Black Panther 1,701 Posted August 20 Share Posted August 20 All else aside this phrase caught my attention causing the 72m (236ft) aluminium mast to break in half and the ship to lose its balance and sink. I would hate my boat to lose its balance, maybe they should check alcohol levels. 1 Quote Link to post Share on other sites
aardvarkash10 1,070 Posted August 20 Share Posted August 20 these are journalists. They went through the arts stream at school, not the science stream. 1 Quote Link to post Share on other sites
LBD 170 Posted August 20 Share Posted August 20 Muppets But will be interesting to see what they find when they raise her, what actually did happen structurally. Quote Link to post Share on other sites
Nathan1000 4 Posted August 20 Share Posted August 20 This story is full of ???. An 56 metre super yacht sinking at anchor during the celebration of the owner being acquitted from a fraud case whilst in the same weekend the co defendant gets run over while jogging. 2 Quote Link to post Share on other sites
waikiore 451 Posted August 20 Share Posted August 20 Lots of misreporting going on, she was at anchor , she did go over in the tornado/waterspout just like the superyacht here at the silo a few years back. But how she sank so quickly?? V sad for those involved, designed by Ron Holland with a kiwi skipper and kiwi lawyer onboard who both survived . The sailing ship next door also got knocked about but it was all past fairly quickly, unlucky to be so early in the morning. Quote Link to post Share on other sites
aardvarkash10 1,070 Posted August 20 Share Posted August 20 1 hour ago, Nathan1000 said: This story is full of ???. An 56 metre super yacht sinking at anchor during the celebration of the owner being acquitted from a fraud case whilst in the same weekend the co defendant gets run over while jogging. so many lawyer and billionaire jokes come to mind, but still a bit early I think... Quote Link to post Share on other sites
K4309 358 Posted August 20 Share Posted August 20 1 hour ago, Nathan1000 said: This story is full of ???. An 56 metre super yacht sinking at anchor during the celebration of the owner being acquitted from a fraud case whilst in the same weekend the co defendant gets run over while jogging. A curious coincidence? God works in mysterious ways? Hired assassins getting better at covering their tracks? There are certainly enough 'coincidences' to raise some suspicions. I can't work out how a 180ft boat can sink at anchor in a thunderstorm. Yes, I know it can get knocked down and suffer downflooding, but we are talking a 180ft superyacht, not a mullet boat. And the neighbouring skipper reckoned it sank in 2 minutes. That is 120 seconds. You need a hell of a lot of downflooding to sink a boat that big that quickly... Quote Link to post Share on other sites
LBD 170 Posted August 21 Share Posted August 21 37.98416567333028, 13.709466983699906 Paste that in Google maps and zoom in.... It is not the boat in the news, but in the marina close to where she was anchored. ( This image has been on google maps for some time, I had found it before today) Quote Link to post Share on other sites
K4309 358 Posted August 21 Share Posted August 21 45 minutes ago, LBD said: 37.98416567333028, 13.709466983699906 Paste that in Google maps and zoom in.... It is not the boat in the news, but in the marina close to where she was anchored. ( This image has been on google maps for some time, I had found it before today) I can't find the name of that boat, but I remember reading about it. Or at least one very similar. If it is the one I was thinking of, it was a recently restored classic, or something notable anyway, sunk tied up to the quay. Was wanting to find the details to see if it was sunk due to weather or some other sort of random problem. You can see the masts sticking out on street view... 1 Quote Link to post Share on other sites
BNG 53 Posted August 21 Share Posted August 21 Pure speculation but perhaps they had the toys out and left the bomb doors open... sounds like it went down pretty quickly. 5 Quote Link to post Share on other sites
Black Panther 1,701 Posted August 21 Author Share Posted August 21 2 hours ago, LBD said: This image has been on google maps for some time, I had found it before today) What exactly do you do with your spare time? Quote Link to post Share on other sites
LBD 170 Posted August 21 Share Posted August 21 35 minutes ago, Black Panther said: What exactly do you do with your spare time? "To a man with imagination a map is a window to adventure"... google maps with satelite imagry more so. I found that sunken boat while crusing around te coast of Sicily on my laptop. (Not much else to do at night time at this mining camp. The other day I found Hyundai advertising in the antarctic... -74.62408062044808, 164.22446156852746 1 Quote Link to post Share on other sites
