Only the most basic troop training could be conducted at Kobe to supplement the individual and amphibious instruction the men had received on shipboard. At this time, moreover, an order from the Secretary of the Navy made it necessary to reduce the size of the landing force by withdrawing about 500 Marines who had not yet reached their 18th birthday. They were transferred to the 1st Armored Amphibian Tractor Battalion, which was to be left behind at Kobe when the Division embarked for Inchon. This unit had been organized at Camp Pendleton in accordance with a directive from the Commandant. It was found necessary, however, to transfer most of its combat-ready men to the 1st Tank Battalion in order to bring that outfit up to full strength. The tank battalion was given priority because its vehicles would be used throughout the operation while the armored amphibians might be employed only occasionally. As a consequence, the 1st Armored Amphibian Tractor Battalion left San Diego with new personnel lacking in the skills to make it fully combat ready. Lieutenant Colonel Francis H. Cooper, the commanding officer, recommended at Kobe that the unit be withheld from action until drivers, gunners, and maintenance crews could be properly trained. General Smith and his staff concurred, having learned that a trained Army unit, Company A of the 56th Amphibian Tractor Battalion, could be made available. Orders were given for Cooper’s battalion to remain at Kobe, therefore, with the 17-year-old Marines attached. Several other U. S. Army units were to take part along with the Marines--the 96th Field Artillery Battalion, the 2d Engineer Special Brigade, the 73d Engineer (c) Battalion, the 73d Tank Battalion, the 50th Engineer Port Construction Company, and the 65th Ordnance and Ammunition Company. These units comprised a total of about 2,750 troops. Plans called for the commanding officer of the 2d Engineer Special Brigade to head a logistical task organization which also included several Marine units--the 1st Shore Party Battalion, the 1st Combat Service Group, and the 7th Motor Transport Battalion. The Shore Party troops were to initiate unloading at the objective, whereupon the over-all control would pass to the 2d Engineer Special Brigade, on order, to insure continuity of development of unloading facilities.[107] [107] 1st MarDiv _SAR_, sec. 1, and Annexes Dog and Jig; O. P. Smith, _Notes_, 101, 104, 107, 110–112. Division service units, in accordance with current directives, were to carry the 30-day replenishment of spare parts appropriate to the unit concerned. Although the Combat Service Group had neither spare parts nor supplies, it was to have custody of both after the landing. Thus the units would be freed immediately to move away from the beach in support of the Division as it drove toward Kimpo and Seoul.[108]