It is a new format that was first tried at the Alter Cup that I was regatta chairman at out of ABYC.
There is not the boat rotation at is prepared at the beginning of the event. Instead you take the bottom three teams from A Fleet and move them to B Fleet and the top three teams of B Fleet and move them to A Fleet. The first race of the regatta you take the top 5 teams in each randomly selected fleet and put them in A Fleet and the bottom 5 from each and put them in B Fleet.
Scoring will be finishes in each flight. A Fleet will get 1 through 10 and B Fleet will get 11 through 20.
This is a great format because you are sure to get the best sailors always sailing against the best sailors. Not so much the luck of the draw when you get put into a flight.
The trick is getting instant justice on the beach so you can send the next Fleet to the start line. If there is a protest or a redress that has to be hear before you can determine who is going sailing in the next race.