canseetarget how to?

Hey guys how can i get the canseetarget to work with the beaming range and also that it wil pick the closest Enemy in range? the apply damage is also not working . does someone know how this is done?

using UnityEngine; using System.Collections;

public class PlasmaBeamWeaponRight : MonoBehaviour{

 public GameObject plasmaBeam;
 public float spawnTime = 5f;
 //
 public Transform target;
 private bool CanSeeTarget;
 public float BeamingRange = 500f;
 //
 private LineRenderer lineRenderer;
 private float counter;
 private float dist;
 //
 public Transform origin;
 //
 public float linrDrawSpeed = 6f;
 public float damage = 100.0f;
 RaycastHit hit;

 // Use this for initialization
 void Start()
 {

 }

 // Update is called once per frame

 void OnCollisionEnter(Collision col)
 {

     col.gameObject.BroadcastMessage("ApplyDamage", damage = 100.0f);

 }

 void LateUpdate()
 {

     target = GameObject.FindWithTag("Enemy").transform;
     origin = GameObject.FindWithTag("originR").transform;
     if (target != null)
         //
     lineRenderer = GetComponent<LineRenderer>();
     lineRenderer.SetPosition(0, origin.position);
     lineRenderer.SetWidth(.45f, 0.2f);

     dist = Vector3.Distance(origin.position, target.position);
     if (counter < dist)
     {
         counter += .1f / linrDrawSpeed;

         float x = Mathf.Lerp(0, dist, counter);
         dist = Vector3.Distance(origin.position, target.position);
         lineRenderer.SetPosition(0, origin.position);
         Vector3 pointA = origin.position;
         Vector3 pointB = target.position;

         Vector3 pointAlongLine = x * Vector3.Normalize(pointB - pointA) + pointA;

         lineRenderer.SetPosition(1, pointAlongLine);
         Vector3 fwd = transform.TransformDirection(Vector3.forward);
         if (Physics.Raycast(transform.position, fwd, 0))
             hit.transform.SendMessage("ApplyDamage", damage, SendMessageOptions.DontRequireReceiver); //Call the method Apply Damage in the gameobject that is hit
     }
 }

}