In February 1942 the Germans attacked an oil refinery in Aruba, a neighboring island of Curacao just off Venezuela. In The Cay Phillip's father is an expert in gasoline production and oil refineries in Willemstad, Curacao. This causes some worry from Mother because of the attack on the neighboring island.
In addition to the refinery located in Willemstad, ship traffic between, to, and from Curacao and Aruba is virtually stopped due to the German presence. The citizens of Willemstad are afraid of a German attack on the refinery and an invasion of the small island. There is also a shortage of food and supplies to the island due to the blockade of ship traffic. The shortage also causes fear and worry.
In particular, Mother shares the concerns of the townspeople in general and is also afraid for Phillip, who disobeyed her directives about being too close to the water, fort and bridge. She is a nervous woman who wanted to return to Virginia, but cannot due to the blockade.