Struble, who had directed the Inchon assault from the bridge of the USS _Rochester_, would now fly his flag in the recently arrived USS _Missouri_, the sole American battleship in commission at this early stage of the Korean war.[40] [40] ComSeventhFlt _OpnO 16-50_, 5 Oct 50. [Illustration: WONSAN AND HARBOR MAP-3 ] _Joint Planning for Wonsan Landing_ The Seventh Fleet directive of 5 October dispatched both the Fast Carrier and the Patrol and Reconnaissance Forces of JTF-7 on the usual search and attack missions preliminary to an amphibious assault. Task Force 77, consisting of the carriers _Boxer_, _Leyte_, _Philippine Sea_ and _Valley Forge_, escorted by a light cruiser and 24 destroyers, was under orders to direct 50 per cent of the preparatory air effort against the local defenses of Wonsan. Simultaneously, the Advance Force, with its cruisers, destroyers and mine sweeping units, would close in to shell the target and wrest control of the offshore waters from the enemy.[41] [41] _Ibid._ Topographic and hydrographic studies made available to the Attack and Landing Forces showed Wonsan to be a far more accessible target than Inchon (see Map 3). Nestling in the southwestern corner of Yonghung Bay, 80 miles above the 38th Parallel, the seaport offers one of the best natural harbors in Korea. A vast anchorage lies sheltered in the lee of Kalma Peninsula which, finger-like, juts northward from a bend in the coastline. Tides range from seven to 14 inches, fog is rare, and currents are weak. Docks can accommodate vessels drawing from 12 to 25 feet, and depths in the bay run from 10 fathoms in the outer anchorage to 15 feet just offshore.[42] [42] The description of Wonsan is based upon: GHQ, FECOM, Military Intelligence Section, General Staff, Theater Intelligence Division, Geographic Branch, _Terrain Study No. 6, Northern Korea_, sec v, 13–16; 1stMarDiv _OpnO 15-50_, annex B, sec 2, 1, 3, 10 Oct 50; and 1stMarDiv _SAR_, annex B (hereafter G-2 _SAR_), sec 2, 1. Beaches around Wonsan are of moderate gradient, and the floor at water’s edge consists of hard-packed sand. Though slightly wet landings might be expected, amphibious craft could easily negotiate any of the several desirable approaches. The coastal plain, ranging from 100 yards to two miles in depth, provides an acceptable lodgment area, but the seaward wall of the Taebaek mountain range renders inland egress difficult from the military standpoint. In 1940, the population of Wonsan included 69,115 Koreans and 10,205 Japanese, the latter subsequently being repatriated to their homeland after World War II. Under the Japanese program of industrialization, the city had become Korea’s petroleum refining center. The construction of port facilities, railways, and roads kept pace with the appearance of cracking plants, supporting industries, and huge storage areas.