spook Posted April 9, 2015 Share Posted April 9, 2015 That looks like metal fatigue rather than anything else? how old are these parts? doesn't mention when they were last replaced. And yet another self proclaimed, expert, know-it-all. But even more clever - one that can spot metal fatigue from a photo. The Press Release states that these were checked and passed by the regulatory authorities just before coming in to service this year. '. Metal fatigue is difficult to detect until a component that is fatigued enters the tertiary stage when the creep becomes much more obvious. In fact the bigger the lump of metal the more difficult it is to detect without some serious non destructive testing focusing on parts that are suspected of being subject to exceptional load. Ultrasound testing and micro cracking detection is also far from being totally reliable which is why in the case of aircraft and other safety critical applications components are replaced after a period of use based on the established characteristics of the material used and the stresses that it would have experienced over a period of time. What IS a fact is that the surface of a metal component that has experienced a fatigue failure usually shows a particular surface that is irregular and rough. And, 'Silver Surfer', although most of my career did not involve material science, in the early years it did. 1 Quote Link to comment Share on other sites More sharing options...
Silver Surfer Posted April 9, 2015 Share Posted April 9, 2015 That looks like metal fatigue rather than anything else? how old are these parts? doesn't mention when they were last replaced. And yet another self proclaimed, expert, know-it-all. But even more clever - one that can spot metal fatigue from a photo. The Press Release states that these were checked and passed by the regulatory authorities just before coming in to service this year. '. You don't have to be an 'expert' to know metal fatigues with age and stress, I said 'looks like' because that IMO is what it looks like, looking at the top photo of the a frame you can see the deterioration its not clean metal where it has been broken/snapped. I think I would rely on marine authorities, classification societies and ship surveyors to determine condition rather than you. I suspect, as a result, the public would be safer too..... Quote Link to comment Share on other sites More sharing options...
Silver Surfer Posted April 9, 2015 Share Posted April 9, 2015 That looks like metal fatigue rather than anything else? how old are these parts? doesn't mention when they were last replaced. And yet another self proclaimed, expert, know-it-all. But even more clever - one that can spot metal fatigue from a photo. The Press Release states that these were checked and passed by the regulatory authorities just before coming in to service this year. '. Metal fatigue is difficult to detect until a component that is fatigued enters the tertiary stage when the creep becomes much more obvious. In fact the bigger the lump of metal the more difficult it is to detect without some serious non destructive testing focusing on parts that are suspected of being subject to exceptional load. Ultrasound testing and micro cracking detection is also far from being totally reliable which is why in the case of aircraft and other safety critical applications components are replaced after a period of use based on the established characteristics of the material used and the stresses that it would have experienced over a period of time. What IS a fact is that the surface of a metal component that has experienced a fatigue failure usually shows a particular surface that is irregular and rough. And, 'Silver Surfer', although most of my career did not involve material science, in the early years it did. See my post above. I would expect that the professionals responsible for certifying this equipment would be aware of all that. And the chances of two of these (according to the Packet) failing at exactly the same time due to metal fatigue? Pretty slim I'd say. Quote Link to comment Share on other sites More sharing options...
x-in-man Posted April 9, 2015 Share Posted April 9, 2015 (edited) As recent aircraft crashes have demonstrated, ships and planes can be fitted with radar and cameras that can spot a crisp packet floating on, or just below the surface from half a mile away or from several hundred feet in the air travelling at over 100 miles an hour. The water intake on my boat has a strainer.. modern jet powered lifboats have a grill to prevent ingestion of crap, are they telling us this boat travelled 11,000 miles from Tasmania, sailed up and back down the Solent, sat in dry dock being hacked about, then had trials after sailing to Douglas and no one thought .. Hang on, what if we run over a dead cow on the way to Liverpool on day? Nor did it ingest anything other than water and whale piss in all that journey - if that's the case, we could probably walk to Liverpool balancing in all the crap in that little bit of water betwixt here and there. Edited April 9, 2015 by x-in-man Quote Link to comment Share on other sites More sharing options...
NeverAgain Posted April 9, 2015 Share Posted April 9, 2015 I think I would rely on marine authorities, classification societies and ship surveyors to determine condition rather than you. I suspect, as a result, the public would be safer too..... That's understandable, I too would rather trust someone who is paid to do the job than some randomer on the internet. It was only my observation and a thinking out loud style comment as I noticed a couple of things : The metal itself isn't clean, layers of muck as shown on the photo would hide most signs of early metal fatigue, the break itself doesn't look like clean shiny metal, it looks old and pitted. Quote Link to comment Share on other sites More sharing options...
