Three Sisters is the name of the boat that 3 different molds were taken from. One kept the same dimensions, one had a higher sheer and the third had a larger propeller opening. I've forgotten which one is which in the shuffle of time. I think the Crooked River 28 is the same as the NB 28, I might be mistaken though.
Three Girls, a wooden boat used for a plug to create the Wayne Beal 28 (now the Muscle Ridge 28), the Calvin Beal 28 (I think) and the Mitchel Cove 28 which became the Crooked River 28 which became the Northern Bay 28.
To the best of my knowledge and as complete as my notes have in them.