United States Naval Construction Battalion flame thrower tanks
During WWII United States Naval Construction Battalions ("Seabees") modified/created all of the main armament flame throwing tanks that were used in the Pacific War: by USMC in the Battle of Saipan, Battle of Tinian, Battle of Iwo Jima, and by the U.S. Army in the Battle of Okinawa. They were a weapon Japanese troops feared and the Marine Corps said was the best weapon they had in the taking of Iwo Jima. After Okinawa the Army stated that the tanks had a psychological presence on the battlefield. U.S. troops preferred to follow them over standard armor for the fear they put in the enemy. Pacific field commanders had tried field modified mechanized flame throwers early on, with the Marine Corps deciding to leave further development to the Army. The Navy had an interest in flame throwing and five Navy Mark I flamethrowers arrived in Hawaii in April 1944. The Navy deemed them "unsuitable" due to their weight and turned the over to the Army's Chemical Warfare Service. In May a top secret composite unit was assembled at Schofield Barracks. It was led by Colonel Unmacht of the US Army Chemical Warfare Service, Central Pacific Area (CENPAC) Col. Unmacht began the project with only the 43rd Chemical Laboratory Company. They modified the first light tank designating it a "Satan". The flame tank group was expanded with men from the 5th Marine tank battalion and 25 from the 117th CB. The newly attached Seabees went over what the Army had created and concluded it was a little over engineered. They recommended reducing the number of moving parts from over a hundred to a half dozen. V Amphibious Corps (VAC) wanted mechanized flamethrowing capabilities for the Marianas operations. VAC had ordered and received two shipments of Canadian Ronson F.U.L. Mk IV flamethrowers (30 flamethrowers in total) to field modify tanks. With a war to wage field modification was much quicker than going through official military procurement channels. The 117th CB was assigned to the upcoming Saipan operation. Col Unmacht worked out an arrangement to not only keep the 117th Seabees he had, but get more. Augmented by the additional Seabees, the group worked sun up to sundown and, with Seabee can-do twenty-four M3s were modified to start the campaign. The very first, made by the 43rd Co, was christened "Hells Afire". The installation configuration of the flamethrower components limited the turret's traverse to 180°. As Satans were produced Colonel Unmacht had the Seabees conduct a comprehensive series of 40-hour classes on flame tank operation with first and second eschelon maintenance. First, for officers and enlisted of the Marine Corps and then later for the Army. The Satans had a range of and were the first tanks to have the main armament swapped for flame throwers. They were divided between the 2nd and 4th Marine Divisions for Siapan and Tinian with Tinian being more favorable to their use. Four Seabees received Navy/Marine Corps commendations for their work from Lt. Gen. Holland M. Smith Commanding