Most transports had already unloaded and departed, demonstrating the speed of Richmond Kelly Turner's amphibious organization. Four cargo vessels still unloading remained exposed near the beachhead. A cruiser force reaching them could cause disproportionate damage, because landing and logistics vessels were not built to absorb heavy shells and torpedoes and their escorts would be drawn into rescue work. Task Force 39 therefore moved to meet the Japanese force before it could reach the bay.
Notable Point · 38:23-43:37
Why Task Force 39 had to intercept
The interception protected the Third Marine Division's lodgment and the last unloading cargo ships from a Japanese surface attack.