The bad news: I found a bug that stops you from creating private leagues before the event starts!
The good news: I've found a workaround!
Click on the links below to be taken to the regatta pages where you'll be able to create/join leagues:
The Vets/Lwt Boat Race
The Boat Race
California Classic
There isn't the ability to create a private league for a series yet but it's already been requested multiple times so I'll put it on the list!