Kestrahl 10 Posted August 21 Share Posted August 21 One or more of the crew must have been awake, and can give an account of what happened.. Its all very vague. My guess - heavy alloy mast and keel up, it got knocked down and sat on its side filling up with water. 3 Quote Link to post Share on other sites
khayyam 95 Posted August 21 Share Posted August 21 Apparently she has a lifting keel. So if it was up, that would go some way to explaining the lack of stability. edit: Oh kestrahl I see you just said that, sorry! Quote Link to post Share on other sites
Deep Purple 530 Posted August 22 Share Posted August 22 If it was up then someone is in a lot of trouble Quote Link to post Share on other sites
LBD 170 Posted August 22 Share Posted August 22 All this talk about the keel being up being the cause... maybe we leave that speculation for those who understand the GZ moment for this particular vessel. Many shallow draft vessels have the ballast in a small keel or even have the ballast completely inboard such as the Boreals or Koopmans and are designed to still have a great positive righting moment. Some even recomend sailing down wind with sails up and centerboard or keel all or partly raised. I would say keel up for this vessel in this situation is perfectly normal. 2 Quote Link to post Share on other sites
K4309 358 Posted August 22 Share Posted August 22 1 hour ago, Deep Purple said: If it was up then someone is in a lot of trouble I would argue that leaving the keel up at anchor should not result in a 180ft boat sinking in 2minutes flat. If that was the primary cause, then there is a fundamental design flaw, and a fundamental certification flaw. The keel is primarily designed to provide righting moment for sailing, like with the sails up. The boat should be inherently safe with the keel in either position. That said, I'm sure the insurance companies will be crawling all over this, and if the keel was up, the insurance co's lawyers will be asking why, given it was parked in 50m of water. The Captain will need to answer that question. But he may have a defense in pointing to the stability curves and design specs (I've forgotten the proper name for how to make sure a ship is trimmed properly and stable, like when they load ferries and what not). I would expect that, as with all accidents, there were a number of minor and separate issues coming together in a random sequence resulting in the outcome. The old domino theory. One of the guests reported the boat leaning over suddenly then lots of breaking glass, and having to get out of her cabin quickly, over broken glass, cutting her feet etc. The windows on those boats are supposed to be structural components effectively and are definitely not supposed to break. The would have been designed to handle green water coming over them. So if windows have broken, that may explain getting enough water into the boat to sink it. Obviously the question would be why did the windows break? Again, another design and certification question. The boat had a beam of 11.5 m / 38 ft, but more importantly a displacement of 473 tonnes. For it to sink in 2 minutes would need a flowrate of water entering the boat of about 4,000 l/s. There needs to be something fundamentally wrong for that to happen, even with the boat laid over flat. Quote Link to post Share on other sites
Steve Pope 253 Posted August 22 Share Posted August 22 1 hour ago, LBD said: All this talk about the keel being up being the cause... maybe we leave that speculation for those who understand the GZ moment for this particular vessel. Many shallow draft vessels have the ballast in a small keel or even have the ballast completely inboard such as the Boreals or Koopmans and are designed to still have a great positive righting moment. Some even recomend sailing down wind with sails up and centerboard or keel all or partly raised. I would say keel up for this vessel in this situation is perfectly normal. I sail down wind with the main keel up and the aft keel down, at least part way down. Both my boards are alloy and are not part of the ballast which is in the stub keel. Stability isn't a problem, but a water spout or tornado like the one at Westhaven that threw the catamaran over the wharf and almost put a super yachts mast in the water a year or 3 ago would certainly lay me flat at least, no big holes to let the water in though! 2 Quote Link to post Share on other sites
Black Panther 1,701 Posted August 22 Author Share Posted August 22 11 hours ago, K4309 said: For it to sink in 2 minutes would need a flowrate of water entering the boat of about 4,000 l/s. There needs to be something fundamentally wrong for that to happen, even with the boat laid over flat. This. Fascinating? Quote Link to post Share on other sites
