NEW YORK and the iceberg same effect


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Jul 14, 2000
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I think it's possible that Titanic's propellers could have actually 'sucked' the iceberg closer to the ship's stern, just as they caused the NEW YORK to break her moorings in Southhampton.

Obviously there is some danger zone associated to Titanic's stern quarter due to the hydrological forces at work back there. Her propellers pulling water through them as they turn would cause strong currents alongside the ship in some fashion. This phenonmenon is seen in the near collision with the NEW YORK upon departure.

These same forces were are at work when the iceberg slipped closely along the starboard side. So the iceberg would feel this 'pull' toward the propellers, and move in that direction as the ship passed. Perhaps this effect is why the iceberg seemed to stay so close alongside the ship, even when the stern was actually swinging away from the berg in a starboard turn.

Yuri
 

Erik Wood

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Not quite,

Titanic was in the middle or in the process of a turn when the iceberg incident took place, there were different forces at play at that moment. Titanic at the time of allision was loosing her momentum as she crossed the underwater shelf. There is a really long explanation for this but I don't have the time today to give it. So hopefully Dave Brown or Parks will pop in here.

Erik
 
Oct 28, 2000
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I'm lurking just around the other iceberg.

One big mistake is to think that the propellers "suck" things toward them with great force. There is a suction current, but it is far weaker than the discharge current. What pulls things into the ship is the Bernoulli effect--which would have been at work between the iceberg and ship.

As Capt. Erik mentions, the Titanic was turning during its interaction with the ice. And, it was slowing down rather rapidly. These movements, and in particularly the deceleration would have reduced the "suction" between the two objects.

With regard to the New York, I think the Titanic's "pressure wave" is what broke the other ship's mooring lines. I'm not sure of the correct term her as I am using my real-life experiences and not a reference book. However, I have noted that the arrival of a large displacement vessel moving rapidly is usually announced in advance by agitation of the vessels docked near shore. This effect is most pronounced in rivers when the current opposes what I call the "pressure wave." The water does not always appear to move, just the docked vessels. In Titanic's case, once New York came free, Mr. Bernoulli got involved.

--David G. Brown
 
Jul 14, 2000
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David or Erik, could either of you tell me how long it takes a large vessel to responde to a 'hard to XXXX' command, if at full speed?

The same question another way is:
Could you avoid hitting an object ahead of you if you had only 30 seconds to make the neccessary turn either way?

The second part of that question is:
How quickly would a large ship begin to loose forward speed, once the command to stop was given?
How quickly if the engines just suddenly lost power? Is there a way to plot that deceleration curve?

Thanks,
Yuri
 

Erik Wood

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The answer to your first question in no. If I have only 30 seconds to react the ship will just begin it's turn. That being said I have been known to use my bow thruster to aid in a hard over turn.

Most ships over 900 feet take about 6 to 7 ship lengths to come close to being stopped. If you throw the engines full astern it is about 2 to 4. Every ship acts differently.

If you just loose power then your screws will continue to turn as long as momentum lets them. Then the ship will continue to glide until the all of momentum from behind the ship is gone.

I am sure somebody else could do a better job of explaining it.

Erik
 
Oct 28, 2000
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Yuri-- let me change the direction of thought slightly. The time needed for Titanic to turn or stop may not be relevant to the discussion. The reason is that the time needed for either or both maneuvers may well have exceeded the time between final warning and impact.

Before worrying about how quickly the engineers could have "crashed back" the engines...or long it took for the ship to rotate two points...we first need to determine the time duration from the instant that Murdoch first realized the situation until steel first met the ice.

For 90 years historians have followed the BOT approach of assuming that the ship's head rotated 2 points (22.5 degrees) prior to contact. Tests with Olympic showed that took 37 seconds or so. Thus, that became the "set in concrete" time between warning and accident. However, that whole scenario is based completely on Hichens' testimony which is at odds with several other members of the crew. In other words, the 37 seconds is not necessarily the truth any more than "No Pope" or the mummy.

I am currently exploring what happened between 11:30 p.m. and 11:40 p.m. How did an iceberg get in front of Titanic at such a short range that it could not be avoided? The accepted answers are all mystical explanations involving "one in a million" weather conditions, etc. So far, all of my answers have come in the form of new questions--but the hunt goes on.

