on a single screw boat what is the normal rotation most boats come with? right hand or left hand rotation?

also, how can you tell if your prop is right hand or left hand rotation?
im pretty sure i know how to tell on the prop, by looking, but what numbers on the prop will tell you?

what would happen to a boat with left hand rotation motor with a rh rotation prop?

might sound like a silly question, but it will put a rest to some pondering ive been doing.
i was under the impression most boats come with rh rotation motors?