The manufacturing and production of the World War II Liberty Ships: The liberty ships were launched in 1941, the ugly ducklings are the famous name of the liberty ships that named by President Roosevelt. Liberty ships were produced by welding that was faster and cheaper than riveting. Liberty ships were fifty-seven feet (wide), slightly over forty-four hundred feet (long), used a steam engine with 2500 horsepower. The liberty ships were one of the more important contributions to victory in World War 2. When the united states realized that if England destroyed, the united states will lose their allies in Europe. So, the urgent need for a good number of ships came and President Roosevelt predicted that these liberty ships will restore the liberty to his allies and the victory in Europe. About three thousand of liberty ships were built in a very short time, about seventy days were sufficient to build the first liberty ship, but the short period led to the deficiency in the ship design and consequently, many ships lost because of steel failures. Slightly more 1200 of liberty ships suffered from fatal problems then it’s lost. Also, 3 ships were lost because of other industrial defects (split in half). The production and the construction techniques that used in liberty ships were transformed from the labour-intensive practice of riveting to the welding of hull plates, that affects positively in the ship’s hull. The most of liberty ships were an example of the brittle fracture of steel, the failure of these ships led to review the structural damages that observed in the decks and hulls. Some of these structural and metallurgical defects were from the corner of each hatch (i.e., door) was square; these corners acted as points of stress concentration where cracks can form. Weld defects and discontinuities (i.e., sites where cracks can form) were introduced by inexperienced operators. Some of the testing methods that could have to detect these failures are to install crack-arresting devices such as riveted straps and strong weld seams to stop propagating cracks. The immediate actions were taking to resolve the structural and metallurgical failures are Lowering the ductile-to-brittle temperature of the steel to an acceptable level by improving steel quality (e.g., reducing sulfur and phosphorus impurity contents) , improving welding practices and establishing welding codes and rounding off hatch corners by welding a curved reinforcement strip on each corner. There are two liberty Ships still in service and sailing nowadays. The first one is the O’Brien in San Francisco and it was used ”represented in its engine” in Titanic film by James Cameron in 1997. The other liberty ship is S.S. John W.Brown which open to the public and used in cruises a couple times in the year. Henry J. operated the majority of liberty ships (about 1552 ships), came from new yards constructed and produced on the west coast. This research gathers important information about the liberty ships through its function during World War II, the construction methods and clarify the importance of these ships in this era. This research also, help me in my future career in welding through the structural and metallurgical defects that found in the liberty ships and the learned the testing methods that used in solving these structural and metallurgical defects.