Where does AddRelativeForce apply forces?

Hi All, Does AddRelativeForce apply it's force at the CG or the (0,0,0) of the rigidbody? If it claims it will not produce a torque, it has to be at the CG/CM? A rigidbody is flopping over in turns using a buoyancy script. Trying to see if it is the way I apply force. I have lowered the Center Of Mass below the water line but it still does weird rotations in the first 90 degrees of circle. // the force is relative to the rb local corrdinate system bodyToPush.AddRelativeForce( 0.0f, // x : float, 0.0f, // y : float, force, // z : float, ForceMode.Force ); // mode : ForceMode = ForceMode.Force) : void