Modern Cargo & Passenger Vessel Safety


Jan 5, 2001
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That discussion got me thinking about modern requirements for sub-division on passenger vessels, etcetera. I’d like to make clear that I am only stating my opinions here from what I’ve heard over the years; I don’t mean to criticize any opinions offered in the past.

I was reading an article on the subject a while ago and there was some mention that modern vessels are usually just built to satisfy the 'minimum requirements' -- such as two watertight compartments flooded. I know of one large passenger vessel (mentioning no names) that is roughly 850 feet long, with eighteen main watertight compartments within the hull (not including double bottom, etc.) and it can only float with a maximum of *two* flooded. Not float in safety with two flooded, but *will only float with no more than two flooded.* I guess to make ship owners comply you have to raise the standard of the regulations. It annoys me when people criticize Titanic as one modern paper stated that her sub-division was meeting modern standards in all ways except some minor stability tests. The usual whine is ‘the watertight bulkheads only went up to E-deck.’ Well, pardon me, but wasn’t that twice as much as the minimum margin recommended by Edward Harland’s committee in 1891? (From memory there.) I seem to recall bulkhead plating twenty percent in excess of requirements. Floating with any two compartments flooded in safety, possibly with all four forward compartments flooded in good conditions; that seems safe to me. Yes, she could have been safer with hindsight; but at the time surely there were no complaints?

On a slightly different issue, over the years there have been theories that the ship’s construction was flawed — deliberately or not. Well, isn’t this disproved by the sister Olympic floating safely for 25 years? She lasted a long time in service before economic considerations including surplus tonnage forced her withdrawal.

Compared to modern vessels — of many types — I consider Titanic’s construction to have been fine. Yes, Lusitania’s subdivision could be argued better, but that was to Admiralty requirements and when it mattered she went down like a brick.

Some modern examples worry me — all this building to minimum requirements, for a start. Bulk carriers are inherently unseaworthy by some accounts, one maritime expert considering that any bulk carrier over fifteen years old is considerably at risk of structural failure. The Derbyshire was four years old when she foundered in 1980, apparently the result of inadequate hatch covers buckling under pressure of waves; one buckled, her bow settled; then another broke, flooding a second compartment, her bow settled; then it went faster and faster. Yet a sister of hers (the Kowloon Bridge) cracked her hull up and foundered in 1986, slipping off some rocks — where she had run aground after being abandoned as she was cracking-up quickly — and sinking in deep water, after barely a decade of surface. Other bulk carriers have experienced alarming structural failures. I just wish standards could be improved further. Sailors are dying because of safety margins that could be improved — hatch covers for example are surely simple to strengthen?

I have researched into previous liners (o.k. not cargo vessels!) — Olympic for example didn’t experience any sort of hull plate cracking until she was sixteen, after hard service, and this wasn’t bad compared to other vessels. Berengaria was the same, although she needed new plating in the 1930s because her bigger cracks could not be welded (apparently) whereas Olympic was adequately repaired with much welding and a little doubling. Aquitania was suffering fatigue and troublesome expansion joints by 1930/1, yet she served until 1950; I don’t have much on her. Homeric’s stern shell plating was cracking up from 1925 onward. Some even fell off the ship at one point! Mostly this was near her propellers. Mauretania apparently had fatigued plating near her propellers and some small bit of her bossing fell off. Majestic cracked badly after two years in service; Leviathan after fifteen in a storm; both vessels had ‘severe extensive structural breakdown’ and from what I can gather experienced extensive cracking.

These older vessels in some cases had notable problems, but mostly after many years of service. Only in a few cases did they have trouble after a few years. There must be some construction improvements that can be made on bulk carriers and cargo vessels? Perhaps framed at shorter intervals, thicker hull plating especially in places of increased stress. Yes, it would entail somewhat more expense, but isn’t it better to build one tanker that will last twenty-five or thirty years rather than one that will be worn out after fifteen or twenty? The extra lifetime will probably compensate for more expensive construction. Surely even better surveying — or more regular surveys?

Any insights would be appreciated, or am I rambling?…

(I haven't researched this really -- just a jumble of thoughts, ill-informed or not.)
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Best regards,

Mark.
 

Paul Rogers

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Hi Mark.

