2006 MMA Simulation


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Oct 28, 2000
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Everyone--

Over the next few day's I will attempt to summarize the accident simulations we ran on the Maine Maritime Academy's ship bridge simulator. The information will be posted as quickly as my work schedule allows. I welcome questions, but keep 'em simple so as not to embarrass me.

Quick summary -- It is impossible to steer around an iceberg using any of the traditional scenarios. This is true whether the berg is on centerline or shifted well to starboard. I believe that our simulations have put to rest any thought of a "hard over" ice-avoidance maneuver.

Surprise Revelation-- Two students, Cody Libby and Matt Patnaude, found a way to get round the berg using a maneuver closely related to the alleged "port around," but their method was in no way the actions that Boxhall and Hichens claimed Murdoch ordered.

Libby and Patnaude got around the berg by NOT using a hard-over rudder. And, the other simulations conclusively proved that using a "hard a-starboard" command (or the opposite) would have prevented the ship from deviating course rapidly enough.

We gave the students a 50-second advance warning. Prior to that time the helm was neutral and speed 22 knots. The berg was off to starboard to match lookout Fleet's drawing. The simulator was allowed to run for two minutes prior to sounding of a warning bell. This two-minute span was intended to dull the anticipation of the bridge crew. We rang a bell 3 times to simulate the lookouts' first warning.

At the warning, Libby and Patnaud applied about 20 degrees helm (I'll get specifics later). They simultaneously called for reversing the starboard engine, although this had no immediate effect due to the delay time of reversing a steam plant on sea watch.

The effect of the half-over rudder was to maximize its effectiveness. The two students correctly realized that full rudder causes loss of laminar flow which has the consequence of decreasing steering ability. Although it sounds paradoxical, the truth is that too much rudder actually results in less steering.

Once the ship was rotating to port, Libby and Patnaude went to neutral helm. The rotational momentum of the ship continued the left rotation even after the helm was centered. The pair did not attempt to "meet" the rotation to stop it. So, the ship continued to rotate to the left although at a decreasing rate.

As the starboard shaft began losing RPM, they shifted to a starboard helm of approximately the same amount--about 20 degrees--as had been used previously. This rudder combined with the loss of starboard screw thrust was just the right combination to kick the stern to port and clear the berg.

We re-set the computer and did a second run using a 35 second warning bell. Libbey and Patnaude were unable to clear the bow on this run and impact resulted.

Those familiar with the alleged "port around" maneuver will recognize what the two students did to get around the berg. It was nothing more than a successful "port around." However, they did NOT in any way follow the actions claimed as Murdoch's attempt. There are several significant differences:

1. No hard-over rudder command.
2. Reduced RPMs on starboard screw.
3. Shifting helm prior to actual impact.

In the classic "port around" Murdoch used a "hard a-starboard" initial helm command coupled with crashing back of both engines. Our previous runs earlier in the day showed this classic scenario simply did not produce either the actual Titanic accident, or clearing the iceberg.

That's it for today. I'll get serious about the data later. For now I just wanted to give Cody Libby and Matt Patnaude their few minutes of fame for having figured out how Titanic might have successfully dodged the iceberg. Well done!

-- David G. Brown
 
Mar 22, 2003
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Do you at least buy them a couple of beers?
happy.gif
 
Feb 7, 2005
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Fascinating report, Dave. Did Cody and Matt come into the simulator session knowing what they were going to be faced with (i.e., how much prep time did they have before being presented with the Titanic scenario)? When you programmed the iceberg characteristics into the simulator, did you try creating an underwater ice shelf for a grounding scenario?

I'm still having problems with my emails to you, so I'll definitely check here often for the latest information on your excursion to Maine!

Denise
 
Jul 9, 2000
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>>the truth is that too much rudder actually results in less steering.<<

Curiously enough, it would make perfect sense to anyone with a background in aviation. Putting the rudder hard over changes the angle of attack in the fluid medium so that what you have is broken and distorted flow on one side. It's the same thing you see happening in what airmen refer to as a "stall."

From your description of what Cody Libby and Matt Patnaude pulled off (I'd love to see the charts showing how they did it and what happened) they'll make a pair of fine deck officers.
 
