Most people over rate the actual wind strength. How many times have you heard "it was blowing 20 plus knots out there", but infact the readings were 15knots gusting to 18 knots.

In my opinion 10-12 knots is fantastic sailing for the F16.

12-15 starts getting exciting

15-20 knots gets most skippers to start think about surving the race course

anything over 20 knots and really survival is foremost in most peoples mind.

30 knots is just not fun unless you watching some other fools try and master the conditions.

In Aus, the classes have a wind strength range & generally racing wont occur outside this. 2 - 22knots is the norm.

Spinnakers allways flying downwind unless you have a really steep swell & the waves to close together.(zandvoort?)