Fact sheet:Liberty ships.

[pelthunter]

But her stuff, if it was that important, would have found its way into the Fleet Program.

Well, as it is basis for what is known these days as the "Tipper test", it did find it's way into shipbuilding in a big way.

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ORIGINAL: Symon

ORIGINAL: tocaff
A high school friend's father bought and ran 4 surplus Liberty ships between New York (cargo was coal) and Rio (cargo was lumber). I was invited to work one summer and was tempted, but didn't bite.

You should have. I grew up with Lyke's in Tampa. I learned about the sea from them. Went to Europe when I was 12 on Adabelle Lykes. Yikes. JWE

Probably Adabelle Lykes (2) then? Former Cape Tryon?

Seems like if it's a 44 ship you didn't have to worry much. [:)]

[Symon]

ORIGINAL: pelthunter
Well, as it is basis for what is known these days as the "Tipper test", it did find it's way into shipbuilding in a big way.

There is no such thing, neither in shipbuilding, nor in metallurgy, known as the Tipper Test. You have been spending way too much time on the Internet.

The temperature based loss coeficient for material ductility has been part of the CRC Handbook for maybe 80 years. She had a good part to play in the reduced temperature coefficients in the late '40s early '50 time frame. It has nothing whatever to do with Liberty ships, so I wonder what your point is.

[ed] didn't find its way into shipbuilding in either a big or small way. Last time I looked, in 2007, it wasn't even on the radar. Must have been really important.

[KenchiSulla]

Very informative Symon, thanks

[dr.hal]

There was (still is?) a liberty ship that was an operating museum out of New Orleans a few years ago.... I think one of the few still operational... painted gray and everything! I've not been back here long enough to find out is she is still around.

[pelthunter]

Charles, Jim and Gerry Smith. "Constance Tipper: her life and work", Materials World 1996

Hayes, Evelyn. "Dr. Constance Tipper: testing her mettle in a materials world", Advanced Materials & Processes 1998

Cotterell, Brian. Fracture and Life. Imperial College Press.

Boyd G M (ed.) Brittle Fracture in Steel Structures.

"""“Give me liberty or give me death” said President Roosevelt at the launch of the first of a new, quick-build class of ships in September 1941. From then on known as Liberty Ships, these cargo vessels were used to carry supplies from the USA to the UK and Russia during World War II. However, they had a major problem. Fracture in the hulls of the welded (rather than riveted) ships, often caused the ship to break in two and leading to huge loss of life and cargo.

Women made many contributions to the war effort and Constance Tipper was no exception. Her discovery in Cambridge University’s engineering department was vital to solving the problem with the Liberty Ships and is still used in building and engineering today.

Tipper found that the cause of the fractures in the ships was not, as many thought, due to the welding, but because of the steel itself. She discovered that in the cold of the North Atlantic, the type of steel used for the ships became brittle, rather than ductile (able to bend or deform) hence the cracks. Thanks to her work, modifications were made to the ships allowing the vital supply route to remain open throughout the war. She was also the first person to use a scanning electron microscope to examine metals, and developed the Tipper Test which is still used to determine the brittleness of steel used in construction and manufacture.

Constance Tipper was a pioneering woman in a man’s world - she was the only female full member of the Faculty of Engineering, and continued consultancy work in the Barrow shipyards until well into her seventies. She is commemorated in Cambridge by a tree planted on her 100th birthday at her old college, Newnham.""" - Cambridge Science Centre


I made exceptional effort to understand why one would try to deny existing fact and disclaim well documented history. I failed.

[rustysi]

Thought Victory was a separate class - later than the Liberty

Yeah, although not very well put my point was that all these vessels tended to be lumped together as Liberty ships when IIRC correctly there were more Victory ships built. They were still referred to as Liberty by most.

often caused the ship to break in two and leading to huge loss of life and cargo

Notheing I've read in about 50 years has stated this to be true. While it did happen I've never encountered often, or hugh loss. Of course from my perspective even one is unacceptable, but the problem was due to unforseen circumstances as stated above. Also as stated above the situation was corrected.

[wdolson]

The Victory ships were an improved Liberty ship. I would call them a different class, but they were on the same family tree.

I think a lot of people who aren't all that well versed on ships, especially merchant ships tend to lump the two together because they can't really tell the difference.

