Good points you make about carbon vs steel vs titanium in bike frames. I have put a lot of recent study into the latest developments along these lines. I've hinted around here lately about a project for a boat in Titanium and it is amazing at how many misconceptions there are between a material being strong, stiff, and/or tough.
My client was discouraged for a couple of years from even pursuing a Ti sailboat by the people who brought the project to me. He had worn out a ply/epoxy boat, an aluminum replacement, and is well on the way to wearing out its replacement which was built in composite. What he really wanted was a 'tough' maintenance free (as possible) boat that could be ridden hard and put away wet with a life cycle that would exceed his own. We looked hard at a project done in Ti by the US Navy in conjunction with the National Center for Advanced Materials in Michoud La. (the old NASA facility that did much of the Saturn rocket) and the Bell-Textron (Hovercraft) plant just up the bayou. They got a grant to build a mid-section of a Landing Craft prototype in Ti using friction stir welding and all sorts of the multitude of toys at the old rocketship factory. We considered building our project at Michoud but eventually chose a real world builder who just happens to be very near Bob.
We have been finally getting some positive response from the Coast Guard on the use of the Ti and will be soon doing some lab testing of the welding and scantlings that have been a long and trying process so far.
Here is a video I sent the client early on in the project. Just wanted him to see how we do the scientific process down here on the Redneck Riviera.
Funny thing is that last week he did the same thing to a butt welded hull plate with stringer sample that the builder had sent him. Big honking SIlverado didn't phase it so he went to the boatyard and had the small forklift run over it and the the big forklift do the same with no damage. He finally had the small Travel Lift run over it and the the 100T Travel Lift give it a go. At 15 tons per wheel for the 100T, it finally flattened the stringer but didn't break any welds in the 1/8" Ti.
Next stop, the police firing range!
In the mid 80's there was a NM55 built in Japan using Titanium for the hull. It was to come to California for Transpac, maybe Longy recalls the story,,,,,