You said: "On a slightly different issue, over the years there have been theories that the ship’s construction was flawed — deliberately or not. Well, isn’t this disproved by the sister Olympic floating safely for 25 years?"

I don't think you can base your above opinion solely on Olympic's survival. From memory here, Capt. David Brown implied that an element of flawed construction could be the fireman's tunnel / staircase / vestibule area. If this area alone were damaged, it would be possible still for the ship to flood in a number of compartments because of the design. (David: I hope I'm paraphrasing you reasonably well. If not, please correct me.)

Olympic never suffered damage to this area, so this "design flaw" was irrelevant to her. Bearing in mind that Titanic and Britannic both suffered bow damage in this area, a record of "Three built, two sank" isn't too impressive!

However, as a landlubber, I'm hardly qualified to comment!
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Regards,
Paul.
 
Jan 5, 2001
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Hi Paul!

Sorry for the poor wording
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-- I was referring to the *'flawed construction'* as the discredited brittle steel theory, for example. Or just generally using inferior materials in the vessel's construction. There are of course others that have since been disproven.

Whether the *design* of the firemen's tunnel was flawed, I haven't really an opinion at present.

Best regards,

Mark.
 
Dec 4, 2000
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My opinion is that the firemen's tunnel in combination with the circular staircases represented a serious breach in the subdivision of the Olympic class ships. Damage to the vestibule at bulkhead D could cause up to four watertight doors (2 automatic and 2 manual) to fail to close. In that case, All three holds and boiler room #6 become interconnected in terms of flooding. Bulkheads "B," "C," and "D" are rendered meaningless. A single rather minor injury could cause the loss of the ship. I do not believe this design would pass safety inspections today.

As far as the steel goes, Titanic's was as good as British mills could produce. Someone with a passion for history might want to explore the implications of Titanic's steel with regard to the two World Wars with Germany. After all, the steel in Titanic was "battleship steel."

--David G. Brown
 
Dec 2, 2000
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I never really gave the Fireman's tunnel much thought, until...much to my surprise...I found out that there was no way to make the stairtower penetration through Bulkhead "B" watertight. Quite a gaff there, and it was never really corrected to my knowladge.

Mark, IMO, made some good points about comparing the margin of safety in the Olympics to be better then what exists today. How many cruise ships/liners can remain afloat with up to four compartments flooded? My bet is that the list is a short one!

Regarding three up and two sunk, befor we get too caught up in that, we may do well to consider the circumstances. Titanic was killed by bad navigation which caused six watertight sections to be opened to the sea. All things considered, it's a wonder she remained afloat as long as she did. As to the Britannic, it helps to remember that parking on a mine is notoriously unhealthy for any ship.{The battleship HMS Audacious was sunk by one.) She wasn't badly handled up to that point, just damned unlucky.

In retrospect, it was clearly unwise to try and beach the ship, and having those portlights on E deck open when they should have been closed was quite a blunder, as was having watetight doors open to facilitate shift change in the mainspaces. Still, were it not for that mine, there would have been no problem in the first place.

Mark, regarding the Derbyshire, I seem to recall that there was a problem with they way the ships were put together as well. Something about beams being welded a fraction of an inch out of line...

Cordially,
Michael H. Standart
 
Jan 5, 2001
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Hi Paul, Dave, Mike!

Good points on all sides, thanks. For Britannic, I am afraid that I still regard the portholes as being a factor of the greatest importance.

<FONT COLOR="ff0000">regarding the Derbyshire, I seem to recall that there was a problem with they way the ships were put together as well. Something about beams being welded a fraction of an inch out of line...

I've never heard of this! Sounds interesting though. Talking about thickness of steel, etc., are any investigations going on at present to improve the structural integrity of bulk carriers?

Another thing is the single propeller which if I'm not mistaken usually drives a bulk carrier -- twin propellers would provide a better safety margin, allowing more margin for the steering gear in case of failure or one engine failure.

Best,

Mark.
 
Dec 4, 2000
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The loss of 2/3 of a vessel class to very similar damage cannot be overlooked. The Olympic class of ships had a "glass nose" and the only thing that made them different was the firemen's tunnel and stairtower arrangement. That Olympic herself never suffered bow damage that brought this flaw into play is pure serendipity. Of course, on the opposite side of the coin, name two other ocean liners that suffered similar damage to their bows...hmmm. Fate does twist in a most curious manner.

