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Post by herrbrinkmann on Apr 7, 2008 20:43:40 GMT -8
That is correct, we had one broken window and two cracks in the corners of the window and door frame. It is in the area, where the centercasing ends. Suddenly the vessel gets "weaker" at this area and in high seas the ship moves around this point which causes cracks. But as of no waves in her future, there will be no cracks anytime in her life (I hope :-) ).
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D'Elete BC in NJ
Voyager
Dispensing gallons of useless information daily...
Posts: 1,671
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Post by D'Elete BC in NJ on Apr 8, 2008 7:13:11 GMT -8
Markus,
Were you given any information as to the maximum seas she met during her delivery voyage? If so, were they in excess of the maximum allowable wave heights as indicated by FSG?
In any case, as you pointed out, her delivery voyage was likely much more extreme than we can ever expect in her typical service life.
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Post by Dane on Apr 8, 2008 11:10:23 GMT -8
Queen of Chilliwack also suffered very similar damage on her delivery voyage, but it was far more than two windows!!
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Post by queenofcowichan on Apr 8, 2008 16:41:40 GMT -8
Anyone heard when they will start sea tials with her crew?
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FNS
Voyager
The Empire Builder train of yesteryear in HO scale
Posts: 4,948
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Post by FNS on Apr 8, 2008 21:32:52 GMT -8
Queen of Chilliwack also suffered very similar damage on her delivery voyage, but it was far more than two windows!! I think that the TEV PRINCESS MARGUERITE also took a pounding on her delivery voyage from Scotland after reading stories of her. Imagine seeing the eyes of the Panamanians looking at the beautiful ladies of the CPSS passing through their country on their delivery voyages.
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Post by herrbrinkmann on Apr 8, 2008 21:41:50 GMT -8
Markus, Were you given any information as to the maximum seas she met during her delivery voyage? If so, were they in excess of the maximum allowable wave heights as indicated by FSG? In any case, as you pointed out, her delivery voyage was likely much more extreme than we can ever expect in her typical service life. Guessing wave heights from a bridge is a difficult thing. I heard that it was on the limit but the wave length was unfavourable, so it was worse then for the CR. maybe the wave heights where over the limit from time to time - I don´t know. But you are right, never again that high seas...
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Post by Political Incorrectness on Apr 8, 2008 21:59:52 GMT -8
Well I have heard from Scott that repairs are almost complete on the Coastal Inspiration and crew training has begun.
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Post by Hardy on Apr 9, 2008 4:47:48 GMT -8
That is correct, we had one broken window and two cracks in the corners of the window and door frame. It is in the area, where the centercasing ends. Suddenly the vessel gets "weaker" at this area and in high seas the ship moves around this point which causes cracks. But as of no waves in her future, there will be no cracks anytime in her life (I hope :-) ). Picking up on what Markus posted, having windows crack and doorframes crack is a 'good' thing when you look at the over-all design of the ship. It means that it is built strong enough to survive the rough seas, but also that it is built 'soft' enough to flex when it needs to flex. Glass windows don't take well to any kind of flexing and will crack. Same with 90-degree angles on door frames and the like. For any of you that feel thusly inclined, check out the condition of the trans-oceanic cargo ships/freighters that hit the Port of Vancouver - even though most of them have a lot less windows than CR/CI, you will see damage to them from time to time when they port. This is not so much the case with container carriers as it is with other freighters (as with container carriers, they can't take a pounding sea without large risk of losing their deckloaded containers!) In any case, as is also correctly pointed out, the likelihood of significant damage occurring over her regular service life in her anticipated lanes of operation is slim to none, barring accident.
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Post by doctorcad on Apr 9, 2008 7:35:04 GMT -8
I would argue that the areas that fractured at sea represent stress concentrations that will be the first to go when the vessel gets older. As Markus pointed out, the damage was at a transition area where the vessel's stresses are concentrated. Just because the ship won't often see as much stress as it did on its delivery voyage, all the vibrations and loading cycles will cause those areas to rust and crack prematurely. Check out the follwing link to see the kinds of stresses deep sea vessels endure regularly. They are not expected to pop windows or crack door frames from this type of stress: I'm not saying the coastal class ships should be built to endure deep sea conditions, just that the areas identified will be good places to watch. Like a canary in a coal mine...
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Post by Ferryman on Apr 9, 2008 11:06:29 GMT -8
So how would one go about fixing these cracks properly? Would the welder just simply do a carpet weld over the crack, and then sand it down and spray paint it? Or would the section of steel have to be removed all together, and replaced? I'm not an expert on steelwork, but I'm certainly interested, so speak sloooowwwwllly.
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Post by doctorcad on Apr 9, 2008 11:25:57 GMT -8
By the sounds of it the only cracked steel was in a door frame. They would likely just weld it up, as you said Chris.
The concern I was raising is that the vessel has a hard point built-in, as indicated by Markus above. That hard point (at the end of the casing) will concentrate stresses in the surrounding steel and cause it to fatgue more quickly than other areas.
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Post by Alex on Apr 9, 2008 17:02:34 GMT -8
By the sounds of it the only cracked steel was in a door frame. They would likely just weld it up, as you said Chris. The concern I was raising is that the vessel has a hard point built-in, as indicated by Markus above. That hard point (at the end of the casing) will concentrate stresses in the surrounding steel and cause it to fatgue more quickly than other areas. Only if the stresses are high enough to cause a fatigue failure. Remember, as long as the stress is below the fatigue limit for the steel, it can withstand infinite cycles.
