An enemy fleet advancing at 18 knots covers about 432 nautical miles in a day; even at 14 knots it covers 336. A destroyer force operating roughly 1,200 nautical miles from base has little time to attack before that fleet comes much closer to the coast. The illustrative fuel budget reserves roughly a third for the outward voyage, a third for combat and a third for the return. Destroyers must then return, reload and sail again while the enemy continues advancing. Their own economical cruising speed makes those transits take days, limiting the number of attacks available before the final engagement.
Chapter · 31:19-34:16
The time and fuel cost of repeated destroyer sorties
An advancing fleet leaves little time for destroyers to attack, return to base, refuel and strike again.