Could Titanic have survived a head-on impact?

[Bob Read]

Why game out a scenario that never occurred? If there was something that they might have wanted to defend against is that the ship broke in half. I can’t recall any other questions about a head on collision but for some reason there were more questions about a break-up. Personally I don’t see why there would be much interest in doing calculations for a head-on collision unless they wanted to change the procedures for collision avoidance. One would think they would put more research into strengthening the lateral aspects of the bow.

 

[Richard C Elliott]

Why game out a scenario that never occurred?

Good question, so why did Wilding introduce the idea, completely unasked for, at the inquiry and why did he appear to have the rough figures already to hand.

Personally I don’t see why there would be much interest in doing calculations for a head-on collision unless they wanted to change the procedures for collision avoidance.

I suspect they originally did them to calculate the conditions under which the collision bulkhead would be fully protective in a head-on collision. There were no legal requirements to do that but Harland & Wolff may have been a bit ahead of the game in that respect. Edward Harland was a major figure on the 1891 Board of Trade committee that drew up the compartmentalisation regulations and first introduced the term 'collision bulkhead'. He was also a Member of Parliament and participated in various debates about whether the bulkhead regulations should be enforced by statute. It is not unreasonable to think that he may also have instilled something of a 'compartmentalisation culture' in his subordinates and successors at the yard, so they may well have gamed out various collision scenarios.

 

[marina_irc]

I agree that it is possible Wilding did that. In fact if he had been an engineer with no specific knowledge of the Titanic's structural details that is probably what he would have done. In reality he was a naval architect from the design team with 'insider' access to detailed structural information, which is why I think it is more likely that he started from a strength calculation for Titanic.

Well, he needed to start with "Arizona" no matter what because the mechanical properties of sea ice were not understood well enough to do otherwise at the time. Your article makes a significant assumption in how the impact is modeled.

 

[Arun Vajpey]

Why game out a scenario that never occurred? If there was something that they might have wanted to defend against is that the ship broke in half. I can’t recall any other questions about a head on collision but for some reason there were more questions about a break-up. Personally I don’t see why there would be much interest in doing calculations for a head-on collision unless they wanted to change the procedures for collision avoidance. One would think they would put more research into strengthening the lateral aspects of the bow.

Bob has a point there. While I agree that Wilding and others must have previosuly calculated the effects of a head-on impact with an iceberg with the Olympic class liners, his testimony did come across as rather bit of gun-jumping. It might have been true, but there is something unusual and even unempathic in the way in which that truth was delivered.

Wiliding also testified that all the off-duty firemen berthed in the forepart of the bow would have been killed in that hypothetical head-on impact, also completely true. But let us transport that scenario to the bridge and Murdoch's position; no matter how highly trained the man was, he simply did not have the time to consider the logistics of a head-on collision and compare it with trying to swerve away. It is instinctive human nature to try to avoid a blow; if someone throws a punch unexpectedly at your head, you instinctively try to sway out of the way even if that someone was a 8 year old child and you were a heavyweight boxer - because your brain would not have had the time to calculate that the child was more likely to hurt his/her fist than your jaw.

It was likewise with Murdoch. The first reaction after he realized what was happeneing would have been to try and avoid impact and when he realized some seconds later that it was not possible, try to mitigate damage. But also consider the alternate scenario: IF he had decided not to turn the ship at all but try to slow it down by stopping or even reversing the engines (which would have had little effect at that speed and distance left), we can only imagine how people like us would condemn the man for the rest of his miserable life by accusig him of needless manslaughter of all those firemen when he could "easily" have swayed out of the way or even settled for a relatively "harmless" glancing blow.

If the Titanic had struck head-on and not sunk just like Edward Wilding calculated, none of us would have known about the other scenario that lasted 2 hours and 40 minutes.

 

[marina_irc]

A. Assur and W. Weeks' The Mechanical Properties of Sea Ice is a good introduction, @Richard C Elliott Not focused on bergs but the fundamental mechanics of materials will hold up; I worked at CRREL for most of my professional career to date and can speak to the body of knowledge fairly well.

Basically, the ice berg will displace and will suffer damage. You must account for this, and because of the uncertainty in the size of the berg and the fact this science wasn't done in 1912, the best way to do so is by scaling and deducing informatikn from the known facts of Arizona's damage.

 

[marina_irc]

More generally: The Mechanical Properties of Ice, by John W. Glen.

 

[Richard C Elliott]

@marina_irc thank you for those links. I will read them with great interest!

You are right, of course, that I have made an assumption but I don't think it significantly affects the conclusions. Both Sam Halpern and myself were initially only examining the plausibility of Wilding's suggestions and for that purpose we don't need great accuracy. If we took into account deformation and movement of the berg then the damage distances and forces involved would be less, but probably in the same ball-park and subject to similar limitations at the extremes of the range.

