ALVIN deep research submarine hull transition

Only US titanium submarine ever built; built as Navy prototype program "to learn to weld titanium for bigger ships."

So they had a huge welding institute and they developed technologies like — if you've ever read The Hunt for Red October or seen the movie, they had titanium submarines. My first research project, in 1977, was from the US Navy to weld titanium for submarines. [Tom holds up a 1977-era titanium weld sample.] This probably belongs in the Smithsonian. We were welding 1-inch-thick titanium for submarines. The United States wanted to build titanium submarines. We never built one, other than the deep-sea research vessel Alvin that went down and found the Titanic. The Navy built that as part of a prototype program to learn to weld titanium for bigger ships, because titanium submarines have the same strength-to-weight ratio advantage that aircraft and fast-moving vehicles need. You want high strength-to-weight so you can dive deeper and, hopefully, if you lose power, pop to the surface rather than sink to the bottom — because if you sink to the bottom, everything gets crushed, including the people inside.