Wow - I've managed to stump the panel!!
This picture was taken before the power-wash, so this was as-found after 11.5 months in the water.
Although I like the "sailed too fast" theory, what actually caused this was being stingy to the point of foolishness. When you use a "dry roller" - meaning when you try to stretch your bottom paint coverage, this is what can happen.
of the growth areas show lots of fibers from the paint roller. This provides much more surface area for the grass & critters to attach to, plus the paint is quite thin in those areas. Another gallon of paint and a smarter person driving the roller would have avoided this.
Moral of the story: Don't be foolishly stingy with the bottom paint! Make sure the rollers you use are in good condition - and that you haven't left them uncovered during your lunch break!!
Although I guess we gained at least 1/1000th of a knot
due to less weight on the hull... problem is that advantage disappears after 1 hour in the water due to the growth formation.....