20th Marine Regiment (United States)

While the 121st NCB remained at Tinian to work on the airfield, the 4th moved on preparing for Iwo Jima.

[6] When the 19th CB was assigned to the Marine Corps 11/05/42 it lost one company and 1/4 of Hq Co.[7] Those men were assigned to the Fleet Marine Force Replacement Group, New River, NC (19th replacement group) which would form the core of the 121st CB when it was formed 05/03/43.

[9] The rest of the island had coral cliffs up to 15 feet in height at the waters edge negating any assault plans.

Commodore Paul J. Halloran (CEC) CB theater commander provided drawings of a conceptual landing ramp for the 18th and 121st CBs to fabricate.

[9] They mounted steel beams salvaged from Saipans abandoned sugar mill on LVT-2s to create a portable assault ramps.

121st NCB landing on Roi-Namur as 3rd Battalion 20th Marines. (Seabee Museum Archives)
Shore Party Blue beach 1, Saipan. The second and third battalions of the 20th Marines were the 4th Marine Divisions shore party on blue and yellow beaches. (National Archives)
LVT-2 assault landing ramp conceived and constructed by the Seabees to facilitate the landing and outflanking of the defenses on Tinian.(Seabee Museum Archives)