STIRLING! STIRLING! STIRLING! Okay, my bad. I've been talking about AIP [Air Independent Propulsion] systems for submarines, using 'sterling' engines. Well, I just figured out that they're spelled STIRLING! Duh.... <g> Of course, I was spelling (and pronouncing) "tetrahedron" (as in "tetrahedron kite") as "tetrahedon" for a long time, too.... -Allan