Olympics's inner skin

[Bruce Beveridge]

Well I guess I'll start a new thread on this Olympic double skin issue because it is necessary to address this thought that it was added first and foremost as a way to compensate for hull deficiencies in way of strength. As Mark had stated in one of his responses over in the other Gigantic thread , the Olympic's inner skin structure was not secured to the floors, and therefore did not become a strength member for the benefit of the box girder. It was merely an inner skin just as H&W said it was. It would provide only marginal extra strength, and certainly nothing to compensate for this supposed design flaw of the Olympic class vessel's weak hull. If it were intended as a strengthening addition, they would not have merely riveted it to the top of the tank top but would have had those extension frame pieces in direct contact and securely riveted to the double bottom floors.


As for this worry of excessive list brought on by the flooding of these inner compartments, let me refresh everyone on how these were built. The (relatively thin when put in context) inner skin plating was attached to the inboard surfaces of the web frames which extended inboard by some three feet or so. The 10" channel web frames were fitted with extension pieces to meet the width of the web frames. The inner skin was attached to these extensions and web frames, and again to the double bottom with angles. These connections were caulked watertight of course. Not only was the area between the skin and the shell bounded by the watertight bulkheads for and aft , but they did away with the lightening holes in the web frames and caulked them watertight. So there was in fact quite a few cell divisions within those skins. These skins were, in general terms, merely riveted over the inboard faces of the web frames that were already in place from the beginning.

When Olympic was converted to oil, they caulked the coal bunkers oil tight to handle the fuel for ship's use. Though my memory is a bit fuzzy on this, I do remember G/A plans showing oil stowed in the inner skin cells, but I believe it was cargo, not ship's use. I may be wrong on that, but it is what I remember

Titanic's ( and all of those great liners) hull was built to handle stresses experiences in her type of service. The good shipyards built hulls to handle stresses brought on by known incidents. This was the product of years of shipbuilding experience. How can one accuse H&W of error because one of their ships happened upon a freak accident one night which eventually caused her aft end to rise out of the water and push her beyond her designed limitations eventually causing her to crack her in half? Ships are not designed to sail around with their sterns in the air, they are designed to float on the full length of their keels.

Sorry for any spelling mistakes - it's late

Bruce Beveridge

 

[David G. Brown]

Bruce-- Thanks for some good information.

When you use the term "floor," I am assuming you mean the transverse frame members. Is that correct?

--David G. Brown

 

[Michael H. Standart]

>>Ships are not designed to sail around with their sterns in the air, they are designed to float on the full length of their keels.<<

That's right, they are, and I think that point is quite often missed in the discussions about the merits of any class. That's not to say that the Olympic class didn't have some sort of structural achilles heel...they may have as a result of the usual tradeoffs that come with any new ship design...but absent running into/over icebergs or parking the bow on a mine, none of those issues would have ever been a concern in regular service.

 

[Bruce Beveridge]

After re-reading my prior post, I'm embarrassed at all of the grammar mistakes. I thought I had fixed the text before posting but it was early in the morning. I guess I was pretty tired - please excuse me again.

David,

yes I mean the transverse floors under the tank top plating which made up the double bottom.

Michael,

You explained it well. I don't have anything to add.


We must keep in mind that Titanic's hull failed under stresses that it was not designed to handle, not because of any failings on H&W's part.


Bruce

 

[David G. Brown]

Bruce-- Thanks for that clarification on the floors. Most people don't know or understand the nautical meaning of the term, so I was surprised (in a good sense) when it seemed you were using the word correctly. Now, if we could just straighten out the use of "ceiling."

Let me say from the outset that I do not believe that Harland & Wolff in any way intended to design or build a ship that was not up to the state of 1912 shipbuilding. But, that was a time when ships were growing and changing at a faster pace than the technologies which supported them. In the 1913 storm on the Great Lakes there were several freighters that fared even worse than Titanic under strains they should have survived. Was it rivets? steel? or architecture? Probably all three combined with poor shiphandling and a big helping of luck--all bad.

-- David G. Brown

 

[Michael H. Standart]

>>Was it rivets? steel? or architecture? Probably all three combined with poor shiphandling and a big helping of luck--all bad.<<

To say nothing of the unknown. Setting out in the teeth of a storm is never one of the swiftest ideas on the planet, but in defence of these people, it looked alright when they got underway. Weather forecasting just wasn't what it is today.

I think what we often fail to understand was the core fact that naval architects are on a learning curve and often a steep one. "They should have seen it coming" doesn't take into account that not all the lessons were learned (They still aren't) and that somebody had to learn them. Often as not, these lessons are learned the hard way simply because you can't learn everything in the testing tank. Further, crunching the numbers does you no good if you don't know what numbers you need to crunch in the first place.

