diff --git a/racevisionGame/src/main/java/mock/model/MockBoat.java b/racevisionGame/src/main/java/mock/model/MockBoat.java
index 24c94531..2a179f7e 100644
--- a/racevisionGame/src/main/java/mock/model/MockBoat.java
+++ b/racevisionGame/src/main/java/mock/model/MockBoat.java
@@ -207,15 +207,23 @@ public class MockBoat extends Boat implements Collider {
     }
 
     @Override
-    public boolean rayCast(MockBoat boat) {
+    public boolean rayCast(MockBoat boat, Collision collision) {
         double distance = GPSCoordinate.calculateDistanceMeters(boat.getCurrentPosition(), this.getCurrentPosition());
-        Bearing bearing = Bearing.fromAzimuth(GPSCoordinate.calculateAzimuth(boat.getCurrentPosition(), this.getCurrentPosition()));
-        if(distance < 100 && boat != this) {
-            onCollisionEnter(new Collision(bearing, distance));
+        Bearing bearing = GPSCoordinate.calculateBearing(boat.getCurrentPosition(), this.getCurrentPosition());
+
+        if(distance <= collision.getDistance() && (int)bearing.degrees() == (int)collision.getBearing().degrees()) {
+            onCollisionEnter(collision);
             return true;
         } else return false;
     }
 
+    @Override
+    public boolean rayCast(MockBoat boat) {
+        if(boat != this) {
+            return rayCast(boat, new Collision(Bearing.fromDegrees(0), 100));
+        } else return false;
+    }
+
     @Override
     public void onCollisionEnter(Collision e) {
         System.out.println(e.getBearing().degrees());
diff --git a/racevisionGame/src/main/java/mock/model/collider/Collider.java b/racevisionGame/src/main/java/mock/model/collider/Collider.java
index a443d3f9..479cfc2f 100644
--- a/racevisionGame/src/main/java/mock/model/collider/Collider.java
+++ b/racevisionGame/src/main/java/mock/model/collider/Collider.java
@@ -7,7 +7,15 @@ import mock.model.MockBoat;
  */
 public interface Collider {
     /**
-     * Indicates whether a ray cast from a boat to a target collider triggers a collision.
+     * Indicates whether a ray cast from a boat to a target collider triggers a collision with the specified parameters.
+     * @param boat potentially colliding with target
+     * @param collision parameters of valid collision
+     * @return whether or not a collision has occurred
+     */
+    boolean rayCast(MockBoat boat, Collision collision);
+
+    /**
+     * Indicates whether a ray cast from a boat to a target collider triggers a collision. Parameters are set by the object.
      * @param boat potentially colliding with target
      * @return whether or not a collision has occurred
      */
diff --git a/racevisionGame/src/main/java/mock/model/collider/ColliderRegistry.java b/racevisionGame/src/main/java/mock/model/collider/ColliderRegistry.java
index e58a28f1..59eb742b 100644
--- a/racevisionGame/src/main/java/mock/model/collider/ColliderRegistry.java
+++ b/racevisionGame/src/main/java/mock/model/collider/ColliderRegistry.java
@@ -34,6 +34,11 @@ public class ColliderRegistry implements Collider {
         for(Collider collider: colliders) addCollider(collider);
     }
 
+    @Override
+    public boolean rayCast(MockBoat boat, Collision collision) {
+        return false;
+    }
+
     @Override
     public boolean rayCast(MockBoat boat) {
         for(Collider collider: colliders) {
diff --git a/racevisionGame/src/main/java/shared/model/CompoundMark.java b/racevisionGame/src/main/java/shared/model/CompoundMark.java
index f8080c8d..1787562d 100644
--- a/racevisionGame/src/main/java/shared/model/CompoundMark.java
+++ b/racevisionGame/src/main/java/shared/model/CompoundMark.java
@@ -5,11 +5,6 @@ import mock.model.MockBoat;
 import mock.model.collider.Collider;
 import mock.model.collider.Collision;
 
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.List;
-
 /**
  * Represents a compound mark -  that is, either one or two individual marks which form a single compound mark.
  */
@@ -151,16 +146,25 @@ public class CompoundMark implements Collider {
     }
 
     @Override
-    public boolean rayCast(MockBoat boat) {
+    public boolean rayCast(MockBoat boat, Collision collision) {
         GPSCoordinate position = boat.getCurrentPosition();
         double distance = GPSCoordinate.calculateDistanceMeters(position, closestMark(position).getPosition());
-        Bearing bearing = Bearing.fromAzimuth(GPSCoordinate.calculateAzimuth(position, closestMark(position).getPosition()));
-        if(distance < 100) {
-            onCollisionEnter(new Collision(bearing, distance));
+        // Compass direction of collider
+        Bearing absolute = Bearing.fromAzimuth(GPSCoordinate.calculateAzimuth(position, closestMark(position).getPosition()));
+        // Direction of collider from heading
+        Bearing relative = Bearing.fromDegrees(absolute.degrees() - boat.getBearing().degrees());
+
+        if(distance <= collision.getDistance() && (int)relative.degrees() == (int)collision.getBearing().degrees()) {
+            onCollisionEnter(collision);
             return true;
         } else return false;
     }
 
+    @Override
+    public boolean rayCast(MockBoat boat) {
+        return rayCast(boat, new Collision(Bearing.fromDegrees(0), 100));
+    }
+
     @Override
     public void onCollisionEnter(Collision e) {
         System.out.println(e.getBearing().degrees());
diff --git a/racevisionGame/src/test/java/mock/model/MockBoatTest.java b/racevisionGame/src/test/java/mock/model/MockBoatTest.java
index b1ee551c..61762192 100644
--- a/racevisionGame/src/test/java/mock/model/MockBoatTest.java
+++ b/racevisionGame/src/test/java/mock/model/MockBoatTest.java
@@ -1,7 +1,37 @@
 package mock.model;
 
+import mock.model.collider.Collision;
+import org.junit.Before;
+import org.junit.Test;
+import shared.model.Bearing;
+import shared.model.CompoundMark;
+import shared.model.GPSCoordinate;
+import shared.model.Mark;
+
 import static org.junit.Assert.*;
 
 public class MockBoatTest {
-//TODO
+    private MockBoat boat;
+    private CompoundMark ahead;
+    private CompoundMark behind;
+
+    @Before
+    public void setUp() {
+        boat = new MockBoat(0, "Bob", "NZ", null);
+        boat.setCurrentPosition(new GPSCoordinate(0,0));
+        boat.setBearing(Bearing.fromDegrees(180));
+
+        ahead = new CompoundMark(0, "Ahead", new Mark(0, "Ahead", new GPSCoordinate(-.0001, 0)));
+        behind = new CompoundMark(1, "Behind", new Mark(0, "Behind", new GPSCoordinate(.0001, 0)));
+    }
+
+    @Test
+    public void markAheadOfBoat0() {
+        assertTrue(ahead.rayCast(boat, new Collision(Bearing.fromDegrees(0), 100)));
+    }
+
+    @Test
+    public void markBehindBoat180() {
+        assertTrue(behind.rayCast(boat, new Collision(Bearing.fromDegrees(180), 100)));
+    }
 }