America's Cup 4340 welding procedure development

Used to introduce the hardenability concept. A four-inch-thick keel beam couldn't be made from HY-130 (too soft, plastically deforming in trials) so they wanted 4340, but didn't know how to weld it in that section thickness. Tom showed them how.

Then there's hardenability, which is how deep you can harden it. I was asked once by a professor — would be now mechanical engineering, but at the time he was naval architecture — working on the America's Cup. He had a four-inch-thick keel beam. The keel beam is not just on a big ship; the keel is the thing you build everything up from. There's a keel beam on a 747, a big aluminum beam they build everything up from. But on a sailboat — that particular America's Cup — they had a big steel piece that created the resistance to being blown sideways. This was supposed to be four inches thick.