Robert B. Kelly, a retired Navy captain whose combat experience as a PT boat commander in the Pacific during World War II became the basis for the best-selling book and movie "They Were Expendable," died of pneumonia. He was 75.

Kelly was executive officer of the famed Motor Torpedo Boat Squadron 3. He won a Navy Cross, the Navy's highest decoration after the Medal of Honor, for sinking a Japanese light cruiser off the island of Luzon in the Philippines on the night of April 8, 1942.He was commander of the lead boat in the four-craft PT boat squadron that evacuated Gen. Douglas MacArthur, his family and staff by night from the island of Corregidor, where the U.S. forces were trapped by the Japanese army, on March 11, 1942. He was awarded a Silver Star for that effort.

Later in the war, Kelly was commander of a PT boat squadron in the Solomon Islands, where he won a second Silver Star for action in combat against the Japanese. One of the men serving under him was Lt. John F. Kennedy, whose boat, PT 109, sank after it was rammed by a Japanese destroyer on the night of Aug. 2, 1943.