Topic: You were REAL close, Vstep, but not quite.... (Read 30749 times)

RMS Gigantic · « **on:** January 18, 2009, 05:01:37 »

I'm back with Titanic's sea trial data, but this time around, I'm using another source: "1912 Facts About Titanic: Revised Edition"

This time, the data is more precise, in feet, rather than yards.

Now then, first things first: her "crash stop" distance. For those who do not know what a crash stop is, that's where the engines are slammed into full reverse when the ship is traveling ahead; it's an emergency stop that normally would never be tried again for the potential of seriously damaging the engines.

Doing this from 20 knots, according to the book, it took 2,550 feet, or 850 yards (same figure from before, wouldn't you know!) to come to a complete stop. They also gave this figure as "just short of three times the length of the ship itself."

With the figure of how many ship lengths given (2.8887000849617672047578589634664 times according to the math), I went into the mission editor to see if the game matches the figures. I managed to get a big bouy right where she is traveling at 19.__ knots, about to reach 20. I then lined up 3 Titanics after that point. I hit full reverse as soon as the bow of the ship was at the close end of the bouy. As you can see by the picture, despite traveling at less than 20 knots when the engines were put into reverse, she traveled nearly 4 of her own lengths before coming to rest. in the first run, I failed to get pictures because she started going backwards a bit before any could be taken, so I did it a second time to show the results. Both runs yielded the same result in terms of stopping distance.

In the first picture, that black pixel next to the back most Titanic is the buoy I reversed at, the bow of the front most Titanic in line is the point before which she was SUPPOSED to stop, and the bow of the Titanic not in line is where she DID stop. the second picture shows just how far past the 3rd Titanic she was before stopping completely. The Titanic in the forground is the player Titanic being tested.

In closing, I have this to say:

You were close, Vstep, REAL close, just one ship length off....

PS: before anyone accuses me of this, it's not that I don't want any other vessels corrected. I would love to see all the vessels as accurate as possible. The reason that I don't talk about them is I don't KNOW about those vessels, so I don't know what their problems are!

Agent|Austin · « **Reply #1 on:** January 18, 2009, 05:09:42 »

why does stopping distance have to be so precise? Is it just not good enough if it takes a little longer to stop?

RMS Gigantic · « **Reply #2 on:** January 18, 2009, 05:14:07 »

Quote from: Agent|Austin on January 18, 2009, 05:09:42

why does stopping distance have to be so precise? Is it just not good enough if it takes a little longer to stop?

The closer it is to the real thing, the more accurate, true? I could have sworn this board was made to help Vstep get the game as realistic as possible. I thought they said they wanted sea trial info?

Agent|Austin · « **Reply #3 on:** January 18, 2009, 05:15:51 »

If you say so

RMS Gigantic · « **Reply #4 on:** January 18, 2009, 05:20:23 »

I'm just lucky I didn't go with my first idea for testing it:

Going with Sea Trial data and lining up 3 Titanics, then putting a big ship after it that Titanic would hit if it turned out the game was off.

That would have been bad....

So it COULD prove useful, as one ship length could be the difference between a near miss and a really bad collision that she should have been able to avoid!

Mad_Fred · « **Reply #5 on:** January 18, 2009, 05:24:57 »

Could be usefull.. but can the book be proven correct? That would be important.

Because..AFAIK the 'real' data is allready used, from what I have understood in the past.

But if that source is wrong, and it can be scientifically proven, it would be valuable.

Regards,
Fred

RMS Gigantic · « **Reply #6 on:** January 18, 2009, 05:29:20 »

I was thinking the same thing. When I discussed the data with you before, you said titanic-titanic.com could very well be wrong.

All I know is this is the second source to give 2,550 feet as the distance.

Perhaps missing a few RPM on her perpellers, as mentioned before, could be part of this difference in crash stopping distance?

You could try to contact the book's author, Lee W. Merideth, to ask about his source(s), perhaps?