Mark's comments about the portholes brings up a problem with passenger ships--by nature they are full of holes called "portholes" and "doors." These do not pose a threat under normal circumstances and cannot be considered as the primary cause of flooding in Titanic's case.

However, secondary flooding (the technical name for water through these openings) is often the source of the fatal flooding. A World War II book called "How To Abandon Ship" by Phil Richards and John J. Bannigan addresses this problem. They say that when a damaged ship floats for a long time and then sinks, secondary flooding is the usual cause. Titanic seems to follow this pattern in that it floated with only a bow-down attitude and then the sinking gained momentum.

Many authors have pointed out the lack of a "bulkhead deck" in the Olympics as a flaw. A "bulkhead deck" is a watertight deck over the tops of the bulkheads to prevent water from spilling compartment to compartment as it did in Titanic. Such a deck would seem to have prevented the tragedy. However, if secondary flooding put water on top of that deck..and the spaces below remained dry..then the balance of the ship would have been upset. It would have listed and probably rolled on its side. That would have prevented the launching of lifeboats and thereby raised the death toll.

--David G. Brown
 
Dec 2, 2000
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Mark, I'm sure naval engineers look into this sort of thing all the time. The question is how much can you afford? Cargo vessels don't do a lot of frequent manuevering, rarely go into combat, and operate with very small crews. Adding an extra screw would increase the margin of safety, but there would be just that much more in the way of fittings and equipment that would need attention.

Regarding the Derbyshire and her sisters, I seem to recall that they were assembled by way of modular techniques, and the fatal misalignment in the horizontal beams was at the aft bulkhead seperating the engine room from the cargo spaces. I'll have to run that tape I made of the DISASTER series which mentioned this. (I may have the details mixed up.) The consequences of this misalignment was that there was a fatal weakness at the point where these beams would have met otherwise.

Cordially,
Michael H. Standart
 
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Mark -- There are strong arguments for single screw. For one, a single installation provides more power than twins of the same nominal horsepower. Thus, twins have to be bigger, heavier, and (consequently) hungrier in terms of fuel. Also, it costs twice as much to maintain twin plants as a single. And, your manning requirements are higher.

Safety improvements of twins can be marginal. In the U.S., insurance companies have required towboats be twin screw because of a theoretical safety improvement. The theory is that the towboat will still have power to maneuver if one plant quits. But, experience has shown that during an engine failure these twin screw towboats are usually unable to maintain safe steerageway. So, many of them are no safer in an engine failure than a single.

Maneuvering with twins is easier, but I've seen some ol' timers "walk" single screw tugs sideways against the wind.

--David G. Brown
 
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Hi Mike, Hi Dave!

Thanks for your comments. I think after those facts you have pointed-out that a twin screw would be little better at best, if at all better considering the additional manning and technical requirements that have been pointed out. I hadn’t thought of the increase in fuel consumption at all, neither the additional manning required.

I like to note these specific points:

<FONT COLOR="119911">…a single installation provides more power than twins of the same nominal horsepower. Thus, twins have to be bigger, heavier, and (consequently) hungrier in terms of fuel…it costs twice as much to maintain twin plants as a single. And, your manning requirements are higher.

<FONT COLOR="ff0000">…I seem to recall that they were assembled by way of modular techniques, and the fatal misalignment in the horizontal beams was at the aft bulkhead separating the engine room from the cargo spaces…The consequences of this misalignment was that there was a fatal weakness at the point where these beams would have met otherwise.

It’s an interesting theory, wasn’t this area ‘frame 65’? I seem to recall that notorious figure. The Derbyshire I find particularly interesting because of her sudden foundering --- something like three minutes --- and she disintegrated so rapidly and catastrophically.

There was a good quote, I forget who said it, but it was something along the lines of a ship needing to be ‘a watertight ship, a seaworthy ship and a strong ship; if that’s the case, there’s no reason why it (the ship) should sink.’ I suspect such a design flaw would come under the latter.