-- David G. Brown
 

Erik Wood

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I have been hunting for this very answer for several years. Maybe you will come close, or maybe you already are.

Erik
 

Don Tweed

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Fate? No. Mystical? Yes.
This is a great topic Eric, David and Yuri.
I to am former Navy, though not as distinguished a career as yours Eric.
We know of the lack of binoculars, and no waves breaking at the base of the berg, etc.
Maybe that is why we are all colectively obsessed with the Titanic.
The lack of difinitive answers to our questions makes us that much more exhasperated in our quest for the truth.
She takes on a mystical place in our hearts and minds for the simple lack of answers.

Just my opinion, Don

P.S.- I am going to keep looking for the answers!
That last ten minutes, wish I could be more informative David!!!
 
S

sue cooper

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"The lack of difinitive answers to our questions makes us that much more exhasperated in our quest for the truth.
She takes on a mystical place in our hearts and minds for the simple lack of answers".

Well put, Don. I share your feelings.

Sue
 
Sep 12, 2000
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To anyone who wishes.

Many moons ago, there was a thread I started about the Bernoulli effect. Got some interesting comments. I have no idea where that thread is now as it was before at least two thousand site modifications.

But I was interested in the concept of the "pressure wave" Dave Brown mentioned above. So I thought he and others may be interested in the following.

Not a seaman, but just an interesting point here the book The Last Days of the Titanic by E. E. O' Donnell page 55 contains a rather large photograph between New York and Titanic and if you look closely you can actually see the way the water is churning due to the two ships being drawn to each other and the forces between them.

If you have this book Dave, is this caused by the Bernoulli effect, plus a pressure wave and that the depth of the harbour contributed to this as well?

You can give me the Titanic Easy Reader version if you wish.

Maureen.
 
Oct 28, 2000
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Maureen -- Let me start out by displaying my non-credentials as a hydraulic engineer. I have never claimed to have engineering training in these matters, just limited practical experience.

My "pressure wave" suggestion is drawn from real-life observations. And, I understand this pressure wave goes downward as well--and can be used to explode infernal devices called "mines." I suspect that the pressure wave from Titanic caused New York to break free. After that, it was a combination of local current, Bernoulli effect and windage that created incident. When Titanic reversed one engine, the prop wash coupled with the slowing of the big ship allowed the tugs to get things under control...or at least that's the conventional story.

However, I'm wondering...did anyone look up?

The relative shallow depth would also have played a role. Anyone who has worked the "Western Rivers" of the U.S. knows that the shallow depth causes towboat wakes to take on the appearance of a tidal bore. Boats along shore will actually dry out as the river disappears...then it comes back in an overfall that can be more than a tad dangerous.

For those who are not in the towboat profession, the term "Western Rivers" refers to the Mississippi River and its tributaries. It goes back to pre American Civil War days when the Mississippi was the western boundary of the country.

But, I digress (as usual).

The interaction between ships is substantial. I have seen a freighter work out of the upper lock of the Welland Canal (goes around Niagara Falls) at less than an old man's walk. The reason was to avoid pulling another ship off the wall. This other ship was waiting to enter the lock. Once the downbound vessel was past and clear, it speeded up to the canal limit of 8 knots. Until then, they were "ticking" over the big diesel at about 20 cylinder detonations a minute--you could hear each one.

To me, both the New York and the Hawke incidents indicate the depth of the lack of understanding that existed in 1911-12 regarding the big ships then being built. I don't see Captain Smith as the sole focuse of this lack of knowledge. He was probably more of an expert than most mariners. We have to recall that most of our knowledge of things like Bernoulli's Principal come from aeronautics--which was an infant science in those days.

-- David G. Brown
 
Jul 14, 2000
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Sorry for taking so long to get back to this conversation. Its been a busy weekend for me.

This is going to be a long post, so be warned.

Time, speed, and distance

Ok, I did some calculations and I came up with something interesting, regarding Titanic's speed and the time needed for some important things to take place.

