Increase velocity of gameObject every time it spawns?

I'm trying to increase the speed of the Ball in a Pong game. I have a score that increases by 1 if the ball crosses a boundary on either the blue and red side. The ball is then spawned to the middle of the game world and the score increase 'till 10 and then pauses. That's what I have so far.

Here's the two scrips associated to the velocity of the Ball:

For the GameEngine:

 using UnityEngine;
 using System.Collections;
 
 public class GameEngine : MonoBehaviour 
 {
     public int bluePoints;
     public int redPoints;
 
     Vector3 velocity;
 
     public Canvas canvas;
 
     // Use this for initialization
     void Start () 
     {
         bluePoints = 0;
         redPoints = 0;
         canvas.enabled = false;
     }
 
     // Update is called once per frame
     void Update () 
     {
         if (bluePoints == 10) 
         {
             Time.timeScale = 0;
             canvas.enabled = true;
         }
 
         if (redPoints == 10) 
         {
             Time.timeScale = 0;
             canvas.enabled = true;
         }
     }
 
     void OnBlueScore()
     {
         bluePoints++;
     }
 
     void OnRedScore()
     {
         redPoints++;
     }
 
     void IncreaseVelocity()
     {
         transform.Translate (velocity * 10 * Time.deltaTime);
     }
 }

And for the Ball:

 using UnityEngine;
 using System.Collections;
 
 public class Ball : MonoBehaviour
 {
     public Vector3 velocity;
 
     public GameObject gameEngine;
 
     public GameObject redPaddle;
 
     public GameObject bluePaddle;
 
     void Start () 
     {
     }
 
     void Update () 
     {
         gameObject.transform.Translate (velocity * Time.deltaTime);
 
         if (gameObject.transform.position.z >= 12.33f) 
         { 
             if (velocity.z > 0)
             {
                 velocity.z = velocity.z * -1;
             }
         }
 
         if (gameObject.transform.position.z <= -12.33f) 
         {
             if (velocity.z < 0)
             {
                 velocity.z = velocity.z * -1;
             }
         }
             
         if (gameObject.transform.position.x <= -15.13) 
         {
             gameEngine.SendMessage("OnBlueScore");
 
             gameEngine.SendMessage("IncreaseVelocity");
 
             gameObject.transform.position = new Vector3 (0, 0.5f, 0);
 
         }    
 
         if (gameObject.transform.position.x >= 15.13) 
         {
             gameEngine.SendMessage("OnRedScore");
 
             gameEngine.SendMessage("IncreaseVelocity");
 
             gameObject.transform.position = new Vector3 (0, 0.5f, 0);
         }
 
     
         if (velocity.x > 0) 
         {
             Bounds bluePaddleBounds = bluePaddle.GetComponent<BoxCollider>().bounds;
             if(gameObject.GetComponent<BoxCollider>().bounds.Intersects(bluePaddleBounds))
             {
                 velocity.x = velocity.x * -1;
             }
         }
 
 
     
         if (velocity.x < 0) 
         {
             Bounds redPaddleBounds = redPaddle.GetComponent<BoxCollider>().bounds;
             if(gameObject.GetComponent<BoxCollider>().bounds.Intersects(redPaddleBounds))
             {
                 velocity.x = velocity.x * -1;
             }
         }
     }
 }