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Post by herrbrinkmann on Apr 9, 2008 20:57:32 GMT -8
By the sounds of it the only cracked steel was in a door frame. They would likely just weld it up, as you said Chris. The concern I was raising is that the vessel has a hard point built-in, as indicated by Markus above. That hard point (at the end of the casing) will concentrate stresses in the surrounding steel and cause it to fatgue more quickly than other areas. Only if the stresses are high enough to cause a fatigue failure. Remember, as long as the stress is below the fatigue limit for the steel, it can withstand infinite cycles. Thank you Alex for the absolute correct answers. That is the most important point. If you stay below a certain stress nothing will happen even at sharp corners like doorframes. Only if the stress gets over a certain limit , then fatigue cracks will occur after a while. en.wikipedia.org/wiki/Fatigue_%28material%29Re repairs: In fact you can do both: grind the crack, reweld and smooth it or put an insert plate. you also could do an overlap but this is the cheap and ugly method.
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Post by Hardy on Apr 10, 2008 1:11:37 GMT -8
Not being any kind of steelwork expert, I would also hazard to guess that the cracks and possible future fatigue that we are talking about are indeed at window and door level - ie: in the pax areas at Deck5 and above - ie: the superstructure of the ferry. Everything to do with machinery and engineering spaces and 3-4 more decks above the waterline are unaffected at this point. And as Markus said, it is near the centre casing. I would definitely term this as minor and nothing to be overly concerned about.
Had we somehow managed to develop cracks or stress marks somewhere near, say, oh, the bow/stern door units, then I would be a LOT more concerned. 35+' above the waterline at the bottom of a door jam, and I think that there are probably just some naysayers here trying to pick nits again.
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Post by doctorcad on Apr 10, 2008 7:28:59 GMT -8
Sorry to sound like a naysayer. These are good ships and will last a long time, no question. What I was trying to say was that the area that developed cracks is like a canary in a coal mine, a place to watch for signs in the future.
Take the C Class ships for example. They have problems with corrosion and stress cracking where the casings join the vehicle decks. Most of the C Class ships have insert plates near the doors in these areas.
Also, who is to say that the lcoalized stresses don't approach endurance limit? The reason ship's doors and hatches have radiused corners is to prevent cracking at hard corners. Ships have been lost due to these cracks in the past.
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Post by Alex on Apr 10, 2008 12:23:40 GMT -8
Also, who is to say that the lcoalized stresses don't approach endurance limit? The reason ship's doors and hatches have radiused corners is to prevent cracking at hard corners. Ships have been lost due to these cracks in the past. I would hope the designers of the ship would be able to tell you roughly how much stress would result at those locations during different sea conditions. What with all the fancy software packages these days for such things, it *should be known, although likely with some error. Note also that the design would include a safety factor, and take into account sharp corners (and the numerous other weird ass factors you take into account when doing a fatigue analysis). *I'm just a junior mechanical engineer (recently graduated) with no marine background, so it is possible that there are a whole whack of issues I don't know about that could make determination near impossible, but my instinct tells me I'm at least mostly right.
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Post by doctorcad on Apr 11, 2008 8:02:03 GMT -8
Also, who is to say that the lcoalized stresses don't approach endurance limit? The reason ship's doors and hatches have radiused corners is to prevent cracking at hard corners. Ships have been lost due to these cracks in the past. I would hope the designers of the ship would be able to tell you roughly how much stress would result at those locations during different sea conditions. What with all the fancy software packages these days for such things, it *should be known, although likely with some error. Note also that the design would include a safety factor, and take into account sharp corners (and the numerous other weird ass factors you take into account when doing a fatigue analysis). *I'm just a junior mechanical engineer (recently graduated) with no marine background, so it is possible that there are a whole whack of issues I don't know about that could make determination near impossible, but my instinct tells me I'm at least mostly right. I suspect you are mostly right Alex, and I will stop acting like a know-it-all dick... Lets hope these ships have a long, healthy life on our coast.
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Post by Scott on Apr 15, 2007 13:24:22 GMT -8
We have threads for the other two Super C's, so why not one for the Coastal Inspiration? I'm having a hard time figuring out which one is which... so this will help us keep them separate. Is this the middle one or the last one? It seems BC Ferries is somewhat confused as well since the Coastal Inspiration is apparently being built twice:
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Post by Queen of Vancouver on Apr 15, 2007 14:39:31 GMT -8
Coastal Inspiration is the 2nd ship being built and there is a thread going alredy for this ship.
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Post by Gunny on Apr 15, 2007 15:29:42 GMT -8
The middle child is always the neglected one...
The Middle Child
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Post by Hardy on Apr 15, 2007 16:10:30 GMT -8
The middle child is always the neglected one... The Middle Child Could have been worse though -- it could have been the red-headed step-child in addition to being the middle child ...
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Post by WettCoast on Apr 15, 2007 16:49:14 GMT -8
Quote from BCFS's:
Considering that they have been saying more or less the same thing about the NorAd, are we to believe them this time?
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Post by Low Light Mike on Apr 15, 2007 17:00:02 GMT -8
The middle child is always the neglected one... The Middle Child "Renaissance, Renaissance, Renaissance !!!"
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Post by Scott on Apr 15, 2007 17:11:31 GMT -8
Ah, right. I didn't see the other thread... I just saw the two at the top of the category and figured the other one was missing. Already the neglected child I see:) I'll lock this thread... so any discussion can continue in the original one. My apologies!
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Post by DENelson83 on Apr 12, 2008 13:59:50 GMT -8
So, does anyone know the CI's Canadian callsign yet? I asked previously and got drowned out.
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