`WWII Welded Merchant Vessel Structural Failures (Fleet-Wide)`

The 1946 US Navy report data — 4,700 Liberty ships, ~1,000 with fracture casualties, 24 strength-deck fractures, 8 ships lost, 26 lives lost. The USS Schenectady at dry dock and USS Esso Manhattan at sea cited as the canonical photographs. Used to motivate the postwar interest in Griffith's flaw-size theory.

We had a number of problems, and this is the 1946 US Navy report on design and methods of construction of welded steel merchant vessels. It's an investigation the US Navy ran right after World War II, because during the war they built Liberty ships, and they were building some of them from laying the keel to sailing away in 2 weeks at the height of the war. They really learned how to pump them out. They built 4,700 Liberty ships, of which a thousand suffered casualties involving fractures. 24 vessels sustained a complete fracture of the strength deck — the top deck would give strength in bending. One vessel sustained a complete fracture of the bottom, eight vessels were lost. Of these, four broke in two, 26 lives lost. The famous picture of the USS Schenectady sitting at dry dock, never having been out to sea — it just decided to break in two one day, sitting at dry dock. If you go to a fracture book, this is the classic book they usually show. What they don't show is one of the plates from this book of the USS Esso Manhattan, where the same thing happened out in the middle of the ocean, which was a lot worse than doing it at dry dock. They lost a few ships.

The fleet-wide statistical case (4,694 / 970 / 24 / 8 / 4+4 / 26) sourced from the 1946 report. Distinguished from the Schenectady case proper, which is the iconic image; this is the underlying epidemiology.

If you look at the data: 4,694 welded steel merchant vessels were built by the Maritime Commission. These were not all Liberty ships, some were T1 and T2 tankers. 970 suffered casualties involving fractures. By casualty I mean a metal casualty, not a person casualty — though some of them probably suffered the other type too. 24 sustained a complete fracture of the strength deck, one vessel sustained a complete fracture at the bottom, eight vessels were lost, four broken in two, and four were abandoned after fracture occurred. 26 lives were lost in these structural failures.