Some seven different types of mortars were in use when we came into the war. Our ordnance program contemplated the manufacture of all seven of them, but we actually succeeded in bringing only four types into production. These four were the British Newton-Stokes mortars of the 3-inch, 4-inch, and 6-inch calibers, and the French 240-millimeter mortar, which had also been adopted by the British. As usual in the adoption of foreign devices, we had to redesign these weapons to make them adaptable to American shop methods. We encountered much difficulty throughout the whole job, largely because of insufficient information furnished from abroad, and because in spite of this handicap we had to produce mortars and ammunition that would be interchangeable with French and British munitions stocks.
The first one of these weapons which we took up for production here was the 3-inch Newton-Stokes. The first contract for the manufacture of mortars of this size was placed with the Crane Co., of Chicago, on November 8, 1917, for 1,830 mortars. This concern at once arranged with the Ohio Seamless Tube Co., of Shelby, Ohio, for the drawing of steel tubes for the mortar barrels. This latter concern, however, was already handling large contracts for the Navy and for the aircraft program, and these operations took priority over the mortar contracts. But the Crane Co. took advantage of the interim to build the accessories for the weapons—the tripods, clinometers, base plates, and tool boxes. In the spring of 1918 the company received the first barrel tubes and began producing completed weapons. But when these mortars were sent to the proving ground the test-firing deformed the barrels and broke the metal bases. Finally it was decided that the propelling explosive used was not a suitable one for the purpose. Another was substituted. The new propellant permitted as great a range of fire without damage to the mortar in firing.
The Crane Co. was eventually able to reach a production of 33 of the 3-inch mortars a day, and up to December 5, 1918, it had built 1,803 completed weapons, together with the necessary tools and spare parts. In the early fall of 1918 an additional contract for 677 of these mortars was placed with the Crane Co. and another for 2,000 mortars of this size with the International Harvester Co., of Chicago. Neither of these two latter contracts ever came to the production stage.
A few days after the original contract for 3-inch mortars was let the Trench Warfare Section took up the matter of producing ammunition for these weapons. Two sorts of shell were to be required—live shell filled with high explosive and practice shell made of malleable iron. The original program adopted in November, 1917, called for the production of 5,342,000 live shell for the 3-inch mortars and 1,500,000 practice shell.
3-INCH STOKES TRENCH MORTAR.
4-INCH STOKES TRENCH MORTAR AND AMMUNITION.
