Author’s note: The term “retro bomb” is used throughout this article in preference to the alternate “retrorocket,” which to the modern reader might cause confusion. The later term was often used at the time this weapon was in service, as a retrorocket as we know it today had yet to exist.
On 24 February 1944, Patrol Squadron VP-63 scored their first victory against a German U-boat, marking almost two years of development and use of their unique weapon, the retro bomb. Two of their PBY Catalina aircraft drove U-761 to the surface and forced its abandonment off Gibraltar.
Weeks after the United States entered World War II, U-boats appeared off the East Coast and began wreaking havoc on merchant shipping. The U.S. Navy was looking for new solutions, as well as tried ones, to end this disaster.
1. Roscoe Creed, PBY: The Catalina Flying Boat (U.S. Naval Institute Press: Annapolis, 1985).
2. Norman Friedman, U.S. Naval Weapons (Conway Maritime Press: Greenwich, UK, 1983).
3. RADM Curtiss Hutchings, USN (ret), The MAD Cats of Patrol Squadron Sixty-Three (Naval Air Museum Foundation, 1984).
5. Conway W.Snyder, "Caltech’s Other Rocket Project: Personal Recollections," in Engineering and Science Quarterly, Spring 1991.
7. Location of Naval Aircraft, Op-40-A-KB(SC) A6-4/VZ, U.S. Navy official, various dates between 1942 and 1945.
8. U-326, U-392, U-731, and U-761, accessed May 2018
9. Porte-avions et Aéronavale accessed May 2018
10. U-boat Archive accessed July 2018