On 3 April 1941, a second plan was issued to modify NA-NCF-44 in such a way as to make it applicable to the concept of war outlined in "RAINBOW No. 1." This modification was entitled, North Atlantic Naval Coastal Frontier Plan O-4 (RAINBOW No. 1), with the short title, NA-NCF-42. On 22 April 1941, a third plan was issued: the original Operation Plan for the Forces of the North Atlantic Naval Coastal Frontier. This plan was designated, "Operation Plan, NA-NCF-1-41." Because of the restricted nature of problems concerned with the organization of task forces and task groups within a naval coastal frontier, this aspect is considered in a separate section. It may suffice to state briefly, here, that at this time, task forces were not created. When the Navy Basic War Plan, RAINBOW No. 2 (WPL-46) was issued in May 1941, important directives were contained therein as to the eventual organization of task forces and command relations in the naval coastal frontiers; nevertheless, these directives merely outline the structure of an organization which would not be created until a later order was issued.