The Ships America Built Faster Than U-Boats Could Sink Them

How were Liberty ships built so fast in WW2, and why did some of them break in half? In 1942 U-boats were sinking more than three Allied ships a day; America answered with an old British tramp design, a triple-expansion steam engine and hundreds of thousands of new workers in the Kaiser shipyards, welding ships together like a kit until the yards launched about three a day. We take a Liberty ship apart in 3D, from the engine to the square hatch corner where the cracks began, and follow the brittle fracture of steel that changed in the cold, and the fix they had thrown away. Operation Drumbeat and the ships burning off the American coast; the Maritime Commission's order; the British mission and the Sunderland tramp; Henry Kaiser; "a dreadful looking object" and the ugly duckling; the Patrick Henry and Liberty Fleet Day; how a triple expansion steam engine works; Richmond, the women welders and the Swan Island nurseries; prefabricated blocks; the Robert E. Peary in four days and fifteen hours; the Schenectady breaking in two at the dock; the Thomas Hooker; the Charpy test and the ductile-to-brittle transition; Constance Tipper; why a ship is a beam and a square corner is a notch; rounded hatch corners and riveted crack arrestors; the Stephen Hopkins; the merchant mariners; the SS Richard Montgomery and her masts; and the SS Jeremiah O'Brien, still sailing. Your guess first: how many days do you think it took to build one Liberty ship? The answer is in the video. Chapters: 0:00 Three a day 1:11 The arithmetic of losing 2:33 An old British tramp 4:29 The engine 6:03 Building ships like cars 8:35 The night at Swan Island 10:02 The steel that changed in the cold 11:52 One square corner 13:53 The fix they had thrown away 15:02 What they carried 16:28 The last of the Liberties Sources: ASME, Liberty Ship EC2-S-C1, SS Jeremiah O'Brien, National Historic Mechanical Engineering Landmark (1984); NPS, SS Jeremiah O'Brien National Historic Landmark nomination; the SHIPS Project (the 1942 engine manual) TWI, "Schenectady T2 tanker" (the Board of Investigation's figures); Ship Structure Committee reports (SSC-16, hatch corner tests; Gabriel and Imbembo on notch toughness); The Mariners' Museum, "Brittle Fracture: When Ships Split in Two" B. Potter, "How the US Built 5,000 Ships in WWII", Construction Physics (after F. C. Lane, Ships for Victory, 1951); Naval Gazing, "Liberty Ships" parts 1-3 NPS Rosie the Riveter WWII Home Front NHP; Oregon Historical Society and the Oregon Encyclopedia (Kaiser shipyards, Swan Island); Kaiser Permanente history uboat.net (Operation Drumbeat, ships hit by month, the Thomas Hooker); FDR's address for Liberty Fleet Day (American Presidency Project); Cambridge Department of Engineering (Constance Tipper) Maps: Natural Earth. The 3D models and diagrams are reconstructions (hatch sizes are estimates, and the bending of the hull on the waves is drawn larger than life so it can be seen); figures that sources give differently (losses off the US coast, the number of ships that cracked) are given as approximations. A like and a subscribe help me take apart more of history's machines for you:    / @howitticked   #libertyships #ww2 #shipbuilding