Oct 28, 2000
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Answers:

1. No beers.

2. Yes, Cody and Matt were aware of what we planned to do, so they had time to think about the correct responses.

3. Time interval -- I'm not yet ready to say whether the interval was right or wrong. Must look at some of the other runs more closely. However, time does appear to be a factor with Cody and Matt because reducing the warning to 35 seconds caused their solution to fail.

-- David G. Brown
 
Feb 13, 2003
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quote:

It is impossible to steer around an iceberg using any of the traditional scenarios

Dave,
Steering around any object is a simple maneuver when executed properly, which I would, most certainly, consider a traditional scenario.

quote:

However, they did NOT in any way follow the actions claimed as Murdoch's attempt...In the classic "port around" Murdoch used a "hard a-starboard" initial helm command coupled with crashing back of both engines.

Murdoch did not make any attempt to port around anything. His orders merely negated any intentions he might have had to port around. His maneuver was certainly not a traditional scenario.​
 
Oct 28, 2000
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Duke-- Neither you nor I know what happened that night with any sort of precision. What we have are conflicting eyewitness accounts and hearsay of conversations between dead men.

The simulations were of the traditional scenarios of the accident as promulgated by various historians, documentarians, naval architects, and movie makers. What we discovered is that these traditional views do not seem to produce anything approaching a "real" accident.

We also discovered that...as you suggest...driving around an iceberg is possible given sufficient warning. The students who did it quite nicely with 50 seconds advance warning were unable to accomplish the task with a shorter advance warning. In addition, their methods for accomplishing the task were undoubtedly much closer to what you or any other experienced mariner would have done.

-- David G. Brown
 
Mar 22, 2003
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Hi Dave: Just a couple of stupid questions if I may. What was the turning circle (tactical diameter) of the ship used in the simulation, and how long did it take for its head to bear off 22 degrees from the time the helm order was given? If an order for full astern was given, do you know how long in time it was for the way of the ship to be taken off, and how far it would have travelled?
 
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Matt Pereira

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I was thinking bout the incident from the inquiry i read last night about how the helm was hard-a-port when he got onto the bridge and that i think he said was before the sound of rubbing, Way i was thinking was to figure out the time frame is to figure out how long it would take on avg to go from center rudder to hard over and then after that how long it takes to go from hard over port to hard over starboard then you got a good estimate for time frame on the helm commands and then use that time to estimate the distance the ship would have traveled in that time frame at a given speed that she was traveling i have yet to finish what i started since im stuck on exactly how large in dia the titanics wheel was and how long it would take to spin from center to hard over. Just a thought.
 
Oct 28, 2000
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Sam--I have the data, but haven't looked at anything since I got back. Too much other work to get done. However, my plan is to publish everything. The simulated ship is modern configuration, so undoubtedly has better turning characteristics. This means that we have a built-in error towards successful rounding of an object close aboard as compared to Titanic. With regard to the engines, the model is diesel-electric, so we had to simulate steam response by staging the engine orders. The 'puter took about 40 seconds to go from full ahead to neutral.

Matt-- I believe Olliver's testimony indicates the helm was shifted after first contact. He is rather specific that the order from Murdoch came after the rumbling started.

Everyone-- Nobody has an authentic computer model of Titanic. Therefore, what we are doing is simulating possibilities and not reconstructing the actual event. All rudder-steered ships have similar operating characteristics. Given the roughness of the available data about what did happen, I would say that the model ship we used is probably more accurate with regard to Titanic's maneuvering characteristics than the descriptions of events contained within the testimonies are accurate with regard to the real maneuvers that night.

If anyone is dissatisfied, instead of complaining just send a check in the amount of twenty-five thousand ($25,000) dollars US to Kongsburg to computer render Titanic for the MMA simulator. We'll be glad to run the real thing. In the meantime, the experts who designed the simulator say that the ship we ran is the closest thing in the inventory to Titanic.

Even if Daddy Warbucks did fund a computer model of the ship, we would still be only a bit closer to reality. What we cannot get is unambiguous information about exactly what did happen. So, at best all we can do is learn something about the probabilities of various actions that have been proposed as part of the iceberg avoidance attempt.

