The fleet-composition problem carried a direct cost at Hawaii. The Pacific Fleet did not have enough cruisers or destroyers to screen the sortie and also leave an effective naval defence behind. Even the older World War I destroyers were more useful as plane guards or additions to an understrength flotilla than tied to the harbor. Concentrating scarce escorts around the politically important battle line shifted Pearl Harbor's protection toward the Army, shore facilities, and whatever minor craft remained. Strengthening the mobile fleet made the base more vulnerable if Japan attacked after its departure.
Notable Point · 1:20:40-1:21:59
The sortie empties Pearl Harbor's naval screen
Taking every usable escort strengthens the battle line but leaves Pearl Harbor with almost no viable warships for local defence.