In that way it does not. You can move a boat wirh a fan if you use it to blow the air away from the boat to create thrust like a plane. If you direct the fan onto the sail the force of the forward motion will be canceled out by the backwards thrust (if the sail has 100% efficiency which it does not)
A boat with a fan on it can work, because that air bounces off the sail and ends up going backward
In that way it does not. You can move a boat wirh a fan if you use it to blow the air away from the boat to create thrust like a plane. If you direct the fan onto the sail the force of the forward motion will be canceled out by the backwards thrust (if the sail has 100% efficiency which it does not)