They might - to be honest thee is a bit more to it than that ............. it depends where on the hull you fit them and how the boat is balanced to start with. If you use bow lifting props to get the speed up, then putting them right at the back on the inside spray rails would be the best place for them, or if you use stern lifting props like a bat boat further forwards would have more effect. I would say it would be the last thing after getting the best out of a boat with props, balancing a boat etc (sticking things to the bottom of the boat is a bit of a job!) - however I'm sure someone will have a different view!
Don't forget if it's still a leisure boat that it will make the ride harder, make it harder work to drive in the rough (too much lift and the boat will "fly" more), and they get in the way getting on and off the trailer. Oh yeah and if we fit them it's expensive!