If, as I speculate, H&W had previously carried out such calculations with respect to the effectiveness of the collision bulkhead they definitely would not have incorporated data on the properties of ice. They would not have been thinking specifically of an iceberg impact but more generally of a headlong collision with any solid structure (like a harbour wall) and would simply have considered it immovable for the purpose of the calculations.

 

[Samuel Halpern]

Personally I don’t see why there would be much interest in doing calculations for a head-on collision unless they wanted to change the procedures for collision avoidance.

Not necessarily. As stated in the main reference I used to derive my results:
"Collision and grounding events contribute significantly to ship structural damage and ship losses. According to statistical analysis, Hu (1998), ship collisions and groundings are responsible for about half of all ship losses and are responsible for about 70% of all polluting events caused by shuttle tankers. It can be concluded that collisions and groundings are one of major risks to the safety of ships. To reduce the risks to ships and the environment, it is important to minimise the probability of occurrence of collision and grounding incidents and also to reduce the consequences following such incidents."

The question of what would have happened if Titanic struck the berg head on has been asked over, and over again, with some people making all sorts of claims based on their gut feel. The question for me was not should Murdoch have acted differently. The question for me what to try and quantify a what if scenario. That is also why in my paper I imagined a scenario where the ship ran into a fog bank unexpectedly, and there was simple no time to react when a wall of white loom in front of it.

By the way, the recommended procedure today when the OOW is faced with collision event where avoiding contact is not an option is quite clear and maybe somewhat surprising. From 'A Guide to Collision Avoidance Rules:"

“The engines should be stopped, and the helm should be used so as to achieve a glancing blow rather than a direct impact. The damage would probably be the least serious if the impact is taken forward of the collision bulkhead.”

 

[marina_irc]

@marina_irc thank you for those links. I will read them with great interest!

You are right, of course, that I have made an assumption but I don't think it significantly affects the conclusions. Both Sam Halpern and myself were initially only examining the plausibility of Wilding's suggestions and for that purpose we don't need great accuracy. If we took into account deformation and movement of the berg then the damage distances and forces involved would be less, but probably in the same ball-park and subject to similar limitations at the extremes of the range.

If, as I speculate, H&W had previously carried out such calculations with respect to the effectiveness of the collision bulkhead they definitely would not have incorporated data on the properties of ice. They would not have been thinking specifically of an iceberg impact but more generally of a headlong collision with any solid structure (like a harbour wall) and would simply have considered it immovable for the purpose of the calculations.

The reason I am suggesting you consider a derivation from Arizona is that we know Wilding was thinking a lot about her and your own calculations suggest that for the baseline estimates of Titanic's strength that Wilding was optimistic about the damage estimate; he didn't think third class passengers would be killed. So my supposition is that extrapolation from Arizona will take into account based on empirical data in the historical record the reduction in damage reflected by the iceberg itself both sustaining damage and being displaced in the collision and therefore may actually yield a more reliable result.

 

[Richard C Elliott]

... extrapolation from Arizona ... ... may actually yield a more reliable result.

It might possibly yield a more precise result of the damage length in the 'Wilding' scenario of a full speed collision, but is anybody really interested? We are discussing a hypothetical, 'what if', scenario. All we are asking is whether his predictions are plausible. An approximate answer will suffice.

A derivation from the Arizona data would not help if we then take the next step of considering how the estimate changes with variation of the input assumptions. We would still need a rough mathematical model of the relationship between crushing strength, damage length, mass and velocity for the Titanic.

 

[Bob Read]

Based on the speculation that Wilding did run calculations for a head-on collision, is there anyone who believes Murdoch was mistaken in taking evasive maneuvers? Is there room for one more villain?

 

[Richard C Elliott]

Based on the speculation that Wilding did run calculations for a head-on collision, is there anyone who believes Murdoch was mistaken in taking evasive maneuvers? Is there room for one more villain?

Certainly not me Bob. It would have been considered sheer lunacy!

If they had been running at half speed the case for a head-on collision would have been better but even then I think he would have opted for an evasive manoeuvre. As Sam pointed out above, aiming for a glancing blow on the bow is still a recommended practice.

 

[marina_irc]

Based on the speculation that Wilding did run calculations for a head-on collision, is there anyone who believes Murdoch was mistaken in taking evasive maneuvers? Is there room for one more villain?

Murdoch took the correct action.

That last sentence is quite unbecoming.

 

[Bob Read]

That last sentence is quite unbecoming.

“The part that stings in any rebuke is the truth”.

 

[Samuel Halpern]

is there anyone who believes Murdoch was mistaken in taking evasive maneuvers?

Not any of those who are actively participating in this discussion.