Bill

[pelthunter]

12 ships are quoted for being sunk due to hull brittleness, three of them being Liberty class.

That would be guesstimated loss of 200 merchant mariners, cargo and passengers over and above that.

[rustysi]

three of them being Liberty class.

And weren't there somewhere in the neighborhood of 2700 Liberty/Victory ships built (IIRC). Unfortunate that it happened but I'd not describe it as often or hugh.

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ORIGINAL: rustysi

three of them being Liberty class.

And weren't there somewhere in the neighborhood of 2700 Liberty/Victory ships built (IIRC). Unfortunate that it happened but I'd not describe it as often or hugh.

You might be surprised by the number of ships affected, if not sunk outright. I was! [:)]

http://www.sozogaku.com/fkd/en/cfen/CB1011020.html

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It's been interesting reading tonight. Here's a pretty authoritative article (excerpt).

[rustysi]

Interesting.

[bobsteele]

USS Liberty was a converted and updated Victory class. Badly damaged by the Isrealis during the 6 day war.

Victories ware bigger and faster than Liberties. Not many are still around. One is in Long Beach. I kick myself every time I go visit my sister in Long Beach (she lives in the marina there) that I don't make a day of it and visit Lane Victory and Iowa since they are both about a mile from her boat.

[BattleMoose]

Using welding to join ships together was largely first done with the Liberty ships. Before construction was with rivets. Why this is an important distinction is that riveted construction consists of many different pieces of steel joined together. While welded construction essentially is a singular piece of steel.

And the nature of ships on the ocean is going up and down a lot(duh) but this results in a very repetitive stress on the vessel. And where there is a flaw in the construction (There are always flaws) a crack can develop and grow. With each compression of the vessel hitting the ocean after cresting a wave and so forth, the crack will grow. At some point, the metal just cannot take it any more and the crack will propagate extremely quickly, like, faster than the speed of sound quick. The crack can continue through the entire length of the steel. Which for a liberty ship, is the entire ship. For other riveted vessels, its just that singular riveted piece of steel and doesn't pose nearly the same kind of threat.

When liberty ships were built, none of this was understood or even known. A new technology was used in a way that wasn't done before. If tougher steel was used, it would have been less of a problem. If there were less flaws in the steel it would have been less of a problem. If the oceans weren't so cold it wouldn't have been a problem. If the ship wasn't welded it wouldn't have been a problem, it was the combination of all these factors that caused the failures. And it was effectively the same type and kind of steel that was used before. Just no one ever cared when a crack grew in a riveted piece of steel on a merchant man, just patch it up and been on your way.

Its worth noting that the failures of the Liberty ships, effectively birthed the branch of engineering called "Fracture Mechanics". Indeed any introductory lecture on Fracture mechanics includes the discussion of liberty ships.

http://en.wikipedia.org/wiki/Fracture_mechanics

As examples.
http://m-5.eng.uml.edu/22.311/s2011/pow ... 011-v1.pdf
http://moodle.technion.ac.il/pluginfile ... _ships.pdf

This type of failure by crack propagation is also what brought down the comets. Their square windows created a very strong stress point on which cracks could easily grow.

[rustysi]

USS Liberty was a converted and updated Victory class. Badly damaged by the Isrealis during the 6 day war.

Not talking about an individual ship, but the class. All ships of that class are referred to as Liberty's.

[m10bob]

After the war, Kaiser (who made many of these ships) began making automobiles. My dad had one. The trunk lid opened, which included the rear window, like a huge hatchback.
He was able to carry all the rifles and their racks for an entire company to the range in that thing.

[Symon]

ORIGINAL: BattleMoose
Using welding to join ships together was largely first done with the Liberty ships. Before construction was with rivets. Why this is an important distinction is that riveted construction consists of many different pieces of steel joined together. While welded construction essentially is a singular piece of steel.

No, Moose, it was not. C'mon, welding was done on subs and DDs and bears, oh my, since the 30s.

[wdolson]

The first welded merchant ship was built in 1930. Some experiments in welding warships had been done earlier:

http://www.weldinghistory.org/whfolder/folder/wh1900.html

[BattleMoose]

Ah, it appears so. While the Liberty ships do not have that distinction, it was still a very new method for ship fabrication. That there were unknowns in the performance, should not be surprising.