page_title: Seabees in World War II
section_title: Chemical Warfare Service and Flame Tank Group
hierarchical_section_title: Seabees in World War II / Chemical Warfare Service and Flame Tank Group
caption_attribution_description: English: Cross section through a CB-H1 flame thrower
context_page_description: When World War II broke out the United States Naval Construction Battalions did not exist. The vast oceans between the U.S and the enemy on both sides made the logistics of war a major concern. Rear Admiral Moreell completely understood the issues at hand. What needed to be done was build staging bases and create a military construction force to do build them to take the war to the enemy. The concept of Naval Construction Battalions had been developing at Bureau of Yards and Docks in the 1930s. The onset of war clarified to Radm. Moreell the need to be able to develop advance bases to project American power. The solution was to tap the United States vast pool of skilled labor. Put it in uniform to build anything, anywhere under any conditions and get the Marine Corps to train them. The first volunteers were skilled at enlistment. To obtain these men, military age was modified to take up to 50 years old. It was later found that several past 60 had managed to get in. Men were given advanced rank/pay based upon experience making the Seabees the highest paid group in the U.S. military. The first 60 battalions had an average age of 37.
context_section_description: During WWII Seabees modified/created all of the main armament flame throwing tanks that the USMC put in the field on Saipan, Tinian, Iwo Jima, and the U.S. Army on 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.  A top secret composite unit was assembled at Schofield Barracks Hawaii. Headed 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 40–80 yd (37–73 m) 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 commendations for their work from Lt. Gen. Holland M. Smith Commanding General(USMC) FMF Pacific.
  At least 7 were awarded the Bronze Star.
  Mid-September the Army decided to form a "Flame Thrower Group" and Col Unmacht requested 56 additional Seabees. The group included more CWS and ordnance personnel as well. It was apparent that a larger flamethrower on a bigger tank would be more desirable, but very few tanks were available for conversion. Operation Detachment was next and  Col Unmacht's group located eight M4A3 Sherman medium tanks for it.  The Seabees worked to combine the best elements from three different flame units: the Ronson and the Navy model I and the Navy Mk-1.  MMS1c A.A. Reiche and EM2c Joseph Kissel are credited with designing the CB-H1.  Installation required 150 lbs of welding rod, 1100 electrical connections, and cost between $20,000-25,000 per tank(adj. for inflation $288,000-$360,000 in 2019).  The CB-H1 flamethrower had a range of 400 ft (120 m) and could transverse 270°.   This model was quickly superseded by the CB-H2 that was far better.   EM2c Kissel and another Bee accompanied the tanks to oversee maintenance during the battle of Iwo Jima.  Kissel filled in as an assistant driver/gunner with tank crews on 20 days of the operation.
  In November 1944, prior to the rave USMC reviews of Iwo Jima,  the Fleet Marine Force had requested 54 mechanized flame throwers, nine for each of the Marine Corps Divisions   On Iwo the t
caption: Cross section through a CB-H1 flame thrower
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