Why heavy cruisers had to protect the early carrier raids

American task groups paired carriers with cruisers, destroyers, and oilers because older battleships lacked the speed and fuel economy to accompany them. Heavy cruisers supplied the surface protection that a fast capital ship might otherwise have provided. A typical screen could include three heavy cruisers, one light cruiser, and several destroyers, a force strong enough to deter smaller surface threats but still vulnerable to Japanese battlecruisers. Assigning several scarce heavy cruisers to each carrier also reduced the ships available for convoy, theater, and ABDA commitments. The newly commissioned South Dakota was the only plausible fast battleship during the late raiding sequence, but she was not ready for such a mission and was too valuable to risk casually. The escort problem therefore shaped both the targets the carriers could approach and the other operations the US Navy could support.