John Coxon starts off as an aeronautical engineer, with ideas for self pitching propellors for aircraft: including fixed wing and helicopters. John Coxon then uses these ideas Woodcoxon Engineering Limited to patent self-pitching propellors for marine craft. Converting the old Petworth bus garage into a propellor foundry, he floods at least one of the vehicle inspection pits to make it into a water-tunnel for testing the propellors