400? No way. The number is about 200. Roughly speaking, the first 30 boats or so were built by Dan and Greg as the "Ketterman TriFoiler", then they merged with Hobie and built the remaining ~170 until ceasing production in 1999.
Where? Anybody's guess. Mostly North America, of course, but I know of boats in Hawaii, Australia, and New Zealand in addition to the very interesting European list posted above. Dan's closest to anyone knowing where they all are, and he's long lost track. The boats change hands at the rate of a handful a year, so they gradually trickle out of sight.
Why? Because that's how it is. They kept it in production long enough to prove they could, and to get a solid fell for the volumes the market would consume. In the life of any product the manufacturer has to decide whether the market continues to justify the effort and expense needed to build and sell it, and after six years the TF lost. It's not surprising - it's an expensive,
complicated, specialty craft that not many people will want to commit to. And the scarcity makes it all the more special.
Jonathan Levine
TF#23 "Unfair Advantage"