follow an object's x-axis and have it translate smoothly into another object's z-axis rotation

Questions & Answers
1

I'm making a 2.5 side scroll game. Game objects are 3D but the game is essentially 2D.

I have Ship B tracking Ship A's position along the x and y axis. When A moves past B in the side-scroll , I want B to Rotate around it's Y-axis as it is tracking A's movement.

I have script that does this but the Rotation around Z-axis is instantaneous. I need to slow it down to A's speed as it passes B from left to right. Sort of how an helicopter banks to make a turn. I don't need realism, Just need a smooth movement to show Ship B's 3D profile. 

 public class LookAtTarget : MonoBehaviour
    {
        public Transform target;

         void Update()
         {
         float lockPos = 0;
    {
         transform.rotation = Quaternion.Euler(lockPos, transform.rotation.eulerAngles.y, lockPos);
    }

              if(target != null)
              {
                   transform.LookAt(target);
              }

         }
    }
2

Something like this may work *note not tested javaScript code

var rotationSpeed = 5.0; 
var theTarget : Transform;  

function RotateTowards (position : Vector3) {

        var direction = position - transform.position;
        direction.y = 0;
        if (direction.magnitude < 0.1)
            return;

        // Rotate towards the target
        transform.rotation = Quaternion.Slerp (transform.rotation, Quaternion.LookRotation(direction), rotationSpeed * Time.deltaTime);
        transform.eulerAngles = Vector3(0, transform.eulerAngles.y, 0);
    }

And call it like so:

RotateTowards(theTarget);