For my 100th EpicSki post (took 11 years - I'm a slacker), thought I'd share a spreadsheet I put together when my wife and I were looking for new skis earlier this season. Basically, we wanted better soft snow performance so thought I'd try to calculate how much additional float our new skis might provide. Net-net, I gained ~ 15% float moving from a 163cm Volkl AC3 to a 167cm K2 AfterShock; while my wife gained ~12% moving from a 153cm 2008/2009 Lotta Luv to a 163cm 2010/2011 Lotta Luv. A rough approximation, FLOAT in this instance is ski surface area / skier weight. Not accurate, I know, but close enough for our purposes. So, if my math is correct, is a 12 - 15% gain material? On the snow performance suggests that it is !
The spreadsheet (screen shot below thanks to Cirquerider) approximates ski area by considering it a long rectangle (in blue) flanked by two triangles at tip and tail. That is then divided by skier weight to get an overall FLOAT number expressed in sq mm / pound. Obviously ignores side cut and tip / tail rounding, as well as any lift generated by a moving ski. That said, it was fun to play with and thought I'd post it as I saw a couple of comments from folks wanting to know how different skis might compare in float. In the example below, you can see that in refreshing my wife's 153cm Lotta Luvs we debated whether to go with a 156cm or 163cm. We chose the 163cm to get a boost in float similar to what I got in moving from the AC3s to the AfterShocks - bad karma for me to get better tools than my wife. And yes, I know it's not all about surface area and weight, but that's a reasonable starting point.
Happy to share the Excel file if anyone's interested - just PM me.