An item referred to the magazine Aeroplane dated 5 October 1939 dealing with the use of autogiro’s for protection of convoys. The medium speed of a convoy was usually just between the 10 and 15 miles. Common aircraft were far to fast for escort duties. Autogiro’s however were far more suitable, for instance with a wind power of 15 miles/hour straight ahead a 12 miles speed steaming convoy needed an autogiro a speed of just 27 miles/four to stay in front of the convoy. For a minimum sufficient protection were four autogiro’s needed, at each side one, one ahead and one aft. A merchant ship with the sized of a large coaster and a maximum speed of 15-20 miles was suitable to be used as mother ship. She needed to have enough storage capacity for 12 of those autogiro’s.