Naval architecture was a science very much in it's infancy as a real science in the sense that we understand it, and it shouldn't come as much of a surprise that they got bit by something new from time to time. When you think about it, it's a wonder it didn't happen more often.

Anybody who wants to sling around charges of incompetence would do well to keep this in mind.

 

[Mark Chirnside]

Goodness, so much text and so little sleep. I’ll try and frame a readable reply. I appreciate the expressions of condolence I have received — thank you.

Sam wrote:

What we are arguing over, if you want to call it that, is the primary purpose of adding that double skin. Publicly it was for increased floatation capacity. Privately, I believe that it was most likely recognized that increased hull strength was needed because of the numerous accounts of the Titanic breaking in two, and that adding a double skin design is the best way to accomplish both objectives.

As I see it, everyone is agreed that the inner skin provided additional watertight subdivision; provided a useful space for future conversion to oil fuel; and added strength to the hull. We just don’t agree on the order of those statements, nor some of the relevant circumstances.

David wrote:

First of all, let me reassure Mark that I am not saying the hull girder of the Olympic Class as designed was "seriously weak." I don't have the credential to make such a statement.

I understood you to say that indicate that was your view. What exactly are you arguing, by way of structural strength?

What I do know is that Titanic's hull did break apart as a result of sinking. From the preponderance of the testimonies, and from certain statements made by Wilding, I have concluded that Harland & Wolff also knew about the breakup, even if official policy was (understandably) to deny it occurred. And, Mark has clued us all regarding the doubler strakes installed on Titanic--a common "fix" for hull problems discovered in service.

You may well be right as to H&W’s views as to the break-up. However, you seem to me to be wrong to link the break-up with the modifications to Titanic. I don’t think there is any suggestion that any contemporary liner would have withstood the forces Titanic’s hull endured during the sinking over a period of two hours and forty minutes. In that respect, although I can see that the break-up may have been concealed (publicly), I don’t quite understand your argument.

Adding a double hull to an existing ship is frightfully expensive. It would only have been done as a response to some overriding issue.

While the expense issue is important, your views as to the overriding issue don’t really seem to me to be supported by the evidence. (You’ve previously used the term ‘knee-jerk reaction.) For instance, what figure do you have for the expenditure? I also think it underestimates the worries as to the Titanic’s impact on passengers’ safety. In 1912, Olympic’s average passenger lists were the lowest of the pre-war period — lower even than all years until 1922, when the immigration restrictions began to bite. The reason for this can be speculated upon, yet Titanic seems a safe bet. Olympic was built to be a money spinner, frankly, and — in 1913 and then 1914 — she demonstrably became more popular. (I have excluded the wartime 1914 figures as they distort comparisons.) She set some first class passenger records, and my impression is that revenues were soaring. You have also mentioned the need for economic viability over the long run, and attracting passengers was the way to do that.

Titanic had received fatal damage from the outset. Even if it had design flaws, the outcome was pretty much assured by the nature of the accident. And, the preponderance of the damage to Titanic would have been unprotected by the double sides installed in Olympic.

I agree that Titanic was fatally damaged. However, in my view to your other comments miss the point: it was flooding in boiler room 6 (or rather the loss of that compartment) that ultimately sealed the ship’s fate. And, as I have recorded, Wilding’s testimony acknowledges that and the potential protection afforded by the double skin. We also need to bear in mind that Olympic was a completed ship and as such any modifications had to be rooted in that reality.

So, the public "eye wash" cover story might have been to protect against a sideswipe accident (which never occurred), but that explanation simply doesn't hold up to scrutiny.

Again — this seems to be at odds with the issue of boiler room 6, and is merely your own opinion.

What does hold up is that double sides would have added enormous longitudinal strength to the hull.

It’s here that we may differ. I think you have yet to demonstrate that they would have added enormous strength. (I have no problem agreeing that the double skin would have increased hull strength to a degree, but instead refer you to Bruce’s comments.)

The height of the bulkheads in the original design was sufficient to protect a ship that was not already fatally damaged.

This would be another aspect where we disagree. It seems false to raise the issue of heightened bulkheads — your views as to the reasoning for the bulkheads being extended seem to be more opinion than demonstrable fact.

The idea that the double sides were installed with an eye toward the conversion to oil seems ex post facto.

My problem earlier was that you said I had assumed that the shipbuilders took into consideration a future conversion to oil. I had not — it was something from period sources, and as such you misrepresented what I had said.

Regarding coal and Laurentic--the story is that the ship was built to a price. And, that's probably true. But, a really parsimonious ship owner would have gladly paid extra for an oil ship in 1927 simply to save money over the long term.