Silver Surfer Posted April 9, 2015 Share Posted April 9, 2015 As recent aircraft crashes have demonstrated, ships and planes can be fitted with radar and cameras that can spot a crisp packet floating on, or just below the surface from half a mile away or from several hundred feet in the air travelling at over 100 miles an hour. The water intake on my boat has a strainer.. modern jet powered lifboats have a grill to prevent ingestion of crap, are they telling us this boat travelled 11,000 miles from Tasmania, sailed up and back down the Solent, sat in dry dock being hacked about, then had trials after sailing to Douglas and no one thought .. hang, what if we run over a dead cow on the way to Liverpool on day? Nor did it ingest anything other than water and whale piss in all that journey - if that's the case, we could probably walk to Liverpool balancing in all the crap in that little bit of water betwixt here and there. Where do they dig you people up from? Do you go on a special course somewhere that convinces you to have an unfailing belief that everything you think of and commit to print must be right? Yes great idea, lets put a 'strainer' over a water jet intake producing thousands of horse power. Now why didn't the manufacturers think of that? Quote Link to comment Share on other sites More sharing options...
spook Posted April 9, 2015 Share Posted April 9, 2015 That looks like metal fatigue rather than anything else? how old are these parts? doesn't mention when they were last replaced. And yet another self proclaimed, expert, know-it-all. But even more clever - one that can spot metal fatigue from a photo. The Press Release states that these were checked and passed by the regulatory authorities just before coming in to service this year. '. Metal fatigue is difficult to detect until a component that is fatigued enters the tertiary stage when the creep becomes much more obvious. In fact the bigger the lump of metal the more difficult it is to detect without some serious non destructive testing focusing on parts that are suspected of being subject to exceptional load. Ultrasound testing and micro cracking detection is also far from being totally reliable which is why in the case of aircraft and other safety critical applications components are replaced after a period of use based on the established characteristics of the material used and the stresses that it would have experienced over a period of time. What IS a fact is that the surface of a metal component that has experienced a fatigue failure usually shows a particular surface that is irregular and rough. And, 'Silver Surfer', although most of my career did not involve material science, in the early years it did. See my post above. I would expect that the professionals responsible for certifying this equipment would be aware of all that. And the chances of two of these (according to the Packet) failing at exactly the same time due to metal fatigue? Pretty slim I'd say. Firstly I would not expect inspection to involve examining other than structural integrity and safety matters. Secondly because the vessels are of roughly the same vintage and having undertaken similar service cycles being exposed to a hazard that the P & O had probably not been exposed to before a similar failure is not outside the bounds of possibility. The bottom line remains that for the route that is being operated it is patently obvious that this class of vessel is unfit for purpose. Quote Link to comment Share on other sites More sharing options...
NeverAgain Posted April 9, 2015 Share Posted April 9, 2015 And the chances of two of these (according to the Packet) failing at exactly the same time due to metal fatigue? Pretty slim I'd say. Judging by the damage I'd say it was almost certainly metal contact on the bottom picture, whether it came into contact with another mechanical part from the boat well I can't say without looking at the official report. Debris is easy to blame but litter/debris normally either sinks or floats on the surface and being a big boat it sits far enough away from both surfaces. I'd be amazed if a filter isn't fitted otherwise every time a jet ski went out it would also break down. Quote Link to comment Share on other sites More sharing options...
spook Posted April 9, 2015 Share Posted April 9, 2015 As recent aircraft crashes have demonstrated, ships and planes can be fitted with radar and cameras that can spot a crisp packet floating on, or just below the surface from half a mile away or from several hundred feet in the air travelling at over 100 miles an hour. The water intake on my boat has a strainer.. modern jet powered lifboats have a grill to prevent ingestion of crap, are they telling us this boat travelled 11,000 miles from Tasmania, sailed up and back down the Solent, sat in dry dock being hacked about, then had trials after sailing to Douglas and no one thought .. hang, what if we run over a dead cow on the way to Liverpool on day? Nor did it ingest anything other than water and whale piss in all that journey - if that's the case, we could probably walk to Liverpool balancing in all the crap in that little bit of water betwixt here and there. Where do they dig you people up from? Do you go on a special course somewhere that convinces you to have an unfailing belief that everything you think of and commit to print must be right? Yes great idea, lets put a 'strainer' over a water jet intake producing thousands of horse power. Now why didn't the manufacturers think of that? Did YOU ever pause to consider that there are a number of people on the Island, and even the occasional interested party who although no longer resident have a deep care about their homeland, that happen to be quite sufficirntly qualified to comment, and even express expert, REAL expert, opinion. A filter of some forms over the intake to the pumps that generate the water jet may be problematic, or might be excessively expensive. I do know that in pumped hydro electric plants in Africa macerating active intakes are used to pump water into the holding lake so the technology does exist though I do not believe that it would be cost effective or technically feasible for a glorified tin bath belting through the water like sh*t off a hot shovel but it's not an idea to be treated as being stupid, rather it deserves an explanation why it is not feasible. Or maybe you don't know why? Quote Link to comment Share on other sites More sharing options...