Agent|Austin · « **Reply #7 on:** January 18, 2009, 05:33:03 »

The missing RPM could be the culprit, you may have found the answers too all our questions... Lol.

RMS Gigantic · « **Reply #8 on:** January 18, 2009, 05:37:39 »

Indeed, she traveled 2 or so knots faster in real life than in the game, so who's to say her reverse speed wasn't under estimated, too?

Mad_Fred · « **Reply #9 on:** January 18, 2009, 05:51:27 »

Quote from: RMS Gigantic on January 18, 2009, 05:29:20

You could try to contact the book's author, Lee W. Merideth, to ask about his source(s), perhaps?

Aren't those usually listen in the book itself? Is there such an index in it perhaps?

RMS Gigantic · « **Reply #10 on:** January 18, 2009, 06:05:47 »

The bibliography is provided, but he does not specifically state what came from where.

Mad_Fred · « **Reply #11 on:** January 18, 2009, 06:46:41 »

Righto. Logical too.. It would take yet another book to describe which of all the specific bits of this book come from what bits of which other books, I reckon.

RMS Gigantic · « **Reply #12 on:** January 18, 2009, 07:06:22 »

So I take it contacting the author is the best thing we can do?

By the way, I am currently about to test Titanic's turning diameter. The books gives it as "about 3,850 feet, which is 1,283 yards or about 4Â½ lengths of the ship." (Different from titanic-titanic.com this time!) It says it did this after traveling at 20 knots in a straight line.

RMS Gigantic · « **Reply #13 on:** January 18, 2009, 07:38:29 »

Got the results!

I also found the reason why we can never quite recreate the 1912 collision!

If my sources are accurate...

TITANIC'S TURNING DIAMETER WAS CONSIDERABLY UNDERESTIMATED

I moved the buoy further from Titanic in order to give her a bit more time to reach a higher speed.

I then turned the wheel to port as far as possible (540 degrees on the wheel, 45 on the rudder) once she passed the big buoy (in front of the front most Titanic in the pictures); the results were disasterous. They were pictured, and can be seen attached to this post. It turns out what SHOULD be Titanic's turning RADIUS is her turning DIAMETER in game, as what should be 4Â½ ships comes out to be 2Â½ in game.

Season · « **Reply #14 on:** January 18, 2009, 08:55:05 »

Quote from: Agent|Austin on January 18, 2009, 05:09:42

why does stopping distance have to be so precise? Is it just not good enough if it takes a little longer to stop?

Agree. In Dutch we call this "mierenneuken". No offense $:-\$

RMS Gigantic · « **Reply #15 on:** January 18, 2009, 09:47:54 »

Quote from: Season on January 18, 2009, 08:55:05

Agree. In Dutch we call this "mierenneuken". No offense $:-\$

2 reasons:

1) It may be a single ship length, but we ARE talking about the 4th largest ship in the game here!

2) Titanic SHOULD have been able to stop in time to avoid the collision in the attached pictures, and while that was set up, consider this scenario:

You are piloting Titanic in MP through a channel in Marseille, when suddenly someone cuts you off in who knows what! You throw the engines in full reverse, yet still can not stop in time, and you hit them at just over a single knot, which damages you enough to sink you. Would you not be even SLIGHTLY annoyed by the fact that you SHOULD have been able to stop in time?

mvsmith · « **Reply #16 on:** January 18, 2009, 09:51:44 »

Any tests on Titanic in the simulator need to be carefully conducted and interpreted.
Do the screws on the model take as long to go from ahead to full reverse as it takes the massive reciprocating engines?

Does the rudder on the model take a full 30 seconds to go from amidships to hard over?

It is possible to read stopping distances directly from the HUD rather than use the very crude unit of â€œship lengthâ€.

RMSG has demonstrated an inability to properly evaluate and interpret a document that he has used to support an argument, while that document did just the opposite. I would take with a cup of salt any material he cites as an authority unless its information can be traced directly back to the Harland & Wolff archives, which are publicly available.

