Much has been written about the variety of duties performed by Seabees, but an account of their service has never been told in connection with the pioneering development, actual manufacture and actual use in battle of the Tank Mounted Flame Thrower, which had its humble beginning on a vacant field at Schofield Barracks, Hawaii.
The Commanding General, Pacific Ocean Area, firmly believed that fire and flame would eventually overcome the Japs. He wholeheartedly supported the Chemical Warfare Service in its efforts to produce practical fire and flame weapons. (Ironically, it was considered perfectly proper to ruthlessly burn up the enemy, but absolutely inhumane to use gas.)
Tank mounted flame throwers became the outstanding weapon in routing Japs out of caves and pill boxes. The demand became very great. By the time of the bloody battle of Okinawa, these grim destroyers had reached such popularity that our troops cheered whenever the flame thrower went up the line leading the assault on the enemy.
At Tarawa, November 23, 1943, the Second Marine Division used sixty portable flame throwers which had been issued to them by the Chemical Warfare Service. Their successful employment in a bloody and costly fight killed hundreds of Japs in addition to saving many Marine lives. At a later date, when the writer was asked to explain the issue of Army flame throwers to Marines, he replied, “They were gathering dust in a warehouse so we released them to kill a lot of Japs at Tarawa.”
From this experience, it was apparent to the writer that a tank mounted flame thrower, giving a larger volume of fuel and protection, would effectively reduce our casualties. Mechanized flame throwers had been employed by Russians and Germans, but little information on them was available in this country. Meanwhile, a few Canadian Ronson Flame Throwers were brought in which were designed for mounting on the Bren Gun Carrier, a vehicle poorly adapted for Pacific operations. LVT’s were tried out but too many disadvantages resulted. The officer in charge of all flame thrower tank development in the Pacific Ocean Area decided that the medium tank was the proper vehicle for flame throwers, but unfortunately no medium tanks were available. Twenty-four obsolescent M-3 light tanks were made available by the Ordnance Department. The 43d Chemical Laboratory Company went to work. Fuel tanks were manufactured locally, much redesign was carried out, and the completed weapon appropriately named “Satan.” Demonstrated April 15, 1944, it was unanimously adopted.
At this time several Seabees under the direction of a Chief Warrant Officer (later Lieutenant (jg) (CEC) U. S. Navy), were directed to assist in the modification and inspection necessary for combat readiness. This technical assistance by the Seabees was later to be of greater assistance in furthering the production program of flame thrower tanks. The fuel capacity of these twenty-four tanks was only one hundred and seventy gallons, with a maximum range of sixty to eighty yards. All twenty-four tanks were used by the Second and Fourth Marine Divisions at Saipan and proved very effective. The operators were enthusiastic, which spoke well for the instrument. Whenever the Marines and Infantry were held up, flame thrower tanks were called. At one point two hundred Japs were holed up in a cave with two openings. Machine guns were set to cover one opening; the flame thrower tank, protected by medium tanks, approached the other opening and fired a burst of flame. The Japs ran in terror from the flame thrower fire into the machine gun fire. One hundred and fifty were killed and fifty surrendered. Numerous similar experiences occurred.
m-4 flame thrower tanks
On August 17, 1944, just as the Tenth Army under the command of Lieutenant General Simon Bolivar Buckner, Jr., was being formed, a demonstration was held for high ranking officers of all services at which all types of developments on flame thrower experiments were demonstrated. It was then decided to mount flame throwers in medium tanks of the M-4 series with maximum fuel capacity consonant with operating efficiency. Initial requirements were set at fifty-four for use on Okinawa. Work was begun. A composite group was set up with Navy personnel to assist Chemical Warfare personnel. CINCPAC approved the request for the services of an officer and twenty-five Seabees from the 117th Naval Construction Battalion. This group of experienced technicians did much of the basic work on the mechanized flame throwers. In a few weeks two flame throwers were mounted in experimental models and appropriately named “Hell’s Afire,” and “Confused Buster.” Modifications were made, guns tooled up locally by Seabee, Army, Navy, Marine Corps, and a few Civilian technicians. It was truly a unified composite organization, all enthusiastically and happily working together for the common objective. Almost daily improvements were suggested and adopted. One Seabee technician overnight machined a gun to fit inside the 75 cm. tube. Tenth Army accepted the model. On November 1, 1944, it was designated POA-CWS “75” H-l H-2, with a fuel capacity of 290 gallons.
IWO JIMA CAMPAIGN
Just about this time, the Iwo Jima campaign was entering the initial planning stage. Fleet Marine Force requested urgent priority of eight of these flame thrower tanks to be mounted in M-4A-3 tanks, work to be completed by November 30, 1944. Actual approved order by CINCPAC was received November 15, 1944. On November 30, 1944 these tanks were delivered to the Marines.
