Iceberg How much did they need to miss it by


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Jaime Croft Larsen

Guest
Off the top I have to freely admit that I am no expert when it comes to icebergs or ship navigation. Still, in the past month or so I have been reading and watching quite a bit about what we think happened with the Titanic berg, (finally got my "Final Moments" DVD this weekend!), and I've been wondering something...

All discussions/depictions I've seen show the supposed berg as having an underwater spur or shelf that the ship collided with. I've also read a lot that shows that up to 90% of a berg's mass could be underwater. So, I'm wondering, why do all the depictions I've seen show a berg with so little of its underwater mass on the side Titanic struck? Could there not have been much more to the berg on that side, under the water? (I'm thinking of how ice behaves in water and to balance, I would think there would need to be significant mass on all four sides, below the water line, for it to remain stable. Of course, I may have that completely wrong...)

I have to wonder, just how far would they had to have amended their course to actually miss everything? I'm kind of assuming that a berg could be quite dangerous quite a ways away from the portion above surface. I know that bergs are routinely blown up now, but I wonder how current ships estimate how far away to stay. (Likely different routes used now I'm sure ...)

I just find it interesting that nothing I've come across...so far...poses the idea of there being far more mass below the water. The ship always appears to just "brush" the side...

Thanks all - all comments or directions to other threads/info. is greatly appreciated!
 
Dec 3, 2005
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I don't know whether anyone can give an answer to that. We don't really know what the shape of the berg was below the water line. As for it being a brush along the side, it would have actually happened a bit differently because ships don't turn the same way as wheeled vehicles. They rotate into a new direction around their central points and the propellers push them along in the new direction, as is my understanding.
 
Mar 17, 2010
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Also, as the iceberg was in the water and the Titanic was a 'solid object, it would have pushed the iceberg away through the water. It would have to be harder to sink the ship that way. I'd say that it was more of a scrape or something rougher, which caused the rivets to pop etc.

Carla
 
Dec 2, 2000
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Dec 28, 2006
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HOW MUCH DID THEY NEED TO MISS IT BY ?

It is my understanding that the ship rubbed along the berg and that the overlapping plates were parted by the berg pressure causing the rivets to either be forced through the hole in the plate , by the head of the rivet becoming popped off, or a combination of both. I am one of the members who feel that the quality of the steel was to the satisfaction of the experienced and qualified builders, the owners, and the designers.
The pressure incline deflection can only be estimated, my estimate is varying zero to max 20 inches. Can any member correct me ? The answer to the question would appear to be 20 inches. I thank all who provide valid information. GORDON
 
Mar 22, 2003
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>>The pressure incline deflection <<

Not sure what you mean when you say "pressure incline deflection?"

Well most of us would agree that the ship had a near miss. As far completely missing the berg, turning 15 seconds sooner probably would have done it, assuming the berg was not much wider than shown.
135520.gif

135521.gif
 

Jim Currie

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Apr 16, 2008
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Nice sketch Sam!

Are we getting mixed-up with pressure deflection as in clutch plate and centrifugal force? Perhaps we mean what's termed as 'skid' in another forum. i.e. the tendency for the vessel to continue on it's original direction?
As for the plates and rivets - A riveted seam was just a long line of perforations - joined by short lengths of steel plate which was probably stressed round the hole margins during the perforation process. Not the most perfect joining arrangement to withstand a combination of grinding and impact. Sprung rivets were a constant problem throughout the time riveting was used in ship construction. It was even worse for some reason when they used the composite welded seams and riveted butts system during and shortly after WW2. Probably due to the differential in flexing during the ship 'working' in a sea-way. How often do you see the advice 'tear along the line of perforations'?
 

Will C. White

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Apr 18, 2007
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Sounds like what Stanley is talking about is shear-the amount of force applied on the rivet heads as the Titanic scraped past the iceberg. I think he may be talking about applied foot-pounds per square inch along a vector. As to early welded seams, a lot of that was due to bad fluxing and "rod" and as yet un-perfected techniques. Today, the material often fails before the welded seam. WILL
 
Dec 28, 2006
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I was attempting to answer Feb 15 2009 above, the question which is the heading. "How much did they need to miss it by" ?
Pressure inclined deflection being the inclined inward deflection of the plate resulting from the pressure of the ice against the plate. This I estimate at max 20 inches and that therefore would be the distance they needed to miss it by.
GORDON.
 

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