I find it amusing that he should be such a stickler for accuracy in the simulator, yet cling so desperately to thoroughly discredited myths.

RMS Gigantic · « **Reply #17 on:** January 18, 2009, 09:53:43 »

If I'm so incompitent, then YOU do it!

mvsmith · « **Reply #18 on:** January 18, 2009, 09:56:54 »

Quote from: RMS Gigantic on January 18, 2009, 05:01:37

I'm back with Titanic's sea trial data, but this time around, I'm using another source: "1912 Facts About Titanic: Revised Edition"

This time, the data is more precise, in feet, rather than yards.

How can the data in feet be more precise if the original measurements were taken in yards?

Shipaddict · « **Reply #19 on:** January 18, 2009, 10:00:13 »

How about RMS Gigantic, that VSTEP invite you to do ALL the work on Titanic. You can go through all the code for it and make "improvments".

Then release and we wil all come and have a lovely long moan about how you made the mast colour the wrong type of brown and how she turns to fast.

TerryRussell · « **Reply #20 on:** January 18, 2009, 10:04:31 »

The problem is that this is all based on partial data. As Marty has said, you need to factor in other data. The vessel could not simply go from full ahead to full astern in an instant. Even if it did, the cavitation effects would mean that the reverse thrust would be negligible until the forward velocity reduced to a certain level.

After that....

And so it goes on. You do need ALL of that data before you can claim that something would or should have happened.

The problem is that so many sources of data merely come from other sources. If the source was not reliable, all subsequent usage is unreliable. Most of the "facts" around Titanic, even the manufacturer's data, do not seem reliable.

The fact that it is in a book, or that the book quotes a reference does not make the data any more reliable.

By the way, I was in Borders (Bookshop) yesterday. They had a book which contains the transcripts of the Board of Investigation proceedings. That will no doubt contain the statements of survivors, the ship designers and builders and so on. Many of them will have been trying to prove that the disaster was not their fault. So the data there will not be reliable, I suspect.

No, I didn't buy the book. I almost dozed off when I saw the title.

mvsmith · « **Reply #21 on:** January 18, 2009, 10:04:58 »

Quote from: RMS Gigantic on January 18, 2009, 09:53:43

If I'm so incompitent, then YOU do it!

â€œIncompetentâ€ is your self evaluation.
I have no interest in doing what can best be left to the dynamics team.

RMS Gigantic · « **Reply #22 on:** January 18, 2009, 10:12:33 »

Well, where do you people suppose I get my information, then? I turn 16 in two days and live in the US, so I can't just march right up to the Board of Trade or Harland & Wolff and ask for what Francis Carruthers documented on April 2, 1912!

TerryRussell · « **Reply #23 on:** January 18, 2009, 12:31:51 »

I don't think anyone is suggesting that you get any information, only that you shouldn't believe that all things stated in books are correct.

The problem is that when you say "X is wrong, because I've read/been told Y", unless you have indisputable sources of information, someone will be able to successfuly dispute it (by definition).

100 years on, there are very few indisputable sources of Titanic information except it was a ship that hit an iceberg and sank, drowning a lot of people in the process.

IRI5HJ4CK · « **Reply #24 on:** January 18, 2009, 12:50:22 »

......Another Titanic topic....I think we are all getting very bored now RMS....dosen't look like any lessons were learnt after the last topic you made on Titanic

We all have our favourites, my favourite's are Furie and Sherpa, I could say that the Sherpa's wheelhouse isn't correct, this that or the other, but I'm happy the way she is, and I think you should appreciate the good job V-STEP have done on Titanic. Also, where are all these sources coming from? We will never know exactly, like Terry said, Titanic sank, and thats it really. Be happy with what you have.....

Jack.

Author Topic: You were REAL close, Vstep, but not quite.... (Read 30749 times)

mvsmith

mvsmith

TerryRussell

mvsmith

TerryRussell