1 compartment subdivision, so actually Laz + ER and she's a goner anyway.
One of the strange things is that LY2 does not cite IMO weather criteria. I wonder if this vessel passed it? I would expect the flag state to invoke it anyway but I have not seen anything about that. A US flagged vessel of this type would have to meet the more stringent 46 CFR 171.055 as well as 170.170 "weather criteria" unless exempted under the "unusual proportions and form" clause, and the IMO criteria if sailing internationally. But the IMO weather criteria uses approx 55 knot wind in its calculations and as with essentially all the baked in assumptions of stability criteria, is geared to at-sea conditions, not in port.
As an aside, look at her Max KG curve. This boat is NOT a sailboat! Over MOST of her displacement range, her KG is too high to sail. She has to be full load to sail and meet the (lax) MCA LY2 sailing criteria.
A sad reflection on the classification society involved. Displays not much more experience or good judgment than the Times reporters. https://www.portroyalgroup.com/p/anything-that-can-go-wrong-will-go
I wonder Peter at what point you stop being a 'source' to mainstream media, and become respected as a journalistic outlet, deserving of credit for diligent, original work?
I'm only a casual dinghy-sailor, not even a boat-owner (unless kayaks count), but this is an area requiring serious expertise and I appreciate you taking it seriously.
Journalists are by definition generalists. I provide a forum for experts who might not otherwise be widely heard. That is what I do. That and ask questions.
So any generalist knows the right questions to ask and when to be satisfied with the answers, Peter? You just wrote an article illustrating how what the NYT did was corroboration, quote-checking and graphic design. It's fact-checked news aggregation and we're nearly at the point where AI could do that. To the best of my knowledge, the original journalism was yours and you should be credited.
Thanks for your kind words, Ruv.
Should have had automatic closing engine room vents. A sailboat should be able to survive a 90 degree knockdown.
A proper sailing yacht doesn't downflood. Can roll over. These ships are not proper yachts. They are motorships with sailing rigs for fair weather sailing. Note the sailing manual. Note the stab book references dependence on active sensors and automatic sail controls to prevent steady heel beyond 25 deg.
Proper yachts can be knocked down and come back up. Been there done that. These are not proper yachts. They are odd ducks. Not even as seaworthy as an old fashioned "motorsailer" such as Phil Rhodes designed.
Hi Peter,
Quite a few others have also been interested in the T&S bklt. Could you send to me?
Thanks, Bill. I should have included it in the story in the first place. I just placed a downloadble link in the text of the story. Go to the website version (https://loosecannon.substack.com/p/how-our-bayesian-coverage-helped) and you can find it there.
Very much appreciated!
A prelim. teaser:
Edit:
Image did not stick
The link didn't work?
Your link worked. My image of some of my work didnt post.