Titanic was traveling at 22 knots, or about 25 MPH. Which works out to be close to 2228 feet per minute, or 37 feet per second.
So Titanic would travel forward its own length (882 feet),in only 24 seconds.

This means that the iceberg would have traveled from stem to stern in 24 seconds, assuming no significant loss of forward speed on the part of Titanic.

<font color="aa00aa">24 seconds.

Now for a group exercise, everyone please look at your watches and observe how long 24 seconds takes to pass.

...Ok, done? Good. Keep that perception of time in mind as we go forward.

Now lets deconstruct those critical 24 seconds. First, how long did it take for the iceberg to do its fatal work? Well, if we accept that the damage to Titanic was limited to what has been commonly reported along the starboard side of the hull, then we have damage to the first 6 compartments. All the way from stem back to boiler room 5, some 270 feet give or take.
So as the Titanic would have passed the iceberg going 37 feet per second, the damage would have occurred in the first 7 to 7.5 seconds of contact.

Now repeat the exercise with your watches. This time notice only 7 to 8 seconds.

...not long is it?

So of the 24 seconds needed to pass the iceberg, after 7 seconds the damage was done and the berg is passing aft of the forward funnel.
Continuing along the starboard side:
At 8 seconds, it passes the 1st class entrance on D deck.

At 9 seconds, it passes the entrance to the gym on the boat deck.

At 10 seconds, it passes 2nd funnel.

11 seconds: its almost directly amidships.
12 seconds: it passes the 1st class lounge.
13 seconds: it passes the 3rd funnel.
14 seconds: it passes the Aft Grand Staircase.
15 seconds: it's just along the engine room.
16 seconds: its outside the turbine engine room.
17 seconds: it passes the last funnel.
18 seconds: it passes the 2nd class stairs.
19 seconds: it passes the 3rd class entrance on E deck.
20 seconds: it passes the stern mast.
21 seconds: its along the aft well deck.
22 seconds: it passes the last set of cranes.
23 seconds: it passes QM. Rowe on the stern bridge.
24 seconds: it passes the stern railing and dissapears into oblivion.

Time to turn.

How could Titanic react to a 'hard-a-port' command after impact in less than 24 seconds?

Hichens would have to turn the wheel from one extreme position to the other. (4 sec.??)
The steering gears would have to receive that change and respond. (another 2 sec.?)
The rudder would have to swing from one side all the way over to the other. (another 2 sec.??)
And the force of the water against the rudder would have to stop the momentum of the original turn to port, which would swing the stern to starboard, then begin to push the stern back to port. (5-6 seconds ??)

How long would all of that take? I'm just guessing, but maybe 12 - 14 seconds at least.
The tests of Olympics turn rate determined that it took 37 seconds to turn 2 points to port. So I think my guess above is in the ballpark for how long it might have taken for Titanic's rudder to go from full turn to port, to full turn to starboard. I think that 10 seconds is about the lower limit for the fastest time needed to make such a manuever. So assuming all my estimates above on time are incorrect, then lets say that the change could take no less than 10 seconds to complete.

Given that, then if the 'hard-a-port' command was made after impact, the ship's reaction would have to begin when the iceberg was already almost amidship. Well aft of the damaged area forward.
So if the 'hard-a-port' command wasn't what stopped the damage to Titanic from continuing further aft, then why did it stop?

So what stopped the iceberg damage?

If the 'hard-a-port' command didn't really begin to pivot the stern away from the berg until it was almost amidships, then what caused the berg to move out of contact with the side of the ship? Answer: Nothing.
With the ship turning to port, the stern was swinging out to starboard, or toward the berg. So the berg should have remained in contact with the side of the ship for the full 24 seconds, causing more damage along the way. But that didn't happen. The damaged only continued aft for 270 feet, then it stopped.
The only explination of this is that the ship was already turning to starboard within the first few seconds of impact. Meaning the command 'hard-a-port' was given several seconds earlier, or more precisly, a few seconds before impact.

This is not a new idea, just ask Dave Brown, or Parks, or any other experienced board memeber here. I bring up the argument of the 'hard-a-port' command being given before impact in order to show more clearly why I think the iceberg was 'sucked' or drawn toward Titanic.

