Okay, here goes...

In CCup Race 3, ZEPHYR's elapsed time was 59m21s on a 5.0nm W/L course. That equates to 712.2 spm.

So, on a plot of ZEPHYR's performance curve for a W50L50 course, 712.2 spm indexes to 12.570 kts of "Indexed Wind". That Indexed Wind is compared to the other boats in her class and, being the highest, she is the winner!

That's it, very simple. (I'll attach the CCup race results in the next message.)

Kett