A 'School' of Sailboats

Though they look kind of like butterfly wings moving across the water, butterflies move too randomly for this metaphor.  And what do you call a group of butterflies?  These little sailboats look more like a school of fish.

I have enjoyed watching these classes numerous times over the last three days on Eagle Harbour at Bainbridge Island.  It was fitting that they be heading out to class as we departed.

So teeny, they hold a single person.  They move mostly in unison as they follow the wind.