The Australian VYC yardstick rating can help us out here.

F16 slp + spi = about 71.7
F16 uni + spi = about 74.1

Hobie 16 = 81

I-14 = 86.5
49-er = 83.0

The 49-er is actually the fastest skiff in the listing.

Only a 18 foot skiffs can be expected to be faster. From memory they were rated around 70 = equal to F18 and old standard Tornado, but then again these boats are sailed by professional crews.

Everything seems to point to the fact that cats are just noticeably faster; which is my own experience sailing the 49-er as well. I'm sure that "old skiffy now F16 sailor" Paul Kilkenny will back me up here. Paul ?

Wouter