I’m sure it is true that Laurentic was built to a price. The problem with your argument is that it is a fallacy: you’ve assumed that ‘a really parsimonious ship owner’ was involved in that decision. There are many examples of bad financial decisions from this period. In any event, Laurentic was a distraction from the real debate — as I said earlier.
Michael wrote:

On the matter of double skins, I can see where David is coming from. They have virtues in terms of some extra protection, but it comes at a price.

I’m not disputing that. Presumably that’s why Wilding thought it was a matter of careful consideration as to the merits and pitfalls.

While they may prevent a penetration of the inner hull, having a section open to the sea also opens the door to problems with assymetric flooding. If you have enough stability and reserve boyancy to avoid sinking, this isn't that big a deal. If you don't, then getting the lifeboats away becomes an issue. Especially if the list is severe enough to make launching half of them impossible.

Agreed — yet I think Sam’s comments are relevant. There’s a clear distinction between the double skin and longitudinal compartments as in the Cunarders, especially in terms of their influence on the ship’s list. Similarly, listing is an all too real problem and even a vessel free of any double skin or longitudinal bulkheads can succumb as it loses buoyancy during the sinking process.

BTW, Mark, when you have the time, I'd be interested in hearing about the whacky propulsion schemes you've alluded to.

According to my pension provider, my projected retirement date would conservatively be projected at February 2060 when I reach the age of seventy-five.

Bruce wrote:

As Mark had stated in one of his responses over in the other Gigantic thread , the Olympic's inner skin structure was not secured to the floors, and therefore did not become a strength member for the benefit of the box girder. It was merely an inner skin just as H&W said it was. It would provide only marginal extra strength, and certainly nothing to compensate for this supposed design flaw of the Olympic class vessel's weak hull. If it were intended as a strengthening addition, they would not have merely riveted it to the top of the tank top but would have had those extension frame pieces in direct contact and securely riveted to the double bottom floors.

I agree, and I think that is the one of the really key arguments in this whole debate. I don’t think sufficient evidence that the double skin’s primary purpose was to provide strength has been forthcoming.

Though my memory is a bit fuzzy on this, I do remember G/A plans showing oil stowed in the inner skin cells, but I believe it was cargo, not ship's use. I may be wrong on that, but it is what I remember

The oil in the inner skin was almost 1,700 tons out of a total capacity of 5,200 tons — roughly — so you’d have 3,500 tons of oil left, which is only just enough for a round trip at 21-22 knots according to the 1934-35 oil consumption figures. It does not seem to me that there would have been a sufficient reserve unless the double skin’s oil was also used for the boilers, especially in light of Olympic’s reported increased range after the conversion in 1920.

How can one accuse H&W of error because one of their ships happened upon a freak accident one night which eventually caused her aft end to rise out of the water and push her beyond her designed limitations eventually causing her to crack her in half? Ships are not designed to sail around with their sterns in the air, they are designed to float on the full length of their keels.

Agreed.

Best wishes,

Mark.

 

[Michael H. Standart]

>>You may well be right as to H&W’s views as to the break-up.<

I'd be amazed if Harland and Wolff didn't know about it and even more amazed if Edward Wilding himself didn't do the relevant number crunching then quietly pass it on to Lord Mersey. There were too many witness statements to the effect coming out publicly in the U.S. and Mersey's people were well aware of it. Bill Wormstedt in my opinion, did a wonderful job of showing that Mersey's court tried a little too hard to make sure it was never mentioned in sworn testimony.

Unknowns aside, these people were note dopes and once it was known there was something to look for, out came the slide rules followed by that cold sinking feeling once it was realized what it meant. My own bet was that the real figures were mulled over in the smoke filled backrooms and away from the eyes of lawyers who could make something of it in the liability suits they knew were coming.

Did they over-react?

Maybe.

It's not really all that unusual for a ship to come unglued in the sinking process for one reason or another. Depending on the nature of the damage, the seastate and what have you, you can have anything happen from nothing at all...beyond the foundering...to the entire hull girder disintigrating the way the Derbyshire did.

However, when you have a potentially hostile power looking on from just across the channel, the fact of ships built of your best battleship steel breaking up just isn't one of those things you want to admit to in public.

 

[Samuel Halpern]

Well I guess my speculative reasoning about the primary reason for adding the double skin was wrong. Thanks Bruce for the detailed information. I assume the double skin design for Britannic was similar?

 

[Bruce Beveridge]

Sam,

Yes Britannic's was the same for the most part. Take a look at the one image of the Britannic's internals of the inner skin photo in one of those McClusky books. I also have the Olympic's midship cross section from the 1912-13 refit which indicates the scantlings of the inner skin.

 

[David G. Brown]

Bruce-- Since the inner sides installed within Olympic were reputed to be watertight, how were they secured at the tank top level? Certainly, that joint could not have been left open or there would have been direct flow of water between the newly-created side tanks and the interior of the vessel.