<font color="ff6000">Mr. ROWE. It was so near that I thought it was going to strike the bridge.

Quartermaster Rowe was stationed on the stern of Titanic. The iceberg would have passed by him 23 seconds after it first impacted the forward bow. Since the ship was already turning to starboard in response to the 'hard-a-port' command, the iceberg should now be moving further away from the side of Titanic. But QM Rowe clearly testifies that the iceberg was still only a few feet away from the side of the ship.

Again, 24 seconds:
After 7 seconds, the ship had turned enough to starboard to put some distance between the berg and the hull. That leaves 16 seconds of turning to starboard before the berg passed QM Rowe on the stern. So why is the ice still so close?
Shouldn't it be farther from the hull by then? The stern is swinging out to port, away from the berg. Why is the berg clinging so close to the ship? Answer: The Phenomenon.

The only reason that the ice was still so close to Titanic, even as the ship was moving away from it, is that some kind of current in the water near the stern, or other hydro-dynamic force caused by the propellers, or the ship's displacement, created a 'pull' on the berg which drew it nearer as the ship passed by.

The evidence is there for comparison. The Hawke, and the New York were both examples of this phenomenon. Floating bodies that are caught up by some force produced by close proximity to Titanic's stern. Is it suction from the props? Or a trough and wave of water caused by Titanic's size? Physicists will have to figure that one out.

But it seems clear to me that the incident with the NEW YORK in Southampton, and the iceberg seeming to remain right alongside Titanic's stern are related to a common effect.

Yuri
 
Oct 28, 2000
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Yuri -- your analysis requires a careful response, which I cannot give as I am currently on deadline for my new book. However, you have not considered the effect of friction upon both the rotation of the ship and its speed. Titanic markedly lost momentum on the ice at the same time as asymmetrical drag was trying to turn the ship to the right.

You are correct in saying that Bernoulli suction would have continued throughout the event. And, the attraction would normally be stronger at the stern than the bow. This force is erroneously attributed to propeller suction, but is really the dynamics of the ship itself. I believe that Titanic remained close to the berg...and may have gotten a wee bit closer toward the stern...as the ship passed. However, close is not a cigar in this case. The only thing that counted was damage to the integrity of the hull--and that did not occur. This indicates the amount of rudder was sufficient to keep the stern clear.

I would feel a lot more comfortable with Murdoch ordering "hard a-port" to turn the ship right--toward the iceberg--a few seconds prior to impact. However, QM Olliver is quite specific about the order of events. He says that he felt the ship strike and then heard the helm order.

Back to the speed of the event. Assuming that Titanic decellerated, it would have done so mostly during the period of time while the ice moved from forefoot to bridge, which is near enough to 300 feet as makes no difference. That's 1/3 of the ship. After that, the hull seems to be free of the ice in any meanigful way.

Assume Titanic lost about 1/3 of its way on the ice. The berg is now moving past the ship at an apparent speed of only 25 feet per second, which allows 23+ seconds for the rudder to "bite" and move the stern away.

There is a phenomenon which I am trying to investigate with regard to the calving of icebergs. The nature of the phenomenon could account for ice on the well deck and the quite strange impact with the topsides in way of the well deck that produced no sideways jerk of the deck, as would be expected. If what I have found is true--and I don't know yet one way or the other--the ship may need not have come close to the portion of the berg that showed above the waterline. For those who want to look into obscure references, you will find this in the 1824 edition of Captain William E. Parry's expedition to the North-West Passage (Published by the Authority of the Lords Commissioners of the Admiralty). Check the definition of "calving."

-- David G. Brown
 
Sep 12, 2000
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Dear Dave Brown,

Thanks for your answer.

But take it a little different, the "seen" iceberg is only 1/7 of the total thing that is there. So what if the ice berg did have an ice shelf to it that was submerged and did a C-shape that curved outward towards the ship, but actually came around the bottom of the ship.

Would the "pressure wave" and the "shallow depth" with a sort of Bernoulli effect cause a similar effect on the iceberg as New York and Hawke?

Just as the slowing speed caused the release of the New York, the slowing speed released the berg but gave it a morse look to the damage. And that is why the ship was released from the berg at the stern (due to its much slower speed)?

