diff --git a/mock/src/main/java/seng302/Model/Polars.java b/mock/src/main/java/seng302/Model/Polars.java
index 4de5b570..2863db48 100644
--- a/mock/src/main/java/seng302/Model/Polars.java
+++ b/mock/src/main/java/seng302/Model/Polars.java
@@ -35,7 +35,6 @@ public class Polars {
         polarValues.put(newKey, boatSpeed);
     }
 
-    //TODO calculate VMG from (windAngle, destAngle, windSpeed).
 
     /**
      * Calculates the VMG for a given wind angle, wind speed, and angle to destination.
@@ -65,27 +64,37 @@ public class Polars {
         ArrayList<Double> windAngles = new ArrayList<>();
         for (Pair<Double, Double> key : this.polarValues.keySet()) {
 
-            windAngles.add(key.getValue());
+            //Don't add angles multiple times.
+            double angle = key.getValue();
+            if (!windAngles.contains(angle)) {
+                windAngles.add(angle);
+            }
         }
 
         //Find the angle with the best VMG.
+        //TODO need to differentiate between windward and leeward.
         double bestVMGAngle = 0;
         double bestVMGVelocity = 0;
         for (double tackAngle : windAngles) {
-            //This is the velocity from the polar table at this wind speed/angle.
-            double estVelocity = this.polarValues.get(new Pair<Double,Double>(polarWindSpeed, tackAngle));
-            double angleBetweenDestAndTack = tackAngle - destinationAngle;
-            //This is the estimated velocity towards the target (e.g., angling away from the target reduces velocity).
-            double vmgTemp = Math.cos(angleBetweenDestAndTack) * estVelocity;
-
-            //Check that the velocity is better.
-            if (vmgTemp > bestVMGVelocity) {
-                bestVMGVelocity = vmgTemp;
-                bestVMGAngle = tackAngle;
+            Pair<Double,Double> key = new Pair<Double,Double>(polarWindSpeed, tackAngle);
+            if (this.polarValues.containsKey(key)) {
+                //This is the velocity from the polar table at this wind speed/angle.
+                double estVelocity = this.polarValues.get(key);
+                double angleBetweenDestAndTack = tackAngle - destinationAngle;
+                //This is the estimated velocity towards the target (e.g., angling away from the target reduces velocity).
+                double vmgTemp = Math.cos(angleBetweenDestAndTack) * estVelocity;
+
+                //Check that the velocity is better.
+                if (vmgTemp > bestVMGVelocity) {
+                    bestVMGVelocity = vmgTemp;
+                    bestVMGAngle = tackAngle;
+                }
+
             }
 
         }
 
+        System.out.println("VMG speed = " + bestVMGVelocity + " , VMG angle = " + bestVMGAngle);//TEMP DEBUG REMOVE
 
         //Create the VMG object and return it.
         return new VMG(bestVMGVelocity, bestVMGAngle);