The Navy also redeployed United Nations (UN) forces from Chinnampo and Inchon on the west coast.
Militarily usable ports, shown on map 1, then comprised, on the west coast, Chinnampo, Inchon, and Kunsan, dominated by the great tidal range of the shallow Yellow Sea; on the east were Songjin, Hungnam, Wonsan, and Pusan, with deep water just offshore.
On 24 November, having opened Chinnampo for naval logistic support, and supported by Fifth Air Force, Eighth Army units attacked north from the Chongchon River--II Corps on the left, IX Corps in the middle, and the ROK II Corps on the right--with orders to link up with X Corps.
Facing the prospect of simultaneous retrograde movements by Eighth Army on the west coast and by X Corps on the east, Doyle retained overall command of the redeployments but directed Amphibious Group 3, under Rear Admiral Lyman Thackrey, to attend to Eighth Army at Chinnampo and Inchon, leaving Amphibious Group 1, under his direct command, to support X Corps at Songjin, Wonsan, and Hungnam.
The other possible ports had too many strategic disadvantages: Chinnampo, near Pyongyang, was too far north; Posung-Myon presented difficult terrain in its hinterland; and Kunsan was simply too close to Pusan to make it worthwhile.
A British naval task force carried out a bombardment of Chinnampo, and a British frigate landed a raiding party at Kunsan.
This meant that Thackrey conducted operations at Chinnampo
and Inchon largely independently, while Doyle commanded efforts at Songjin, Wonsan, and Hungnam.