The 'patin catalan' or 'patin a vela' is how we call these boats in Spain.
They are fast, I sail an HC16 with a group of them and there is not big difference.
They can be sailed with strong winds Bft 5 at least.

The spanish class has an active community (mostly in the north-east mediterranean coast) with a regatta circuit equivalent to the 'standard' cats.

A.