--David G. Brown

 

[Bruce Beveridge]

David,

They ran a 4" x 4" x .60 angle longitudinally to secure the bottom of the plating to the tank top.

Bruce

 

[David G. Brown]

Bruce-- Thanks for the details. This is exactly as I thought because it was the only option to them.

--David G. Brown

 

[Bruce Beveridge]

I wanted to make a comment on the oil used inside of Olympic's inner skin. Please allow me to ramble a bit. In most of these points I will state below, I am preaching to the choir.

I had thought that the oil carried within the inner skin of Olympic was merely cargo. However, I was wrong, and Mark was able to provide the period information that stated that the oil in the inner skin tanks was in fact for the ship's use.

In regards to whether H&W anticipated the inner skin space to be used as oil tanks, there was some debate over whether or not this was a possibility in 1912-13. I stayed back from comment on this because I didn't have the reference where I thought I had read a mention of oil usage in. I still can't find the article, but it was in a late 1912 or 13 edition of "Engineering" or "The Engineer". And in that, I still couldn't remember what the reference to oil was specifically. This article also mentions the combining of soil pipes, and raising of the bulkheads in the refit of Olympic etc.

When I read the exchanges about the oil use anticipation on Olympic in 1913, and specifically the opinions against it, I knew that in fact shipbuilders of this time were well aware of the benefits of oil fired furnaces, and did in fact anticipate the use of them. They would be stupid not to.

Yes - the Admiralty was using the oil for firing boilers first, as the Admiralty was the sounding board for much of the shipboard innovations. For instance, if an inventor had a new anchor design he wished to produce and make money off of, he pitched it to the Admiralty first, not the Merchant Marine. If the Admiralty placed an order, then the inventor was successful. This scenario is true for the Hall's patent anchor and even Trotman's anchors - and of course Parsons to name only a few examples.

The shipping industry in Britain in this era did not operate in a vacuum. The big wigs of these builders sat on some of the same government boards and they certainly knew what each other was doing. As much as they competed with each other, they also shared information on a gentlemanly level. With this, you can guarantee that if the Admiralty was successful with oil fired boilers since 1906, that the ship owners were keeping an eye on the technology. Also, I would agree that the problem with oil fired boilers in 1912-13 probably had more to do with availability of product then the ability to make the coal to oil conversions. There was also a lot of old timers who didn't like how dangerous this new technology was.

I am very surprised that a ship was not built by H&W in 1912 or 13 already fitted with oil burners. Especially with the oil supplies readily available in the US. Europe and the Continent was another story of course. Why H&W built a coal firing ship after W.W.I is open to debate, but it has no bearing on this anymore. I was told by a historian that he believed H&W had an oil fired cargo carrier already running in 1913, but that reference could not be found. It was off the top of this gentleman's head from his past readings.

As for Olympic, Mark Chirnside found a few references, and I bet could get more. He has O.K.'d me to post these below.

Here are a few:


It was written in 'Railway and Travel Monthly' that "During the [1912-13] refit she was fitted with two oil fired boilers as an experiment." We will be locating the issue and date of this reference.


Also in the New York Times from December 10th 1912:

"OIL FUEL FOR OLYMPIC" Liner Will Carry Supply Between Inner and Outer Hull as Experiment.

Belfast, Dec. 9 - The White Star Line has taken an important step in connection with the alterations to the Olympic, now being carried out by Harland & Wolff. The alterations include the construction of what is practically an inner or second shell, divided from the outer shell by a three-foot space. The owners were greatly exercised as to how the space between the shells could be utilized. It has now been decided to use the space in the forward and after bunkers for carrying oil, which will be used as fuel for one of the boilers.

The owners are hopeful that the trial, which will begin immediately after the Olympic resumes her sailings next spring, will be entirely successful. In that event provision will be made on the new White Star liner Britannic, now in course of construction at Belfast, for the utilization of oil as fuel, the whole of the space between the two hulls of that vessel being used for storage purposes.


I think these references about seal up this issues about H&W anticipating oil fuel for the Olympic class liners.


Regards,

Bruce Beveridge

 

[Michael H. Standart]

>>When I read the exchanges about the oil use anticipation on Olympic in 1913, and specifically the opinions against it, I knew that in fact shipbuilders of this time were well aware of the benefits of oil fired furnaces, and did in fact anticipate the use of them. <<

If I recall correctly, they knew of the potential benefits for at least half a century. Bill Garzke has a discussion of that in his book "Titanic Ships, Titanic Disasters." and mentions one period vessel where something was tried. (I'll have to dig around for the reference.)

The problem as you mentioned was supply. Oil was the coming thing but not well established, whereas coal was available just about everywhere so it would make sense to continue building coal fired vessels until a reliable supply infrastructure was established.