Marine Raiders doing rubber boat training stateside. It was forseen that this was going to be how the Marine Raiders would principally operate in combat.
On January 6, 1942, the Marine Corps redesignated the 1st Battalion, 5th Marines as the 1st Separate Battalion and transferred it from the 1st Marine Division to the direct command of Amphibious Force, Atlantic Fleet, so it could conduct raids not dissimilar to those of British Commandos. However, the commandant directed that this experimental battalion only be referred to as Marines because that term was already good enough to “indicate a man ready for duty at any time and that the injection of a special name such as Commando, would be undesirable and superfluous.” Further, the commandant would go on to state, “The organization, equipment, and training of infantry units of the Marine Divisions should, in practically all respects, be identical to that of the ‘Commandos.’”
On February 4, 1942, at the behest of the Commander in Chief Pacific Fleet, the Commanding General, Amphibious Force Pacific Fleet, ordered the creation of a four-company strength raiding unit that the Marine Corps designated as the 2nd Separate Battalion. To help seed the creation of this new battalion, a company of men from the 1st Separate Battalion was dispatched to help act as cadre.