And since you addressed your response to me I just wish to make it clear that I never said that they had this information in 1912 or that Smith should have known this. I for one am not addressing the people, only the ship and what happened as the possibilities.

So this was value added: "To me, both the New York and the Hawke incidents indicate the depth of the lack of understanding that existed in 1911-12 regarding the big ships then being built. I don't see Captain Smith as the sole focuse of this lack of knowledge. He was probably more of an expert than most mariners. We have to recall that most of our knowledge of things like Bernoulli's Principal come from aeronautics--which was an infant science in those days."

Maureen.
 
Jul 9, 2000
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Yuri, by chance are you planning on coming to the gathering in Topeka that Erik Wood is planning for September? Seems to me you've been doing some homework here which would give a lot of us some food for thought.

Understanding the dynamics of the collision itself seems a rather complicated affair, but it looks like you're making the effort. FWIW, I suspect what happened in general terms is a bit simpler then some might imagine.

1)Murdoch saw the berg
2)Murdoch tried to avoid the thing with the port around manuever
3)The Titanic struck ice because she came about to starboard just a few seconds too soon, essentially turning into the damned thing, but sliding off as she was carried forward by her own momentum.
4)Everybody's night is ruined.

Of course, the devil is always in the details, so please keep it up. I'd be interested to hear more of what you have to say.

Cordially,
Michael H. Standart
 
Oct 28, 2000
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Psst--don't tell my editor that I dropped in here to "decompress" from the last-minute fact checking on my new book. The people at the publisher think I've been working all weekend.

Quickly, we can speculate about the interaction between the ship and iceberg, but never know exactly because so much critical data is missing. For instance, we don't know how fast Titanic was really going. The numbers favor 22.25 knots--but there is no proof that this was the actual number. Don't forget several passengers thought the engines speeded up sometime between 10:15 and 10:45 p.m. (or thereabouts).

What we can say is that the shape of North Atlantic icebergs almost demands a "grounding" type of accident and not the classic sideswipe. And, during that type of accident there would have been all sorts of forces--hydraulic and otherwise--involved.

Bernoulli effect suction is probably the easiest to understand. Left unopposed, it would bring the side of Titanic into ever closer contact. We can speculate that the damage would have continued all the way along the starboard side. If the ship were under starboard helm (turning left in 1912) as Hichens claimed, the outward "kick" of the stern toward the berg would have been augmented by the Bernoulli effect and who knows how much damage would have resulted.

Of course, under right rudder (port helm in 1912) there would be a counter force created to pivot the stern away. However great or small these opposing forces might have been, we can say that it appears the rudder won the battle because Titanic lost meaningful contact with the ice somewhere about funnel #1.

Bernoulli effect most assuredly does work between a vessel and the bottom. My tiny riverboat would gain up to 6 inches of draft when running at high speeds in extremely shallow water. This effect is often called "squat." The grounding of QE2 a few years ago has been attributed to the ship traveling at too high a speed for the depth of the water. From what I have read, QE2's draft was less that the depth, so an accident seems impossible. But, she was "squatting" deeper because of the shallow water and that was enough to make things go bump.

Before anyone else points it out, part of QE2's problem also had to do with trying to drive a displacement hull at high speeds. In effect, the ship digs a hole by trying to climb on top of its own bow wave. For those with toooooo much time on their hands, a displacement hull can only go 1.34 x sq rt of its waterline length. That's why ships had to get longer and not wider for higher speed.

The hydraulic forces involved in the accident were minor in comparison to the ordinary Newtonian physics of driving 50,000-odd tons of steel over a multi-million ton chunk of ice. I have never believed that the only damage to the fragile part of that equation--the ship-- was a paultry 12 square feet of opening in the shell plate.

(Capt. Erik-- are you there?)

Once I survive the "White Hurricane," I plan to get back to the paper that I've been concocting that covers the last 10 minutes of normalcy aboard Titanic. I have always been fascinated as to how something the size of an iceberg managed to get in front of the ship without being noticed. And, the more research that I do, the more I become convinced that Titanic ran over an iceberg because nobody was "driving."

As usual, I digress.