For instance, the simulator clearly showed something that any experienced shiphandler instinctively knows--hard rudder slows the rate of turn. Murdoch was demonstrably an excellent shiphandler with as much experience on Olympic class ships as anyone. Given those circumstances, would he have ordered "hard a-starboard" or, in light of his experience would he have given some lesser helm order? Our simulation shows only that the hard-over order was inefficient and not likely to succeed--but the simulation says nothing about what orders Murdoch actually spoke or did not speak.

A promise to everyone-- you will get a full report as quickly as I can amass the data and write it down. Delays are purely the result of my generally ineffectual attempts to earn a living.

-- David G. Brown
 
Feb 13, 2003
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David Brown:

quote:

but their method was in no way the actions that Boxhall and Hichens claimed Murdoch ordered

I should think not. Murdoch's maneuver of "crashing back of both engines" (your wording))as claimed by Boxhall, was analogous to a fireman first turning off the water before directing the hose onto the fire.

quote:

I believe that our simulations have put to rest any thought of a "hard over" ice-avoidance maneuver

That, of course, depends on what kind of ice one is trying to avoid. To avoid or to minimize contact damage should an iceberg, for example, be encountered unexpectedly at close quarters, the rudder must be put hard over away from the iceberg. The engine speed must be increased, if not already at full speed ahead. The instant the bow clears, or hits the iceberg, the rudder must be put hard over the other way and the engine speed maintained. This is vital in preventing the hull abaft the pivot point from striking the iceberg.

quote:

In addition, their methods for accomplishing the task were undoubtedly much closer to what you or any other experienced mariner would have done.

You may think so! By their methods for accomplishing the task which you described, I most certainly do not. Of course, you believe, "Murdoch was demonstrably an excellent shiphandler."

Regards,
Collins​
 
Mar 22, 2003
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"Delays are purely the result of my generally ineffectual attempts to earn a living."

Unfortunately, that appears to be a common problem with many of us these days. Look forward to reading your report when you get the chance to write it up. Take care.
 
Jul 9, 2000
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>>Even if Daddy Warbucks did fund a computer model of the ship, we would still be only a bit closer to reality.<<

And even then, it would never be exactly like Titanic. The only way to accomplish that would be for somebody to build a time machine so we could go back and play with the real thing. Not the Olympic and not the Britannic...(even ships of the same class have little quirks which make each a little different from the other)...but the Titanic herself. You just have to do the best you can with the information that's available.

Just a little aside, does anyone have any accounts as to how Titanic and Olympic differed from each other?

>>A promise to everyone-- you will get a full report as quickly as I can amass the data and write it down.<<

And I'm still looking forward to that. Perhaps you could turn it into an article for ET Research. (I know, I'm probably opening up a bit of a Pandora's Box with that one, but more tech articles would be nice to see!)
 
Mar 22, 2003
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Michael asked: "Just a little aside, does anyone have any accounts as to how Titanic and Olympic differed from each other?"

I assume you mean in regard to their turning characteristics and stopping distances? The best there is regarding the turning characteristics and stopping distances of these two ships comes from Wilding's testimony at the British Inquiry and from his NY Deposition during the limitation of liability hearings. Both ships were practically identical in hull, rudder, power plant, etc. The Olympic was also used as a test bed after the Titanic disaster to get more data on turning characteristics and stopping distance under specific scenarios. There is enough information in all of this that we can create a realistic turning model as a function of time, which includes the effect of increased drag that slows the ship during a turn that Dave talked about in his post above, as well as the advance and increase in drift angle that takes place during the early part of a turn. I plan to present this at the upcoming Toledo event in September.

My questions above were aimed at getting a better understanding of what went into the simulation and how closely it would match what we already have available. It was not meant to be critical. What prompted those questions is the information that Dave did report on which gave people the impression that the Titanic could not have avoided a collision with 50 seconds of warning with a "traditional" turn scenario. I believe the words he used were, "It is impossible to steer around an iceberg using any of the traditional scenarios. This is true whether the berg is on centerline or shifted well to starboard. I believe that our simulations have put to rest any thought of a "hard over" ice-avoidance maneuver." As Capt. Collins pointed out correctly, "Steering around any object is a simple maneuver when executed properly, which I would, most certainly, consider a traditional scenario."

