Why can't i serve overhand?

Answer 1

No you don't have to in fact, former French Open champion Michael Chang often resorted to the underhand serve. But the overhand serve is greatly recommended as more power is achieved when hit overhand.

Answer 2

Because you have a higher chance of getting the ball out of control and eventually damaging SOMETHING. My brother, my cousin, and I were playing outside on the beach and my cousin served it overhand and got the ball stuck in the Lifeguard Tower!!

Answer 3

yes but it must go over the net in a diagonall direction