RCU Forums - Help selecting prop?

Hello I'm new here and to the hobby of rc boating. I'm building a brushless setup in a catamaran hull I have it's fairly small at about 16.5 inches in length , I have a 60amp seaking ESC paired with a seaking 3900kv motor coming in the mail. I plan on running it with a 3s lipo if that's too much I will use 2s. I'm having trouble finding the a correct size propeller for my boat (I'm pretty much clueless about props) it would be great if one of you could kindly help me find what size and pitch prop I would need for my setup.

Thanks