Silver Surfer Posted April 9, 2015 Share Posted April 9, 2015 As recent aircraft crashes have demonstrated, ships and planes can be fitted with radar and cameras that can spot a crisp packet floating on, or just below the surface from half a mile away or from several hundred feet in the air travelling at over 100 miles an hour. The water intake on my boat has a strainer.. modern jet powered lifboats have a grill to prevent ingestion of crap, are they telling us this boat travelled 11,000 miles from Tasmania, sailed up and back down the Solent, sat in dry dock being hacked about, then had trials after sailing to Douglas and no one thought .. hang, what if we run over a dead cow on the way to Liverpool on day? Nor did it ingest anything other than water and whale piss in all that journey - if that's the case, we could probably walk to Liverpool balancing in all the crap in that little bit of water betwixt here and there. Where do they dig you people up from? Do you go on a special course somewhere that convinces you to have an unfailing belief that everything you think of and commit to print must be right? Yes great idea, lets put a 'strainer' over a water jet intake producing thousands of horse power. Now why didn't the manufacturers think of that? Did YOU ever pause to consider that there are a number of people on the Island, and even the occasional interested party who although no longer resident have a deep care about their homeland, that happen to be quite sufficirntly qualified to comment, and even express expert, REAL expert, opinion. A filter of some forms over the intake to the pumps that generate the water jet may be problematic, or might be excessively expensive. I do know that in pumped hydro electric plants in Africa macerating active intakes are used to pump water into the holding lake so the technology does exist though I do not believe that it would be cost effective or technically feasible for a glorified tin bath belting through the water like sh*t off a hot shovel but it's not an idea to be treated as being stupid, rather it deserves an explanation why it is not feasible. Or maybe you don't know why? I think long and hard before I comment. And I don't hold myself out as offering an expert opinion either. Of course pumps sometimes have filters on. And of course manufacturers of fast craft will have considered this for their ships. The fact that they aren't built with them, and the fact that the safety critical nature of shipping doesn't insist on them tells me that they are either not generally needed, or they don't generally work. I would suspect the latter. Given the sheer power and forces at play I suspect any grill fine enough to still allow sufficient water flow would not last long.... Quote Link to comment Share on other sites More sharing options...
x-in-man Posted April 9, 2015 Share Posted April 9, 2015 A profiled intake grill could probably be designed for craft such as this, returning input levels to the same levels if no such grill was in place. If things where up to Silver Surfer we would all probably still be living in caves and trying to invent the square wheel. 1 Quote Link to comment Share on other sites More sharing options...
NeverAgain Posted April 9, 2015 Share Posted April 9, 2015 Do you go on a special course somewhere that convinces you to have an unfailing belief that everything you think of and commit to print must be right? Not at all, that's why I wrote 'it looks like' which means 'I'm unsure, but it could be a possibility' Quote Link to comment Share on other sites More sharing options...
NeverAgain Posted April 9, 2015 Share Posted April 9, 2015 A profiled intake grill could probably be designed for craft such as this, returning input levels to the same levels if no such grill was in place. Something that wouldn't stop a crisp packet or a coke bottle but would be big enough to stop something like a large fish being ingested. It most likely wouldn't stop fish nets or ropes either but what's the chances of that? Quote Link to comment Share on other sites More sharing options...
Donald Trumps Posted April 9, 2015 Share Posted April 9, 2015 Somewhere out there I think there's a Russian submarine Capt wondering why the Steam Packet keep ramming him 2 Quote Link to comment Share on other sites More sharing options...
Tempus Fugit Posted April 9, 2015 Share Posted April 9, 2015 A profiled intake grill could probably be designed for craft such as this, returning input levels to the same levels if no such grill was in place. If things where up to Silver Surfer we would all probably still be living in caves and trying to invent the square wheel. you only have to have something like a dome shape filter (like on carburettors), or similar idea, so that the area of the holes add up to the original area of the opening so that there is no added restriction to the through flow and have no detrimental effect when fitted except to keep rubbish out Quote Link to comment Share on other sites More sharing options...
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