THE PILOT'S FAILURE TO FOLLOW PROCEDURES AND DIRECTIVES WHICH RESULTED IN THE FAILURE OF THE PILOT TO RECOGNIZE THE STOPPAGE OF THE REAR ENGINE PRIOR TO TAKE OFF. ADDITIONALLY THE LACK OF TOTAL ENGINE POWER RESULTED IN THE INABILITY OF THE PILOT TO MAINTAIN THE PROPER CLIMB SPEED, AND RESULTED IN A SUBSEQUENT FORCED LANDING IN WATER. FACTORS RELATED TO THE ACCIDENT WERE THE PILOT'S FAILURE TO COMPLY WITH THE MANUFACTURER'S SERVICE LETTER PERTAINING TO THE OPERATIONAL PROCEDURES TO PREVENT A REAR ENGINE POWER LOSS, AND THE PILOT'S TOTAL LACK OF FLYING EXPERIENCE IN THIS TYPE OF AIRPLANE.