Right, but what if you're welding a 40ft long plate to another 40ft long plate? You need to cover a large portion of both the front and back in argon. At some

Right, but what if you're welding a 40ft long plate to another 40ft long plate? You need to cover a large portion of both the front and back in argon. At some point it becomes easier to instead of constantly rigging up and tearing down back-shields to just put up a huge tent, bring all the various sub-assemblies in there and weld everything up. You don't have to keep the whole sub in the tent from start to finish, just while you're assembling all the various small parts into the large overall hull. If it's a 3 year build, I'd guess you'd only need it that way for a few months. Also 12 million pounds of steel would cost you less than $12 million. And that's before you have to machine, cut, fit, weld, anything. All of those things get much, much more expensive when you're talking Ti. I suspect that an order of magnitude across all aspects is reasonable, for material cost, machining cost, welding cost, etc. So if you had $10mm of steel and $100mm of fabrication for the Seawolf hull, you'd have $100mm of Ti and $1b of fabrication for the all titanium sub.