diff --git a/src/main/java/seng302/models/Yacht.java b/src/main/java/seng302/models/Yacht.java
index fae03845..df5a6b20 100644
--- a/src/main/java/seng302/models/Yacht.java
+++ b/src/main/java/seng302/models/Yacht.java
@@ -117,17 +117,38 @@ public class Yacht {
      * @param timeInterval since last update in milliseconds
      */
     public void update(Long timeInterval) {
-        if (sailIn) {
-            Double secondsElapsed = timeInterval / 1000000.0;
-            Double windSpeedKnots = GameState.getWindSpeedKnots();
-            Double trueWindAngle = Math.abs(GameState.getWindDirection() - heading);
-            Double boatSpeedInKnots = PolarTable.getBoatSpeed(windSpeedKnots, trueWindAngle);
-            velocity = boatSpeedInKnots / ClientPacketParser.MS_TO_KNOTS * 1000;
-            Double metersCovered = velocity * secondsElapsed;
-            location = getGeoCoordinate(location, heading, metersCovered);
-        } else {
-            velocity = 0d;
+
+        Double secondsElapsed = timeInterval / 1000000.0;
+        Double windSpeedKnots = GameState.getWindSpeedKnots();
+        Double trueWindAngle = Math.abs(GameState.getWindDirection() - heading);
+        Double boatSpeedInKnots = PolarTable.getBoatSpeed(windSpeedKnots, trueWindAngle);
+        Double maxBoatSpeed = boatSpeedInKnots / ClientPacketParser.MS_TO_KNOTS * 1000;
+        if (sailIn && velocity <= maxBoatSpeed && maxBoatSpeed != 0d) {
+
+            if (velocity < maxBoatSpeed) {
+                velocity += maxBoatSpeed / 15;  // Acceleration
+            }
+            if (velocity > maxBoatSpeed) {
+                velocity = maxBoatSpeed;        // Prevent the boats from exceeding top speed
+            }
+
+        } else { // Deceleration
+
+            if (velocity > 0d) {
+                if (maxBoatSpeed != 0d) {
+                    velocity -= maxBoatSpeed / 25;
+                } else {
+                    velocity -= velocity / 25;
+                }
+                if (velocity < 0) {
+                    velocity = 0d;
+                }
+            }
+
         }
+
+        Double metersCovered = velocity * secondsElapsed;
+        location = getGeoCoordinate(location, heading, metersCovered);
     }