Naval engineers are probably looking into this in detail, but I still find it so interesting that the safety record for bulk carriers in particular seems so poor. Is there any reason generally why such a form of ship would be weaker? Or is it something all bulk carriers have as a general design flaw? I know that the weaker hatch covers (thirty percent of the deck area, having only one-tenth of decking strength) have been identified and recommendations are presumably being implemented to rectify this, double hulls also being a relatively recent improvement to some bulk carriers, yet I still wonder whether these will improve the safety record significantly in the long term. (Sorry, all these illogical, inflowing questions!) This is an interesting discussion indeed and I would like to say thanks especially for your expert insights.

Best regards,

Mark.
 
Dec 4, 2000
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Mark -- You will have to check out my next book, "White Hurricane." I devote considerable effort to finding the flaws in the bulk freighters on the Great Lakes during 1913. Curiously, rivet failure and cracked steel plays a part. Sound familiar? The real problem on the lakes, however was the length to depth ration which was too shallow because of the shoal waters the vessels navigated. (End of crass commercial plug!)

-- David G. Brown
 

Erik Wood

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Apr 10, 2001
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You would be very surprised at just how little certain flags require for there ships. Compartmentation is a fairly tricky part of ship building as well as damage control.

Modern Cruise ships have (for the most part) the three compartment limit. Meaning that loss of the a fourth compartment to water would mean the end of ship. Don't read to much into this. This a very basic thought process which is so far from the truth that it isn't even remotely funny.

Cargo ships such as those on the great lakes really don't have any water tight compartments at all. Ships like the Matsonia a ship run by Matson Line has several basic ones. The engine room, shaft alley, and one extra machineary space. The rest is pretty much open. Cargo holds where never designed to be water tight. On Great Lakes frieghters there is just no way to make the 4 + cargo holds watertight. They are divided for the most part into four sections by a section of steel plating about a quarter of an inch think. The plate stops about 5 feet short of the top of the hold and very often there is some sort of "screen" there. On the Great Lakes the ships are self unloaders meaning there is a conveyer belt that runs through the bottom of the ship that takes out the cargo.

Every flag has different standards. Liberia and other mid east flags hardly require anything. Most modern cruise ships are divided into about 11 seperate compartments. Most of which are engine spaces, but they also include the main galley, bow thruster rooms both forward and aft and various other compartments. As mentioned earlier in this post most of the cruise ships use the 3 space rule. Meaning that if you loose three if you begin to loose four the ship goes down. This isn't true. If you loose to forward compartments and one in the middle then two smaller compartments aft you will probably stay afloat.

The pain is that a relief Captain is expected to know all about all two or three classes of ships that he or she may in counter.

ERik
 
Dec 2, 2000
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Mark, was it frame 65 or 95? Both numbers seem to be sticking. I guess I'll have to dredge up that tape to double check or do a websearch.

One thing that stands out about bulk carriers is a lot of open space in the cargo area. nesseccery as the idea is to maximize the ship's cargo carrying capacity...but (You knew this was coming)...there are inhearent weaknesses which just dont go away. With such large and cavernous holds and no decks all the way down, structural strength is going to suffer. If you couple that with any flaws that creep in during construction and add in a nasty storm with sprung hatch covers, you're going to be in heap big trouble!

Cordially,
Michael H. Standart
 
Jan 5, 2001
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Thanks all for your interesting responses. Sorry for this slightly late reply.

Hi Dave!

<FONT COLOR="ff0000">Curiously, rivet failure and cracked steel plays a part. Sound familiar? The real problem on the lakes, however was the length to depth ration which was too shallow because of the shoal waters the vessels navigated. (End of crass commercial plug!)

*Very* familiar! I'll look forward to your book -- isn't it due out around April or May? Is it the same kind of format as 'Last Log'?

Hi Erik!

<FONT COLOR="119911">Ships like the Matsonia, a ship run by Matson Line has several basic ones. The engine room, shaft alley, and one extra machineary space. The rest is pretty much open. Cargo holds where never designed to be water tight. On Great Lakes frieghters there is just no way to make the 4 + cargo holds watertight. They are divided for the most part into four sections by a section of steel plating about a quarter of an inch think. The plate stops about 5 feet short of the top of the hold and very often there is some sort of "screen" there..

That's interesting -- a while ago I came across a Board of Trade report from 1929-32. You may know that Homeric's shell plating at the stern came off in 1929 due to fatigue; well, it didn't actually cause any flooding due to her afterpeak -- there was something strange about Homeric's design.

