Wayne.B wrote:
It's written into the sail racing rules that you can't use any ballast
material with a density greater than lead. That rule was implemented
back in the 70s or early 80s to head off several designs that planned
to use depleted uranium as a keel material.

Sure, but that's just for you & me. The big bucks guys make their own
rules. The America's Cup and the IACC pretty much use the rules they
like and ignore the rest. I suspect that given what Stephen B. said,
keel bulbs of tungsten or osmium are simply too expensive & troublesome
even for them. After all, just because you have $70 million to toss away
on a sailboat race, doesn't mean you can spend an unreasonable percent
of the budget just on the keel materials & tooling....

America3 (cubed) had an adjustable column of mercury in her keel for at
least some of the trial races, may have used it in the Cup match for all
I know (and stuff like this is not usually discussed publicly, although
the really good stuff gets to be an open secret). I bet the EPA would
not have liked it, regardles of what the IYRU thinks!

Fresh BReezes- Doug King