Everything depends on the assumptions that went into the simulation, like advanced warning time and specific ship turning characteristics. Maybe using the turning characteristics of the ship that was programmed into the simulator and a 50 second advance warning time were not sufficient to avoid a collision with a simple "traditional" turn away from the object, but a ship with the turning characteristics of the Olympic/Titanic would most certainly have avoided collision with 50 seconds advanced warning if just a simple hard-astarboard helm order was issued at that time. What I'm saying, and this is a critical statement, is that the simulation only proved that the ship used in the simulation may not have been able to avoid a collision with 50 seconds of warning using just a simple hard-over helm maneuver, but to then apply that observation to conclude that the Titanic also would not have been able to avoid a collision is invalid.
 
Oct 28, 2000
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Sam-- you may or may not be right, but the simulations will never reveal if they are correct or incorrect. What they indicate is the probabilities of success with each type of scenario attempted.

One factor that is always overlooked is human reaction time. This is why we started each run several minutes prior to the warning bell. The delay caused the edge to come off the participants. A 50 second advance warning does not mean that the rudder was hard over at 50 seconds because the "Murdoch" had to respond with an order and the "Hichens" then had to respond at the wheel. The actual reaction times of the real men are, of course, unknowable.

-- David G. Brown
 
Mar 22, 2003
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My point Dave is that you cannot state "It is impossible to steer around an iceberg using any of the traditional scenarios" based on what you described in the simulation. Even allowing several seconds for reaction time, the Titanic still would have cleared an object dead on the centerline with nothing more than a hard over helm order with that much warning based on her turning characteristics. That is why I asked about the turning characteristics of the ship used in the simulation. Your conclusion I'm afraid may be invalid.

As they say, "show me the data."
 
Jun 10, 2004
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Reading through this thread, I have the feeling that much is being hinted at but unsaid amongst long time posters who are wary of trampling sore corns.

There is an implication above that Murdoch would not have ordered a hard-over helm, knowing that this would be less effective than a partial helm. There are two possibilities:

a) he ordered a partial helm, but Boxhall and Hitchens stated otherwise at the enquiries because they feared leaving the impression that "more could have been done"? Maybe they were told to say this by Lord Mersey? who would appreciate that the media would grab anything it could to twist a scandal..

b) he ordered a full helm order, because he panicked. Implication being that disaster might have been avoided (just!) had he ordered a partial helm.

I have not seen this issue debated on Titanica before. All right, we will never know, but what seems most likely to you seasoned campaigners?
 
Oct 28, 2000
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Sam-- perhaps I over-stated the case in saying that it was "impossible." My belief is that simulations based upon less than full information...as in Titanic...can at best be instructive, but not definitive.

That said, I think it is highly instructive that the same simulated ship against the same simulated iceberg with the same real advance warning produced two quite different results with only one variable--amount of helm applied. And, as you have said of airplanes and I know is true of boats, this is perfectly in keeping with the real world.

More when I have time to cull the data.

-- David G. Brown
 
Jul 9, 2000
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>>I assume you mean in regard to their turning characteristics and stopping distances?<<

Not quite. I'm referring to any of the little quirks that will be peculier to a given ship. While ships of the same class have broadly similar characteristics, any number of factors can contribute to this from minor irregularities in the hull form to cranky machinary. That's why you sometimes hear stories of one ship being able to do just about anything short of having your baby for you while another ship of the same design would be hooted at as being about as handy as a drunken pig.

One hears stories like that on the waterfront all the time and occasionally, there's some truth to them.

Any minor quirks the Titanic had as opposed to the Olympic are unlikely to have been that much of a factor in the accident if at all, but I was just curious as to what they were if they were observed.

>>Maybe they were told to say this by Lord Mersey?<<

More likely, any "coaching" would have come from White Star representatives and legal counsel. White star and the Board of Trade may have been in bed with each other, but that doesn't mean they were friends. Just allies protecting common interests, and allies often make for fickle and dangerous pets! (In other words, they can turn on you!) Further, anyone on watch would have known that they could become obvious targets for scapegoating if they weren't very, very very careful about what they said.

With your ability to make a living on the line, that tends to be quite the motivator.
 
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