Mine is this:
http://www.antiquark.com/sliderule/s...lide-rule.html
Well, not virtual, real one. Yes, since its S scale is 6 - 90, I need to perform simple subtraction for anything beyond 90 but that won't hurt much; it's maybe alternative to "Brain Age" on Nintendo DS :p And knot - km conversion is simple... the most fundamental usage of sliderule is multiplication and division, anyway
