1863 - Union gunboats pass Confederate batteries at Vicksburg
1924 - Navy commences relief operations in Mississippi Valley floods, lasting until 16 June
1947 - Act of Congress gives Navy Nurse Corps members commissioned rank
1959 - Helicopters from USS Edisto begin rescue operations in Montevideo, Uruguay. By 26 April they had carried 277 flood victims to safety.
(Source: Navy News Service)