Freezing a different Object using scripts and GetComponent

Im trying to Freeze a game object either by enabling Kinematic in the ridgidbody of by constraining the Axis via another script with Getcomponent.

public bool TankReady = false;
public GameObject Harvester;

void OnTriggerStay (Collider other){

if (Input.GetKey (KeyCode.F) && TankReady == true){

Harvester.GetComponent<Rigidbody>().isKinematic = true;;

I get no errors but I seem to not get what I want. Any suggestions?

Its actually a bad practice, but maybe try to set rigidbody.velocity to