Psyche 739 Posted August 22 Share Posted August 22 @chrischamberlaine4160 22 hours ago The Bayesian disaster - in very simple terms for the layperson. This is a one in a million tragedy but we should examine the facts and learn from them. Bayesian boasts the second highest mast in the world at 75 metres on a length of 56m. She has a lifting keel to enable her to get into shallow areas. Fully down it gives a draft of 9.83m and raised a draft of 4m. A sailing yacht has a keel to counter the heeling moment generated by the power of her sail plan. 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. The stability of a yacht has to be sufficient to counter the power of the rig but, as mast heights increase, the keels can often become so deep that the places of interest are restricted hence the lifting keel solution. Stability comes from two factors – the hull form and the ballast keel which acts like a pendulum. As the yacht heels the volume of the immersed section produce a buoyancy force which resists heeling. Initially the keel gives little force but as the angle of heel increases ‘physics’ makes the keel contribution significant. The greater the keel length, the greater the effect. The combination of the hull buoyancy on the heeled side and the keel on the ‘windward’ side produces the force necessary to keep the yacht from capsize. If the keel of Bayesian was retracted it would lose a significant six meters of moment arm or leverage from its probable 200 tons of keel bulb. When we design yachts we calculate the stability, or righting lever, as a function of heeled ‘bouyancy’ force and the ballast moment arm combined. (the GZ) This can be plotted on a graph to show the stability at any heel angle and identifies the angle at which stability becomes negative causing the yacht to capsize. Normally an ocean yacht will experience a negative point at about 120 degrees of heel. With a lifting keel this point is greatly reduced maybe to less than 90 degrees. If Bayesian was at anchor with the keel raised and no sail up the crew would have every confidence that she could remain safe in most normal wind conditions. Every captain at this level has passed an exam on stability and would be aware of his vessels stability graph. Many years ago I sat at Cremorne and watched a spiralling williwaw race across Sydney harbour and pass through Mosman. This twister was only about 30 metres wide but it destroyed houses and overturned cars in its path. A few feet away nothing was harmed. The power of a twister is intense and powerful with the wind is coming from every direction. This was what hit Bayesian. The problem of large rigs is windage, even with no sails. But this yacht had three furling sails forward and a big boom with the weight of a furled mainsail inside all above the centre of gravity. Also there were a few communication domes on the spreaders. We use a wind pressure coefficient to measure the force of the wind on the rig and sails. Even without sails the WPC for Bayesian must have been pretty large when hit by a wind force of varying direction with a local velocity way above the norm. Once she was knocked down beyond her stability limit with the keel up she stood no chance and, laying flat to the water, her deck openings would have allowed a flood of water aboard and she would founder. This would happen in a couple of minutes. The observation of a lightning strike can be discounted because these vessels are grounded and any damage from a strike would have caused a slow sinking at worst – not a capsize and founder. The individuals within a professional crew with sailing experience may have sensed the wind and motion of the vessel and quickly reacted to instinctively save themselves in the seconds they had. My guess is that some were already on deck alarmed by the general conditions.The guests would have found themselves totally disoriented in flooding cabins, in darkness with the walls, doors and passageways at ninety degrees to the norm. They had practically no chance because it would be completely beyond their experience. The crew would have been unable to be of any help due to the speed of the unexpected event. I have been a professional yacht designer and builder for fifty years specialising in lifting keel yachts. My son, a professional navigator, was Third Officer on a ketch superyacht with masts 100m tall; a yacht so big, at 88metres, that it was almost beyond human handling even with the machinery on board. But of course it is the biggest and most expensive’ etc etc. What we have here is a one off accident which is a wake up call to an industry where common sense has departed as yachts get more silly in size and design. All forms of transport have had these one off events which have led to changes of regulations and professional practice. Townsend Thorenson, Boeing, 1955 Le Mans, the 1952 Farnborough crash, the 1979 Fastnet – all have made a difference and they all came unpredicted and out of the blue at a time of complacency. Chris Freer – yacht designer – August 2024 2 6 Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.