How to do collisions


I am currently making a game where every player controls a ship. This ships should be able to ram each other, taking damage and bouncing off from each other according to there physics material.

Right now every ship is calculating non-authoritativ his own collision and reacting according to that wich results in the first ship hitting the 2nd but the 2nd never touching the first because of minor differences in there physic calculation. Is there a better way. How should i do that?