Haven't actually sailed in coral bay, but was there about 6 weeks ago.
Spoke to the local CALM officer, and they dont really like you to sail in Bills Bay (the real name of the main Coral Bay)
but if you go around to the next bay where the boat ramp is there is some fantastic flat water sailing to be had there.
also if you head to the north end of the main bay, its pretty much the same.
Just look out for the stingrays, they are bloody enormous