But, there was one small vessel mentioned in the report that had lost plating on one of the two after propeller shaft tunnels like Homeric. She had few bulkheads. Due to watertight door failure (something like that -- at least a failure of watertight integrity) water flooded into her engine room, slowing and then stopping the engines. Flooding increased and she foundered. The Board were so worried about this that although Homeric's design differed they put a watch on her, calling her plating failure an 'unpredented and alarming' development. This was in 1929-30 I think, and there was some trouble in 1932 but apart from that I think she was okay.

Hi Mike!

was it frame 65 or 95? Both numbers seem to be sticking. I guess I'll have to dredge up that tape to double check or do a websearch.

I was quite sure it was 65, but could be wrong of course; it doesn't matter greatly, I guess.

One thing that stands out about bulk carriers is a lot of open space in the cargo area. Nesseccery as the idea is to maximize the ship's cargo carrying capacity...but (You knew this was coming)...there are inhearent weaknesses which just don't go away. With such large and cavernous holds and no decks all the way down, structural strength is going to suffer.

All too true -- the public is fickle about paying high prices for petrol or even commercial raw materials such as iron ore (the late Derbyshire's cargo could have been iron ore -- not sure). If I had *my* way, I'd do something to change that -- not that I would have my way!
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The commercial arguments keep arguing against me -- I guess Edward Wilding and Thomas Andrews felt like that when they were designing the 'Olympic' class in 1908-10. Probably the same for watertight cargo hatches and all of the associated problems -- actually having to get cargo in and out of them!
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I often wonder if Aquitania suffered any problems in her later years from the design of her cargo hatches and areas -- from memory, there were trunked watertight hatches in the forward cargo holds, coupled with *two* watertight decks. Safe sounding, yes, but I dred to think of any flooding above or between those decks! That could have capsized her. I do find her interesting, though Olympic is my favourite -- I may do a biography on Aquitania some time in the future, or at least further my research on her. She was similar to Olympic in many respects and would only have lived to 25-26 years had it not been for the aggressive Adolf. She did live to thirty-six, but not without costs: from 1931 she was showing her age and in 1949 decks and funnels had become paper thin in places due to corrosion. One piece of decking apparently collapsed at the end of 1949, sending a piano through the floor!

Best regards,

Mark.
 
Dec 2, 2000
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Hi Mark, if you have the stability figures for the Aquatania...center of gravity, metecentric hight, etc, you might be able to calculate what it would take to put the ship on her side. I don't know that having flooding high up in the holds alone would be sufficient to do it, but you can bet a lot of people would not have liked the result much.

Cunard seemed to have a predelection for building "tender" ships...at least in regards the Lusitania and the Mauritania. (Not as bad as Balin's designs for the Germans though.) Fortunately, they never learned the hard way!

Cordially,
Michael H. Standart
 
Jan 5, 2001
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Hi Mike!

if you have the stability figures for the Aquitania...center of gravity, metecentric hight, etc, you might be able to calculate what it would take to put the ship on her side. I don't know that having flooding high up in the holds alone would be sufficient to do it...

It would be interesting to get the figures, certainly. I know Cunard specified that her metacentric height should be no greater than that of Mauretania, but unfortunately I don't have the figure and I don't know how to calculate it. Have you any formulae in any of your shipping or marine engineering books? I've quite a few figures of her height, weight, etc.

Best regards,

Mark.
 
Dec 2, 2000
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My Naval arcitecture books do touch on the subject, but I'll have to take them to work with me to find them. A lot of the mathamatical symbology is way over my head. (I should have been more diligent in my studies back in screwal...ah...school.)

Cordially,
Michael H. Standart
 

Erik Wood

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Apr 10, 2001
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I have your formula. I will attempt to put here but it may not work out. Here it is:

New Height of center of gravity above the keel is equal to:

Orginal displacement of ship, and orginal height of center of gravity above the keel

+

weights added or removed and the new height above the keel of the added or removed weight.

DIVIDED by:

the orginal displacement of ship squared.

This I hope helps. If not let me know I have about four other formulas.

Erik
 

Erik Wood

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Apr 10, 2001
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If that one isn't quite right let me know. I looked it up in haste so it could be wrong. I will do a slower more in depth look if needs be.

Erik
 

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