http://files.filefront.com/Dick+OKan.../fileinfo.html
Here you go, and yep, courtesy of Rockin Robbins. I would suggest this to all.
No real skipper should be without the ability to perform this technique and he shows you step by step how to do it. It's also a good example of usage for plotting tools. I ecspecially love it's not the perfect execution, but you certainly get the idea of how to execute the method
ARR! Thanks to R.R. !