# LIberty ship construction question



## Captian Dag (Oct 26, 2008)

following web site has good close ups of Jeremiah O'Brien in Dry Dock. notice the rivits on her hull. I always though Liberties were all welded construction or was it a mix of both?
http://www.jimhafftphoto.com/p312918493/h21353ce4#h34a38626

Kind Regards,
CDag


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## makko (Jul 20, 2006)

Hi CDag,
This is a famous case........When I was about four years old, my father took me onboard one of the Blue Funnel victory ships. My father pointed out the rivetted seam just abaft the wheelhouse , explaining that due to inadequate (or non existent!) stress relieving, the first all welded Liberties either broke in half or developed hull cracks. Thus the one rivetted seam was introduced to add a bit of "give" in the hull's rigidity, avoiding excessive stresses.

The production of the Liberties led to tremendous strides in developing techniques and procedures for welding.
Regards,
Dave


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## Supergoods (Nov 25, 2007)

I seem to recall that there was some riviting in certyain , but not all yards, it may have depended on the availability of skilled riviters.

The riviting appears to be limited to the side plating/frame connections between the turn of the bilge and the load water line.

Nice shot of the weld marks for the paravanes installed during the war in photo 8.

Ian


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## A.D.FROST (Sep 1, 2008)

SD14's(Sunderland built) had rivets in their hull.This was done to fill in holes made by reusable eye pads bolted to the hull from where wires were attached to the drag chains during launching.(Jester)


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## Duncan112 (Dec 28, 2006)

The cracking was investigated by Constance Tipper, the first full time female member of the engineering department at Cambridge University. Even after retirement from full time work she did valuable consultancy work on the welding of the hulls of nuclear submarines 

Bill Hammack has written an excellent appreciation of her..

Every time I ride in a jet, I look out the window and watch the wing. When I see it's still there, I say a silence thanks to Constance Tipper. We take for granted that in our high tech world, things like airplane wings, car axles and buildings stay together, but it hasn't always been this way; that they now stay together is largely because of Constance Tipper. Tipper was born at end of the 19th century and followed a career path unusual at the time for a women. She earned degrees in the sciences, then settled in at Cambridge university to study something that seemed very esoteric. She wanted to know exactly how the arrangement of the atoms in a metal affected its strength and durability. In her lab day after day, she used a special microscope to examine the structure of the metal, then studied how it broke. She did this quietly for nearly thirty years, until she was called to aid her country in its battle with Germany.
The German U-boats were sinking British ships at a rapid rate. Ship builders responded by developed an innovative way to make metal ships. Instead of riveting the slabs of metal, which was time consuming, they simply welded the pieces together. Using this new method they were able to produce a 10,000 ton ship in just forty-two days. During the war the shipyard produced nearly five thousand of these vessels, called Liberty Ships.
Although at first a welcome aid to the war effort, these ships soon became a liability. As they carried crucial supplies across the North Atlantic on the icy Archangel run, the keel of the ship would suddenly crack, as if it had turned to glass. This crack would propagate around the hull until the ship broke in two and foundered at sea.
This called into question whether the rapid welding method should be used. Perhaps, they thought, they should return to the older, slower riveting method. It was at this point that Constance Tipper entered the picture.
The British government appointed a committee to investigate the cause, with Tipper as the technical expert. Tipper, who'd investigated the failure of metals for years, pointed out that the ships fell apart in icy conditions. She acquired pieces of the failed ships, then returned to her lab and showed that under these icy conditions the steel rapidly became brittle, and could then snap like a dry twig. Her work revealed to the ship makers that the fault lay not in the welding, but in the steel. She showed them how to test the steel to ensure the stability of the ships.
With this work Tipper opened up a field called fracture mechanics. Its still used by engineers today to develop wings that don't fall off and car axles that stay attached. So, today as the mechanical world around you doesn't fall apart, give thanks to Constance Tipper.

Copyright 2002 William S. Hammack Enterprises


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## makko (Jul 20, 2006)

Google "riveted seams Liberty ships" and you will find a lot of info. 

Another problem with the advent of all welded construction was the formation of corrosion initiated cracking in the joints between the frames and outer plates. If the weld was unfinished or poorly done, stress concentrations would lead to failure of the weld and either separation of the hull plate or cracking of the same.
I remember that a lot of electric weld sets in shipyards were DC - We had one in Tech to learn the subtle differences between AC and DC "SMAW" welding.
Regards,
Dave


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## kewl dude (Jun 1, 2008)

In 2000 the Liberty Museum ship John W Brown 

http://www.liberty-ship.com/

sailed up the US East Coast from Baltimore then down the St Lawrence Seaway to Toledo Ohio to spend $700,000 having her 14,000 rivets replaced.

http://www.liberty-ship.com/html/pictures/gl2000out.html

Attached 5 of 33 pictures I saved to my machine from this site in 2000. You will find these pictures and many many more on this above URL.

Greg Hayden


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## IAN M (Jan 17, 2009)

*Liberty Ships*



Captian Dag said:


> following web site has good close ups of Jeremiah O'Brien in Dry Dock. notice the rivits on her hull. I always though Liberties were all welded construction or was it a mix of both?
> http://www.jimhafftphoto.com/p312918493/h21353ce4#h34a38626
> 
> Kind Regards,
> CDag


Liberty Ships built by Bethlehem Steel in Baltimore were vertically riveted.

Regards


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