Frostbiters

I noticed these sailboats as I was wandering around looking for photo opportunities.
I asked a man walking his dog about them.

Me: Isn't it a bit chilly to be out sailing?
Man: Yup. Frostbiters
Me: Oh... so they do this once a year?
Man: Nope. Every Saturday.
Me: You wouldn't catch me out there on a sailboat today. It's freezing!
Man: Yup. I don't get it myself.