After the brief flurry of Operation CLAM-UP the front quickly settled down to its old routine of patrols. An average of eight Marine night ambush patrols and five daylight reconnaissance patrols forward of the MLR was maintained. The results left much to be desired. Of the last 110 ambuscades and 75 reconnaissance patrols reported in February, only 1 of the former and 6 of the latter claimed contacts. All but one of the contacts had negligible results.
The Marine fire attack did the enemy more damage. Artillery fired 679 observed missions during the month—211 on troops, 175 on bunkers, 121 on mortars, 96 on artillery, and 75 on such miscellaneous targets as OPs, vehicles, machine guns, and supply points. This total was recorded in spite of an ammunition shortage which would ultimately become the subject of debate in Congress.
Even with supplies of ammunition limited by X Corps orders, Marine artillery drove the enemy from untenable forward-slope positions to underground fortifications on the reverse slope.
Naval gunfire was limited by the extreme range to the Division zone of action.[356] Only large targets forward and to the right of center could be taken under fire. Even so, the Wisconsin and the St. Paul scored some devastating hits in February on enemy reverse slope positions.
[356] The battleship Wisconsin had a main battery of 16-inch guns with a maximum range of about 23 miles. The heavy cruiser St. Paul had a main battery of 8-inch guns with a maximum range of 16 miles.
On one occasion, the Wisconsin erroneously calculated its deflection. Two 16-inch rounds landed between the front line and the 3/7 mortar positions before the fire could be stopped. Fortunately, no one was injured. The Wisconsin Marine officer happened to be visiting the Division CP that day, and on hearing the news he came up to 3/7 and collected a large shell fragment. He stated that he intended to mount the jagged piece of steel in the ship’s CIC room as a reminder to future gunners to make no errors in plot.
Observed direct fire by the 90mm rifles of the 1st Tank Battalion (Major Walter E. Reynolds, Jr.) continued to be effective against NKPA bunkers and gun emplacements. Utilizing the high ground along the MLR, particularly on Hills 812 and 854, tanks sniped at the enemy both by day and night.
This was made possible by the powerful lights of a platoon from the 92d U.S. Army Searchlight Company, attached to the 11th Marines. The mountainous terrain in East Korea was not particularly suited to “artificial moonlight”—the indirect illumination of a large area which results from “bouncing” the rays of searchlights off low-lying clouds. But direct illumination permitted aimed 90mm fire in the darkness and had the further advantage of blinding the enemy to the tanks themselves as well as to troop movements behind them. Not a single light was shot out during the winter in spite of persistent NKPA attempts.
The lessons taught by battlefield illumination in Korea were to be incorporated into two instructive bulletins after the war. “The enemy does not have any better night vision than we do,” asserted USMC Landing Force Bulletin No. 6. “No racial or national group of people has any inherent physical advantage over another as to capability for seeing in darkness....[357] The apparent advantage which the enemy sometimes displays in night operations is due only to a difference in training. In the case of the Oriental soldier, or the Eskimo, for example, training usually begins early in life, where he does not have the convenience of artificial light to the degree we have, and has been forced to make maximum use of his natural night vision in many of his normal activities.
“U.S. Forces have conducted many successful night operations after adequate training. Some units have reported that after intensive night training, personnel have become so proficient that they sometimes prefer night operations to daylight operations.”