-- David G. Brown
 
Jul 9, 2000
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Adam, check the "Let's Meet" Folder for the Technical Event in Topeka. Erik announced the event almost a month ago. I already have my holiday time approved, so I plan to be there.

Cordially,
Michael H. Standart
 

Erik Wood

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Aug 24, 2000
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Things have been extremely busy for me so I am now just getting back to the board. Let me start by saying that there has been a lot of talk here. Good to see, especially on this topic. Let me start by saying that mathamatical calculations are great when you have have offical distances to go off of.

We are not exactly sure how far away the berg was when it was sighted nor are we sure of how quickly Murdoch reacted. Because of some research done by Nate Robinson, Dave Brown and myself I think I can say with relative certainty that no "hard a starboard" order was offically given. Which then means that the "hard to port" order was given just after the bottom touched the ice shelf. The reason I say this is if it looked as though the ship would pass it, he wouldn't have done anything, but if he felt her touch then he knew he had to stop damage. That was the sole purpose of the hard to port manuver.

Dave and I have been going round and round about the speed issue. I think what it boils down to is that regardless of Titanic's speed that night she was going to fast. Physics and the nature of the grounding had pretty much taken away 90% of Titanics forward momentum by the time she was off the berg.

This being said there is more then one reason as to why the ship spun around the berg so rapidly. You must remember that the starboard side is what touched. The second the bottom started to run across the shelf the ship lost forward momentum which meant that the momentum from the right prop was starting to loose it's affect. The port prop was actually aiding in the port round as was the helm. Much like how split screw ships dock now days.

The effect of suction doesn't really apply here in the way I think it is being suggesed. For one the ship was actually in contact with the object. As the hull came off the shelf there was no doubt some suction was there, but the nature of the grounding in combination with the helm order and the ships direction was pushing the stern clear of the berg. We know that there was no iceberg damage aft of Boiler Room 5 which means that the ship was able to stay away from the berg past this point. The distance really doesn't matter 2 inches or 20 feet.

Also in relation to suction you have to remeber that Titanic had lost a good majority of her momentum. The majority of Titanics momentum was still being carried by the port side. Remeber that as I stated above the port side (including the prop) had unchecked momentum.

Ships are really split into two sections: what is left of the center line and what is right of the center line. What was right of the center line suffered the majority of damage, while the left side of the center line continued on as if nothing was wrong.

As to grounding I am leary in comparing Titanic with the QE2 for one simple reason. Titanic was a riveted ship and the QE2 was welded. The damage done to Titanic would be much worse because of her construction, but the fact she stayed afloat after suffering what she did says alot about her construction. I am currently doing some research into a grounding the Aquitania suffered in 1919. The damage done there plagued her for the rest of her career. Those who come to Topeka will see my written paper on the subject.

Most groundings demolish internal workings and the ship for the most part stays dry. They may loose a tank or two but dry. Titanic was not so lucky. The grounding forces where enhanced by the loss of momentum and the fact the ship floated free. Once you add water into the mix the ship is done for.

Now I am going to throw some meat to the wolves. This is something that will be discussed at length in Topeka in September.

"Titanic would have sank if she had suffered the same grounding damage but water was confined to entry into Cargo Hold 3. Water only entering in one compartment at a uncontrollable rate"

What do you all say to that?? If you want more you will have to come to Topeka. Remeber that this is a working theory so don't hang me yet.

Erik
 
Jul 14, 2000
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Thanks for the invitiation Michael. It would be an honor to join the event.

There are a couple of things I'd like to point out about the collision dynamic between Titanic and the iceberg.
First, its my opinion that the shape of the iceberg has been greatly misunderstood. I'm no mariner, but when I look at the traditional example of the iceberg that sank Titanic, it doesn't look right to me:

<table border=1>[tr][td]
attachment_icon.gif
Traditional
Iceberg1.bmp (33.6 k)[/td][/tr][/table]​

Notice the vertical column shape. Very narrow, and floating with only the top crown exposed above water. But this just isn't how ice floats! Take any glass of water and pour in some ice cubes to see it for yourself. Ice doesn't float in a vertical column. It seeks horizontal stability.


****CONTINUED IN NEXT POST*******
 
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