Following the destruction of the original concrete bridge, the enemy had blown a temporary wooden structure and an M-2 steel treadway span installed by Army engineers. No prefabricated bridging was available at Hagaru, and time did not permit the construction of a timber trestle bridge. The possibility of Bailey bridge sections was considered but rejected for technical reasons. Finally, after a detailed study of the break from the air on 6 December, Lieutenant Colonel Partridge estimated that four sections of an M-2 steel treadway bridge would be required. Prospects did not appear bright when a bridge section was badly damaged on the 6th after being test-dropped at Yonpo by an Air Force C-119. Nevertheless, it was decided to go ahead the next day with the drop at Koto-ri.[586] [586] Smith, _Notes_, 1057–1059, 1075, 1095–1097; Partridge interv, 25 Jun 51, 48–53; 1stEngBn _SAR_, 13–14. [Illustration: FUNCHILIN PASS AND ADVANCES OF 8–10 December SEIZURE OF HILL 1081 MAP-29 ] There were four U. S. Army treadway bridge (Brockway) trucks at Koto-ri, two of which were operative. After conferring with First Lieutenant George A. Babe of the 1st Engineer Battalion and Colonel Hugh D. McGaw of the 185th Engineer (C) Battalion, USA, Partridge decided to request a drop of eight sections in order to have a 100% margin of safety in case of damage. After analyzing the causes of the unsuccessful test drop, Captain Blasingame of the Air Delivery Platoon had larger parachutes flown to Yonpo from Japan, accompanied by Captain Cecil W. Hospelhorn, USA, and a special crew of Army parachute riggers. Blasingame and a hundred-man work detail from the 1st Amphibian Tractor Battalion worked all night at Yonpo to make ready for the drop next day by eight C-119s of the Air Force. At 0930 on 7 December three of the 2500-pound bridge sections were dropped inside the Koto-ri perimeter and recovered by the Brockway trucks. The remaining five sections were delivered by noon, one of them falling into the hands of the Chinese and one being damaged. Plywood center sections were also dropped so that the bridge could accommodate any type of Marine wheel or tracked vehicle. Thus the tanks could cross on the metal spans only, while the trucks could manage with one wheel on the metal span and the other on the plywood center.[587] [587] Partridge interv 25 Jun 51, 48–53; Capt C. W. Hospelhorn, “Aerial Supply in Korea,” _Combat Forces Journal_, I, no. 10 (May 51), 29–30.