They do that on a lake just south of me in Il.
Kinda cool. They start 3 wide at the beach with skis in the water. When the grean flag drops skis come up and preaty much stay there untill the race is over and they are back on land (unless something goes wrong). Three sleds to a race on a twin oval (small oval inside a big one with one common corner). They run the big oval but each driver has to take one turn on the small oval in numbered order with your start position. That feature preaty much assures that sleds will be passing eachother at some point which makes it more interesting. Looked like great fun but did get boring to watch after a few races.
opsled