 Complete the following phrase:  In early 1943, stemming from problems found in North Africa, the Army began to consider a more defensive role for tank destroyer units. After trials in January, fifteen battalions were ordered to convert to towed guns on 31 March, and shortly thereafter it was decided that half of all tank destroyer units would convert to a towed organization. The broad outline of the battalion remained  three companies of three platoons of four guns  but the reconnaissance company was downgraded to two platoons in the headquarters company. However, the need for larger gun crews and more security troops meant that the manpower of the unit increased again. These units were equipped with 3-inch M5 guns towed by trucks or M3 Halftracks. However, combat experience in Normandy and Italy  coupled with the fact that purpose-built M18 Hellcat and M36 tank destroyers were becoming available  showed that the towed units were underperforming compared with self-propelled ones. After the 