During the 1940s, the U.S. needed to build cargo ships faster than ever before. To save time, engineers switched from traditional to welding . On paper, the steel (Grade A) had sufficient tensile strength to handle the heavy cargo and rough seas.
The ships were built with square hatch corners. In strength theory, a sharp corner acts as a "stress riser." While the average stress on the hull was low, the localized stress at those 90-degree corners was high enough to initiate cracks. Applied Strength of Materials
However, the ships began to fail catastrophically. In some cases, a ship would literally snap in half while sitting at the dock or sailing through the freezing North Atlantic. The "Applied" Engineering Reality During the 1940s, the U
In a riveted ship, a crack usually stops when it hits the edge of a plate. In a welded ship, the entire hull is one continuous piece of metal. Once a crack started at a square corner in cold water, it could zip around the entire hull at the speed of sound. On paper, the steel (Grade A) had sufficient