SEABEES EXCHANGED FOR TANKS
In order to meet the Tenth Army deadline for fifty-four flame thrower tanks for use at Okinawa, it was agreed in effect that in exchange for these eight tanks for the Marines, we would receive in all fifty-six qualified Seabees. This was done.
Iwo Jima reports again proved conclusively the power and effect of flame thrower tanks. The Fourth Tank Battalion reported, “The Flame Thrower was probably the most valuable single weapon employed at Iwo Jima.” The Twenty-Third Regimental Combat Team reported, “Highly successful. Because of their great utility, more large Flame Thrower Tanks should be provided.” Another combat team reported, “Tanks were probably the most valuable single type of armament in the operation. The special Flame Tanks were probably more useful than the others, especially in the rugged northern areas of the Island.” The Fifth Tank Battalion reported, “The new Flame Tank is an extremely effective piece of equipment. There should be a Company of these tanks per Tank Battalion.”
A Seabee electrician’s mate, who actually operated a flame thrower tank in the front lines for twenty days, wrote in a personal letter from Iwo Jima: “One day we were assigned a pocket to burn out. We did in six hours, with four loads of fuel, what a tank battalion and three Infantry Companies had been trying to do for five days. The Infantry would sooner see one flame thrower tank than a dozen with 75’s. Make sure all spare parts go with each tank. I’m using telephone wire for ignition'—no spare parts as yet, they are on the ocean some place.”
The Commander of the Fifth Marine Division stated, “Events proved that the Flame Thrower Tank was the most important single weapon available to this Division.”
The Okinawa operation clearly demonstrated the successful operation of these fire throwing weapons, and for the first time practical use was made of the hose extension. After the Peleliu campaign, it was seen how difficult it was to get the Japs out of caves in high cliffs such as Bloody Nose Ridge. Overnight our composite Flame Thrower Group produced the answer. “No alibis” was our byword. Our group could “rustle” anything. We discovered that the Navy’s 1 1/2-inch fire hose was better than the Army’s, so the Navy Yard generously gave all they had in fifty foot lengths, and tanks were supplied with four hundred feet of hose.
The fifty-four flame thrower tanks for the Tenth Army were completed January 25, 1945. The 713th Tank Battalion was converted into a Flame Thrower Tank Battalion and provided sixty additional men to assist the Seabees in flame thrower tank construction, thereby gaining experience in maintenance work.
The 713th was in action continuously at Okinawa from April 7, 1945 to June 30, 1945 (85 days). Thousands of Japs were killed and thousands of American lives saved. Flame thrower tanks were used for flaming forward and reverse slopes of hills and escarpments, clearing fox holes and bottle-shaped spider holes dug in the earth, cliff caves, and ruins of structures. The hose extension was used time and again in reaching pockets of Japs which could not be flamed directly. The Commanding General, Seventh Infantry Division, told the writer of one incident where a captain and a sergeant, under covering fire, reached the top of the escarpment with hose extension, and mowed down several hundred Japs with the deadly flame.
The 713th was credited with killing 4788 Japs and capturing 49. Our losses were only 8 killed or missing and 111 wounded, a ratio of 40 to 1.
Following Okinawa, construction was started on seventy-two flame throwing tanks for Fleet Marine Forces.
During the period of one and a half years, our Flame Thrower Group on Oahu produced 354 tank mounted flame throwers, composed of eleven different models, and trained 750 Army, Navy, and Marine Corps personnel as operators and instructors in the technique, operation, and maintenance of tank mounted flame throwers. This is demonstrating what can be done in the field with qualified, resourceful, and enthusiastic personnel. Every man performed outstanding work regardless of hours. Men, of their own accord, worked seventy-five hours per week, although the established hours were sixty. Only one accident occurred where a man was burned by acetylene gas while cutting armor plate, causing sixteen days’ hospitalization. At least seven members of the group were awarded the Bronze Star Medal.
Many thousands of American soldiers, sailors, and Marines are today alive because flame thrower tanks were used to rout out the Japs. This weapon was conceived, produced, and battle tested in the Pacific with resources locally available.
Statistics show that 226,343 gallons of flame thrower fuel were manufactured at the Chemical Warfare Depot at Schofield Barracks. Mixers were built locally to mix the fuel. To install a flame thrower unit in a tank required 1200 man hours of labor; 1100 electrical connections had to be changed and relocated; 150 pounds of welding rod per tank were used, and 150 parts were specially machined by Seabees for each tank. The estimated cost was between twenty and twenty-five thousand dollars per unit.
This oustanding group of Seabees feel that they have been many times repaid in the thought that they were largely responsible for the saving of thousands of American lives because of the weapon they produced.
First enlisting in the Iowa National Guard at sixteen, Colonel Unmacht has had forty-four years of service in the military establishment. He was Chemical Officer in the Pacific Ocean Area during all of World War II, as well as serving as Chemical Officer on the staff of Admiral Nimitz in the Pacific.